October is Breast Cancer Awareness Month, and we want to share stories from customers like Kristy who&#8217;ve taken action after learning she carried a variant in the BRCA1 gene associated with a higher likelihood of developing breast and ovarian cancer. 
Kristy never got to know her dad. He died when she was just two. Her mom, who was busy raising Kristy and her three brothers and three sisters, never shared a lot about him.
And then, in 2016, about 50 years after her father&#8217;s death, Kristy learned something surprising about her dad after using 23andMe.
&#8220;I found out I was half Jewish, specifically Ashkenazi Jewish,&#8221; she said. &#8220;It was fun to get my (23andMe) ancestry results and share them with my six siblings.&#8221;
<h6>Ashkenazi Ancestry</h6>
Raised in a busy midwest Catholic family, Kristy had no idea her dad was 100 percent Jewish. He had left the faith and became a Catholic when he married her mom. The news was interesting; it also reoriented some of what she knew about her family. But at the time, Kristy didn&#8217;t recognize the significance of that family history for her health, and the health of her brothers and sisters and their children.
&#8220;I knew that he was part Jewish, but nothing near 100 percent Jewish,&#8221; she said recently.
It wasn&#8217;t until two years later that she found out just how important knowing her ancestry was. Still, before explaining what happened, it helps to know a little about the uniqueness of Ashkenazi ancestry.
<h6>Ancestry and Health</h6>
The word &#8220;Ashkenazi&#8221; comes from Ashkenaz, a descendant of Noah in the Hebrew bible. People with Ashkenazi ancestry have roots in Jewish communities in Central and Eastern Europe, who had migrated there via Southern Europe. As with many groups, members married and raised families within their faith in these small, close-knit communities. Ashkenazi people were also were more isolated because of violent persecution directed against them from surrounding communities. Over centuries this isolation helped establish a distinct religious, linguistic, and <a href="https://www.hup.harvard.edu/catalog.php?isbn=9780674397316">cultural Jewish identity</a>.
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 <figure class="wp-block-image size-large is-style-default"><img loading="lazy" decoding="async" width="718" height="1024" src="https://blogcms.23andme.com/wp-content/uploads/2021/09/kristy4-718x1024.jpg" alt="" class="wp-image-29152" srcset="https://blogcms.23andme.com/wp-content/uploads/2021/09/kristy4-718x1024.jpg 718w, https://blogcms.23andme.com/wp-content/uploads/2021/09/kristy4-210x300.jpg 210w, https://blogcms.23andme.com/wp-content/uploads/2021/09/kristy4-768x1095.jpg 768w, https://blogcms.23andme.com/wp-content/uploads/2021/09/kristy4-617x880.jpg 617w, https://blogcms.23andme.com/wp-content/uploads/2021/09/kristy4-827x1180.jpg 827w, https://blogcms.23andme.com/wp-content/uploads/2021/09/kristy4-scaled.jpg 1795w" sizes="auto, (max-width: 718px) 100vw, 718px" /></figure>
 
And similar to other culturally or geographically isolated populations, this isolation (and a resulting &#8220;founder bottleneck&#8221;) has created distinct genetic heritage over generations, which can also have implications for health.
So, for example, people with Ashkenazi ancestry are more likely to carry genetic variants that cause single-gene recessive inherited conditions. These include conditions such as <a href="https://www.23andme.com/topics/carrier/gaucher-disease-type-1">Gaucher disease</a>, <a href="https://www.23andme.com/topics/carrier/canavan-disease">Canavan disease</a>, and <a href="https://www.23andme.com/topics/carrier/tay-sachs-disease">Tay-Sachs disease</a>. People of Ashkenazi ancestry also have a higher prevalence of genetic variants in the BRCA1 and BRCA2 genes associated with increased risk for breast, ovarian, prostate, and certain other cancers.
Kristy knew none of this.
<h6>A New Genetic Health Risk Report</h6>
Then in 2018, 23andMe released its BRCA1/BRCA2 (Selected Variants) Genetic Health Risk* Report, the first direct to consumer genetic test for inherited cancer authorized by the FDA. The report looks at three of the BRCA variants most common in people of Ashkenazi ancestry. Women with one of these variants have a 45-85 percent risk of developing breast cancer by age 70, compared to about 13 percent in the general population. In addition, having one of these variants increases the risk for ovarian cancer. After opting to receive the information and going through a tutorial about the report, Kristy opened up her results.
She had one of the variants in the BRCA1 gene.
&#8220;And so began an almost two-year journey of discovering what this all meant,&#8221; she said.
<h6>Kristy&#8217;s Health Journey</h6>
For Kristy, it meant consulting five different doctors and talking to a genetic counselor to best understand her risk. Initially, her doctor did a confirmatory test. She did indeed carry the variant. Then, working with her doctors, they looked at her family medical history. An aunt had died of ovarian cancer, and a grandmother had survived ovarian cancer. They used all this information to give their best estimate for her risks.
&#8220;I think I had a 50 percent risk for ovarian cancer and up to an 80 percent risk for breast cancer,&#8221; Kristy said. 
Her aunt had died of ovarian cancer at 52, and Kristy, nearing that age herself, didn&#8217;t want to wait. She decided to have preventative surgeries, a double mastectomy, and an oophorectomy (removal of her ovaries). Later Kristy had reconstructive surgery. It was an emotional and at times frightening period. But what she hadn&#8217;t expected was how hard it was to talk to her family about it. 
Not only did the knowledge about her own risk also have implications for her sisters, but also her brothers. Like Kristy, they all could have inherited the same risk variant. And it wasn&#8217;t just about her siblings but their children as well.
&#8220;My family, in particular my sisters, were having a tough time understanding why I was going through this, and then why they may have to go through it too,&#8221; she said.
<h6>Talking to Family</h6>
At first, they thought she might be overreacting. So because of that response, Kristy went back to her genetic counselor to once again review all the findings. She wanted to make sure she understood the risk, and reconfirm her decision.
&#8220;I went through all the numbers and the family health history and everything to make sure I was doing the right thing,&#8221; she said.
It took a while for them to grasp the importance of it all. But eventually, all of her sisters and two of her three brothers tested. All three of her sisters had the variant, as well as one of her brothers. Eventually, they were able to share information to help each other work through what to expect. For her siblings with children, it&#8217;s information they could share with them as well.
<h6>A Gift</h6>
But if it weren’t for Kristy&#8217;s 23andMe reports, they may have never known.
Indeed, many people who carry a BRCA genetic variant associated with an increased risk for breast, ovarian, prostate, and certain other cancers only find out that they have one of those variants after they&#8217;ve been diagnosed with cancer. They often don&#8217;t have a family history of cancer or don&#8217;t know their family medical history or ancestry. These are all used to evaluate whether a patient should get BRCA testing. A study by 23andMe researchers published last year in the journal <a href="https://www.nature.com/articles/s41598-020-63466-x">Scientific Reports</a> found that many of those individuals who carry one of the BRCA risk variants that 23andMe tests for are likely to be missed under current clinical testing criteria. 
For Kristy, the knowledge gave her and her family potentially lifesaving information.
&#8220;I was given the gift of knowing,&#8221; she said. &#8220;Some people never get that chance.&#8221;
Learn more about the BRCA gene and its role in some cancers <a href="https://www.23andme.com/brca/">here</a>.
<hr />
*The 23andMe PGS test uses qualitative genotyping to detect select clinically relevant variants in the genomic DNA of adults from saliva for the purpose of reporting and interpreting genetic health risks and reporting carrier status. It is not intended to diagnose any disease. Your ethnicity may affect the relevance of each report and how your genetic health risk results are interpreted. Each genetic health risk report describes if a person has variants associated with a higher risk of developing a disease, but does not describe a person’s overall risk of developing the disease. The test is not intended to tell you anything about your current state of health, or to be used to make medical decisions, including whether or not you should take a medication, how much of a medication you should take, or determine any treatment. Our carrier status reports can be used to determine carrier status, but cannot determine if you have two copies of any genetic variant. These carrier reports are not intended to tell you anything about your risk for developing a disease in the future, the health of your fetus, or your newborn child’s risk of developing a particular disease later in life. For certain conditions, we provide a single report that includes information on both carrier status and genetic health risk. Warnings &amp; Limitations: The 23andMe PGS Genetic Health Risk Report for BRCA1/BRCA2 (Selected Variants) is indicated for reporting of the 185delAG and 5382insC variants in the BRCA1 gene and the 6174delT variant in the BRCA2 gene. The report describes if a woman is at increased risk of developing breast and ovarian cancer, and if a man is at increased risk of developing breast cancer or may be at increased risk of developing prostate cancer. The three variants included in this report are most common in people of Ashkenazi Jewish descent and do not represent the majority of BRCA1/BRCA2 variants in the general population. This report does not include variants in other genes linked to hereditary cancers and the absence of variants included in this report does not rule out the presence of other genetic variants that may impact cancer risk. The PGS test is not a substitute for visits to a healthcare professional for recommended screenings or appropriate follow-up. Results should be confirmed in a clinical setting before taking any medical action. For important information and limitations regarding other genetic health risk reports and carrier status reports, [visit<a href="https://www.23andme.com/test-info/"> https://www.23andme.com/test-info/</a>].

23andMe Blog

23andMe Blog Team

The Gift of Knowing

Xin Fang’s interest in science started at the dinner table, listening to her parents talking about what they did each day. 
Both her mom and dad are plant scientists. Her mom focuses on genetics, and her father on the environment. They worked long hours, but they would come home enthused. And, sitting with her parents at the table for the family meal, Xin listened as her mom and dad engaged in conversations about the latest discoveries made or problems solved. It fascinated her.<img loading="lazy" decoding="async" src="https://blog-api.23andme.com/wp-content/uploads/2021/09/XinFang1-200x300.jpg" alt="" class="alignright wp-image-29144 size-medium" width="200" height="300" srcset="https://blogcms.23andme.com/wp-content/uploads/2021/09/XinFang1-200x300.jpg 200w, https://blogcms.23andme.com/wp-content/uploads/2021/09/XinFang1-683x1024.jpg 683w, https://blogcms.23andme.com/wp-content/uploads/2021/09/XinFang1-587x880.jpg 587w, https://blogcms.23andme.com/wp-content/uploads/2021/09/XinFang1-787x1180.jpg 787w, https://blogcms.23andme.com/wp-content/uploads/2021/09/XinFang1-768x1152.jpg 768w, https://blogcms.23andme.com/wp-content/uploads/2021/09/XinFang1-scaled.jpg 1706w" sizes="auto, (max-width: 200px) 100vw, 200px" />
<h3>The Wonders of Human Biology</h3>
Now a computational biologist in 23andMe’s Therapeutics division, Xin said her parents’ passion for science fueled her own ambition. By high school she knew she wanted to be a scientist, she just wasn’t sure about her path. Moving from China to the United States to attend Johns Hopkins University, Xin studied chemical and biomolecular engineering. It was there that her interest in bioinformatics took root. She was fascinated by the “mystery of the human body and how it works,” she said. Xin was sucked into the fact that data and bioinformatics offered a door to understanding parts of the mystery of human biology.
“I love the fact that we can develop new techniques to understand the mechanisms behind human biology,” Xin said.
Now a little over a year into her work at 23andMe, Xin is deep into collaborating with fellow computational biologists and bench scientists to help find potential drug targets to pursue. Computational biology, data science, and machine learning play a critical role in 23andMe’s drug discovery process. Our scientists have the great fortune of gleaning insights from what is one of the largest genetic and phenotypic datasets in the world.
For Xin, the attraction of coming to work at 23andMe wasn’t just that she’s interested in genetics or that she sees the promise of 23andMe’s data helping to accelerate the development of new treatments, it’s also because drug discovery at 23andMe is driven by data, which allows computational biologists like her to propose new research directions and make major contributions. The size and scale of our dataset enables rapid discoveries.
As part of an occasional series about scientists working at 23andMe, we sat down with Xin to talk about computational biology, 23andMe, and what it’s like being an early career scientist here.
<h6>Did you always want to be a scientist?</h6>
Pretty early on I did. By high school, I knew I wanted to do something in biochemistry but I wasn’t sure what.
<h6>Was your interest in science inspired by a person or an experience?</h6>
Definitely it came from my parents. They were both scientists and very passionate about it, and it had a great impact on me. They worked a lot but they were happy about what they were doing. We spent a lot of hours talking about their work over dinner.
<h6>You studied chemical and biomolecular engineering at Johns Hopkins, what prompted you to do your doctoral work in bioengineering?</h6>
I took a gap year working at Genentech after my undergraduate studies. That and my experience during undergrad helped me realize that I was more interested in bioinformatics and computational modeling.
Consider the human body. It’s this perfect mystery that it works in a way that it does, and we don’t totally understand it. But when you bring in high-throughput data, especially from large genomics datasets or next-generation sequencing, you start to see more clearly different biological mechanisms at play. That’s the most fascinating part. And I love that we can use these new techniques and assays to try and understand it. It’s just awesome.
<h6>Why did you focus on studying the gut microbiomes and IBD during your doctoral work at UCSD?</h6>
The gut microbiome is a significant part of our body but it hasn’t been well understood before. It interacts with the rest of the human body in a lot of different ways including things like exchanging metabolites and breaking down medicines. And in recent years it has been discovered that the gut microbiome is associated with several diseases and inflammatory bowel disease (IBD) is one of them.  Basically, what you observe is an imbalance in the microbiome where there is a reduction in the beneficial microbes but an increase in pathogens. My thesis looked at characterizing if there are any specific pathogens associated with developing inflammatory bowel disease. The second part of what I did was to look at how the microbiome could affect the treatment for IBD.
<h6>What attracted you to working for 23andMe’s Therapeutics team?</h6>
I was a 23andMe customer even when I was a broke Ph.D. student. And I’m in bioinformatics and a huge fan of genetics. I’ve always been a strong believer that personal genetics is going to make its way into modern medicine, and become a part of standard practice.
So, when I was looking for a job, 23andMe was a company I was really interested in. But to be honest I didn’t know much back then about 23andMe’s Therapeutics program. I didn’t know about 23andMe’s unique approach to target discovery or the drug pipeline. It wasn’t really until the interview and until I had the opportunity to talk to the Computational Biology team that I fully understood what the Therapeutics program was about and it was really exciting.
A major advantage we have is the size of our database. And this is extremely important in terms of discovery because we have better power to detect genetic signals useful for identifying drug targets that other databases can’t. And of course, our data comes from customers who consented to participate in research and who we can contact in the future if we need to. So, that’s another advantage. 
<h6>Describe a little bit about some of what you do in your day-to-day work.</h6>
I can divide my current role into two different aspects that support our therapeutics discovery and development process. The first is to help with data analysis in support of identifying biomarkers that could be useful for clinical trials. I am also working on developing automatic reports for later stage programs. 
And the second part of my job is more upstream, on integrating different datasets to improve the variant (GWAS hit) to target gene mapping process. We want to identify genes that are actually affecting the disease and understand the mechanism of action.
<h6>What’s different about working here?</h6>
For me, I guess what influenced my decision to come here is that 23andMe is doing genetics-based, data-driven discovery. So as part of the Computational Biology team, you can make major contributions to drug discovery whereas in a more traditional biotech/pharma setting Computational Biology would play much more of a supporting role.
As a scientist, I am very interested in doing research and exploratory projects that are intellectually challenging and at 23andMe we have the opportunity to do these things.
<h6>How have you managed your work-life balance over the last year during the pandemic?</h6>
I’m working primarily from home but I go to the office two or three times a week. At first, it was hard because I started at 23andMe during the shelter in place while we were all working from home. But the team has been really good about meeting each week and making sure questions are answered so I don’t feel like I’m by myself all the time. And there is a good work-life balance.
<h6>What interests you outside of work?</h6>
I used to play a lot of badminton. I actually trained for it as a kid, but stopped playing in grad school and shifted over to table tennis. In the office we have a table tennis tournament going on after the work hours, so that’s fun. And during the pandemic, I got a puppy so that’s occupying my time right now too.

Helping to Drive Discovery in 23andMe’s Therapeutics Division

The first thing you notice about Aaron Harris is his ever-present smile.
It punctuates his conversation even when he describes the parts of his life that were dark and joyless.
Born premature, at just 26 weeks, Aaron was a &#8220;micro-preemie&#8221; who struggled in his first year just to survive.
He came into this world addicted to the same opiates that his mother and father had been using. He weighed just one pound, 4 ounces, and spent his first months on oxygen. The doctors and nurses who cared for him didn&#8217;t think he would make it. If he survived, they feared he&#8217;d end up blind or deaf. That didn’t happen but it was a struggle. By the time he was one, his parents — who had two infants, twins born less than a year before Aaron — had abandoned him to foster care.
&#8220;I went through a lot,&#8221; he said with a smile and a nod of his head.

 <figure class="wp-block-image size-large is-style-default"><img loading="lazy" decoding="async" width="512" height="512" src="https://blogcms.23andme.com/wp-content/uploads/2021/09/aaron-harris-1.png" alt="" class="wp-image-29124" srcset="https://blogcms.23andme.com/wp-content/uploads/2021/09/aaron-harris-1.png 512w, https://blogcms.23andme.com/wp-content/uploads/2021/09/aaron-harris-1-150x150.png 150w, https://blogcms.23andme.com/wp-content/uploads/2021/09/aaron-harris-1-300x300.png 300w, https://blogcms.23andme.com/wp-content/uploads/2021/09/aaron-harris-1-271x271.png 271w, https://blogcms.23andme.com/wp-content/uploads/2021/09/aaron-harris-1-372x372.png 372w" sizes="auto, (max-width: 512px) 100vw, 512px" /></figure>
 
<h2>A Revelation</h2>
He&#8217;s now trying to unravel it all. So that he can understand where he came from, who he&#8217;s related to, and maybe a bit of what makes him who he is now. Several years ago, an aunt gave him 23andMe as a gift. It was a revelation for someone who was adopted and didn&#8217;t know much about his origins.
&#8220;I didn&#8217;t even know any medical history,&#8221; said Aaron, who is making a documentary about his experience called And Then There Were Seven.
He always assumed he was Latino because of his complexion but learned through 23andMe that he was Native American. Suddenly the Native American summer camps he happened to go to and the draw of the culture made more sense.
&#8220;It&#8217;s really cool to get a glimpse of my genetics,&#8221; he said. &#8220;So, I&#8217;m like 60 percent white guy, which is super funny because I&#8217;m brown. But I find out I&#8217;m 40 percent Native American.&#8221;
<h2>Authentic Self</h2>
Knowing that bit about himself helped a lot.
&#8220;It helped me pursue my authentic self,&#8221; he said.
Yet Aaron also wanted to know about any siblings out there. In part, he was worried about the children his birth parents kept, the twins. He&#8217;d learned about them from his adoptive mom and never stopped thinking about them.
Despite everything he went through physically, the only lingering physical effect was scarring in his airways from the oxygen tubes used to help him breathe in the ICU. He has pulmonary dysplasia and is prone to bronchitis and pneumonia. But instead of hardening him, the emotional scars of those early experiences and being abandoned by his birth parents created in him a deep well of empathy for others. He knew he was lucky. He wanted to know what happened to his siblings.
<h6>You&#8217;re Meant to be Aaron&#8217;s Mom</h6>
During his first three years, he was largely cared for by nurses or foster parents, but a woman, a play therapist, would visit during that time. Her name was Eva and she bonded with Aaron. She’d come when it wasn&#8217;t her shift, ensuring he had a stable caregiver. She was concerned he&#8217;d have trouble bonding if someone didn&#8217;t interact with him. She would give him bottles regularly, take him for walks in the stroller when he was stronger. At one point, Aaron wound up back in the hospital.
His foster mom looked at the play therapist and said, &#8220;I think you&#8217;re meant to be Aaron&#8217;s mom.&#8221;
Eva was still young and only recently married. She and her new husband, Shane, a rookie firefighter, adopted Aaron. A day later, she discovered she was pregnant with Aaron&#8217;s adoptive sister, Tatum.
Aaron grew up in Ventura. During his teen years and early 20s, Aaron began to come to terms with his gender identity, eventually transitioning to male. That experience gave him an innate connection with outsiders, the forgotten, and people looked over or cast away by others. He also never forgot that he had siblings out there, the twins. Both Aaron and his mom never stopped thinking about those two kids. They worried about them.
<h2>Searching</h2>
Aaron had tried a bit of sleuthing to find them. A few years ago he&#8217;d posted what information he had about his birth parents on a search site for adoptees — names from his adoption and social service records. He&#8217;d found some newspaper clippings related to criminal cases against his parents that included a description of his birth mom&#8217;s tattoo. That helped lead him to his paternal uncle. But once the uncle learned that Aaron was transgender, he ended contact with him.
Aaron kept searching.
Fast-forward to May 2021. He saw he had a new 23andMe DNA Relative match with a first cousin. They quickly connected. Within half an hour, he learned from his cousin that he didn&#8217;t have just two siblings, but six, and that they&#8217;d all been adopted by a couple in Maryland—Heidi and Doug—who had two children of their own. The couple had promised their birth mom that she would keep them together.
In all, his birth parents, who struggled with addiction and were in and out of jail, had seven children born in five years. There were two sets of twins, and six of the seven children were like Aaron, born addicted to opiates. Five were born prematurely.
Aaron&#8217;s cousin helped him connect with each of the siblings in a group chat. They&#8217;d known about Aaron, having learned about him through their uncle, and they knew he was transgender, but that wasn’t an issue for them. They just wanted to find him. <img loading="lazy" decoding="async" class="alignright wp-image-29123 size-full" src="https://blog-api.23andme.com/wp-content/uploads/2021/09/aaron-surrounded-by-siblings.png" alt="" width="274" height="512" srcset="https://blogcms.23andme.com/wp-content/uploads/2021/09/aaron-surrounded-by-siblings.png 274w, https://blogcms.23andme.com/wp-content/uploads/2021/09/aaron-surrounded-by-siblings-161x300.png 161w" sizes="auto, (max-width: 274px) 100vw, 274px" />
Once she learned he&#8217;d found his siblings, Aaron&#8217;s mom insisted he see them as soon as possible. So he, his mom, Eva, and his sister Tatum flew to Maryland a few weeks later to meet his newfound siblings.
&#8220;Tatum said it was like being with a bunch of alternate versions of me,&#8221; Aaron said. &#8220;We&#8217;re just so much alike, and I can see myself in all of them.&#8221;
<h2>Permission</h2>
During his time in Maryland, Aaron also had the chance to meet his birth mom.
Despite everything, he said that at least she knew she couldn&#8217;t care for her children and helped ensure that they stayed together and were adopted by the same family. Heidi and Doug, the couple in Maryland who, with their two biological children, helped keep them a family.
But Aaron also said that he harbors some anger toward her and his birth father as well. He had so many questions he knew she wouldn&#8217;t be able to answer. And although she was pleasant to him, she also avoided being alone.
&#8220;It&#8217;s hard because I try to be patient, loving, and kind, but I had these feelings,&#8221; Aaron said. &#8220;It still hurts.&#8221;
But he also felt empathy for her and himself, permitting himself to feel the way he felt. But more striking was what he felt toward his siblings. This powerful connection wasn&#8217;t just biological. It was that they, too, had experienced the same pain. He thought about how all of them had survived despite an early life marred by drug abuse, poverty, and neglect. They&#8217;d each been given a second chance by families who adopted them loved them, and raised them to be who they are.
And it&#8217;s that idea that drives him now.
&#8220;I want to share our story of struggle, adoption, perseverance, hope, family, and love with the world.&#8221;

Aaron Harris standing with his two brothers and four sisters.

An Adoptee’s Search

A welcomed pregnancy comes with all sorts of emotions—most often joy, excitement, and maybe a little anxiety.
You can take steps before getting pregnant that can go a long way toward tamping down some of that worry and supporting your and your baby&#8217;s health through your pregnancy and beyond. Of course, learning more about your health is a great start. It&#8217;s also important to know that simple day-to-day actions like exercising and watching your diet can help set you on the right path.
<h6><img loading="lazy" decoding="async" class="aligncenter wp-image-29130 size-large" src="https://blog-api.23andme.com/wp-content/uploads/2021/09/PRS-Gestational-Diabetes-Blog-1200x628-1-1-1024x536.png" alt="" width="1024" height="536" srcset="https://blogcms.23andme.com/wp-content/uploads/2021/09/PRS-Gestational-Diabetes-Blog-1200x628-1-1-1024x536.png 1024w, https://blogcms.23andme.com/wp-content/uploads/2021/09/PRS-Gestational-Diabetes-Blog-1200x628-1-1-300x157.png 300w, https://blogcms.23andme.com/wp-content/uploads/2021/09/PRS-Gestational-Diabetes-Blog-1200x628-1-1-768x402.png 768w, https://blogcms.23andme.com/wp-content/uploads/2021/09/PRS-Gestational-Diabetes-Blog-1200x628-1-1-880x461.png 880w, https://blogcms.23andme.com/wp-content/uploads/2021/09/PRS-Gestational-Diabetes-Blog-1200x628-1-1-1180x618.png 1180w, https://blogcms.23andme.com/wp-content/uploads/2021/09/PRS-Gestational-Diabetes-Blog-1200x628-1-1.png 1200w" sizes="auto, (max-width: 1024px) 100vw, 1024px" />Gestational Diabetes</h6>
23andMe recently released a new 23andMe+ Premium report on gestational diabetes report. Powered by 23andMe research, this new report uses machine learning techniques to estimate a person&#8217;s likelihood of developing gestational diabetes. To make that estimate, we use a statistical model that looks at a person&#8217;s ethnicity and more than 6,000 genetic variants associated with developing gestational diabetes mellitus, commonly known as gestational diabetes.
Fortunately, it&#8217;s a condition that is largely preventable. While genetics plays a role, healthy lifestyle habits before pregnancy, like maintaining a healthy weight, eating a balanced diet, exercising, and not smoking, can lower your risk.
So, what is gestational diabetes?
During pregnancy, <a href="https://www.cdc.gov/diabetes/basics/gestational.html">your body changes</a>. It adapts to make more hormones, and you put on weight. In turn, your body’s cells aren’t able to use insulin, a hormone that’s instrumental in regulating your blood sugar levels, as effectively. This is known as “insulin resistance,” which is common during pregnancy. Typically, the body responds by producing more insulin. However, gestational diabetes occurs when your body can&#8217;t produce enough insulin to meet the increased need, resulting in blood sugar levels that are too high. <img loading="lazy" decoding="async" class="wp-image-29128 size-medium alignright" src="https://blog-api.23andme.com/wp-content/uploads/2021/09/gd-story-1.c7f99f33b94c.svg" alt="" width="300" height="300" srcset="https://blogcms.23andme.com/wp-content/uploads//2021/09/gd-story-1.c7f99f33b94c.svg 150w, https://blogcms.23andme.com/wp-content/uploads//2021/09/gd-story-1.c7f99f33b94c.svg 300w, https://blogcms.23andme.com/wp-content/uploads//2021/09/gd-story-1.c7f99f33b94c.svg 1024w" sizes="auto, (max-width: 300px) 100vw, 300px" />
<h6>The Numbers</h6>
Unfortunately, gestational diabetes has become much more common as the rates of obesity have risen. The Centers for Disease Control and Prevention estimates that between <a href="https://www.cdc.gov/reproductivehealth/maternalinfanthealth/diabetes-during-pregnancy.htm">6 percent and 9 percent</a> of those expecting will develop the condition, which is often preventable. The risk for gestational diabetes is particularly high among African Americans, Asian Americans, and people of Hispanic/Latino, Indigenous American, and Pacific Islander descent.
Gestational diabetes typically occurs without any symptoms but can have longer-term impacts on your and your baby&#8217;s health. For example, those with gestational diabetes are more likely to develop high blood pressure during pregnancy or have a larger baby that requires a cesarean section for delivery. Gestational diabetes also increases the parent and child’s chances of developing type 2 diabetes later in life.
All this adds to the importance of knowing your potential of developing gestational diabetes. Beyond genetics, there are other factors that can increase your chances. For example, having had gestational diabetes in a previous pregnancy increases the likelihood of developing it again in a subsequent pregnancy. So too does having prediabetes, polycystic ovary syndrome, or a family history of diabetes, increase one’s chances. Being overweight also adds to the likelihood. And as people get older, this condition tends to be more common. If you may become pregnant, sharing whether you have any of these factors with your health care provider is important. They may suggest testing earlier during pregnancy to know for sure if you have gestational diabetes.
<h6>Taking Action</h6>
Understanding more about your genetic and non-genetic factors that may influence your likelihood of developing gestational diabetes might be the knowledge you need to spur action. Then, you can lower your risk.
Remember to talk with your healthcare provider before making any significant lifestyle changes. That said, before pregnancy, maintaining a healthy weight, eating right, and getting plenty of exercise can go a long way toward better health in the long run.
23andMe&#8217;s new Gestational Diabetes report (Powered by 23andMe Research) is available to all 23andMe+ Premium members who report their birth sex as female. To learn more about your report, go <a href="https://you.23andme.com/reports/prs.gestational_diabetes/">here</a>.
Not yet a customer? Find out more about 23andMe+ Premium <a href="https://www.23andme.com/membership">here</a>.
<hr />
*Note: The 23andMe Gestational Diabetes report is based on 23andMe research and incorporates more than 6,000 genetic variants to provide information on the likelihood of developing gestational diabetes mellitus. The report does not account for lifestyle or family history and has not been reviewed by the US Food and Drug Administration. Visit www.23andme.com/topics/health-predispositions/ for additional important information on 23andMe&#8217;s Health Predisposition reports.

Taking Control for a Healthier Pregnancy 

Among his many jobs as 23andMe senior scientist in statistical genetics, Suyash Shringarpure, Ph.D. leads some of our rare disease discovery and prediction work.
But since first coming here in 2016, he’s been involved in a wide variety of projects all leaning on his extensive background in machine learning. Suyash came here after doing post-doctoral work in Carlos Bustamante’s Lab at Stanford University where he worked on genetic data privacy, ancestral inference, and next-generation genetic sequencing. He received his Ph.D. in Machine Learning from Carnegie Mellon University, and he received his undergraduate degree in Computer Science and Engineering from the Indian Institute of Technology in Bombay.
<div id="attachment_28941" style="width: 228px" class="wp-caption alignright"><img loading="lazy" decoding="async" aria-describedby="caption-attachment-28941" src="https://blog-api.23andme.com/wp-content/uploads/2021/06/©PITER2017Suyash-Shringarpure2649-218x300.jpg" alt="" class="wp-image-28941 size-medium" width="218" height="300" srcset="https://blogcms.23andme.com/wp-content/uploads/2021/06/©PITER2017Suyash-Shringarpure2649-218x300.jpg 218w, https://blogcms.23andme.com/wp-content/uploads/2021/06/©PITER2017Suyash-Shringarpure2649-768x1056.jpg 768w, https://blogcms.23andme.com/wp-content/uploads/2021/06/©PITER2017Suyash-Shringarpure2649-745x1024.jpg 745w, https://blogcms.23andme.com/wp-content/uploads/2021/06/©PITER2017Suyash-Shringarpure2649-640x880.jpg 640w, https://blogcms.23andme.com/wp-content/uploads/2021/06/©PITER2017Suyash-Shringarpure2649-858x1180.jpg 858w, https://blogcms.23andme.com/wp-content/uploads/2021/06/©PITER2017Suyash-Shringarpure2649-scaled.jpg 1862w" sizes="auto, (max-width: 218px) 100vw, 218px" />Suyash Shringapure, Ph.D., a 23andMe senior scientist, and statistical geneticist.</div>
There’s a lot we could talk about because his work touches so many parts of the company — from research and development for our health product team, to work in support of Therapeutics, to some of the backend technical efforts related to things like the phasing of genetic data. But we sat down, virtually, to talk to Suyash specifically about his work on rare diseases at 23andMe. This is one in an occasional series we’ve been doing over the last few months looking at rare diseases. Suyash recently spoke about his research at the National Press Foundation as part of <a href="https://hopin.com/events/rare-and-mystery-diseases">a session on rare diseases</a>. (We will post a recording of the session when it becomes available.) 
In the spring we published new research led by Suyash looking specifically at the unique way 23andMe can<a href="https://blog.23andme.com/23andme-research/new-way-to-study-rare-disease/"> study rare diseases.</a> It offered some unexpected insights into these hard-to-study conditions.
“This approach will enable us to discover new genetic associations across multiple populations much faster than could be done otherwise,” he said at the time.
Read on to find out more about what he had to say:
<h6>Even before you came to 23andMe, you were known for using machine learning and statistical methods for work on a broad range of different scientific problems. Why is machine learning such a powerful tool in genetics and biology and for the study of disease?</h6>
Genetics has become a data-rich field in the last couple of decades. There are now many large human genetic (and gene expression etc.) datasets available for researchers. Because the genetic risk for most common diseases is an aggregate of many different genetic variants — sometimes hundreds even thousands of variants — machine learning and statistical methods offer a powerful tool in calculating disease risk. In genetics and biology, these algorithms can infer the small contributions of many genetic variants and combine them appropriately to describe disease risk.
<h6>Why are you and other scientists at 23andMe so interested in rare diseases, and why are we studying<a href="https://www.23andme.com/systemic-sclerosis-study/"> systemic sclerosis</a>, and<a href="https://www.23andme.com/idiopathic-pulmonary-fibrosis/"> idiopathic pulmonary fibrosis (IPF)</a> in particular?</h6>
Though each rare disease only affects a small number of people, there are nearly 7000 known rare diseases, and the total number of people affected by rare diseases is quite large. It’s estimated that about 20-25 million Americans and 300 million people worldwide are living with a rare disease. In addition, about 70 percent of all rare diseases are genetic, while only 5 percent of all rare diseases have approved treatments. So there is a large unmet need for therapeutics for rare diseases, which is why we at 23andMe are so interested. Beyond the need, our large database is also well-suited for studying rare diseases. It’s often difficult to study rare diseases because it is a challenge to find enough individuals to participate in research. But 23andMe now has enough people who have consented to participate in research that we can more quickly gather enough individuals with a specific rare disease to find statistically robust genetic associations.
Idiopathic pulmonary fibrosis (IPF) is a life-threatening, progressive lung disease with a median survival of three to five years after diagnosis. The genetics of IPF is not well-understood, and at present, there are only two FDA-approved therapies, and unfortunately, neither is always well-tolerated by patients. We believe we can use our research model to find insights into the disease, and that’s why we started our <a href="https://www.23andme.com/idiopathic-pulmonary-fibrosis/">IPF Study</a>.
Similar to IPF, Systemic sclerosis is a rare disease for which there is an unmet need for treatments. Systemic sclerosis is an autoimmune disease that affects the skin and internal organs, and we don’t fully understand the genetics of the disease.  Much like with our IPF Study, we launched our <a href="https://www.23andme.com/systemic-sclerosis-study/">Systemic Sclerosis Study</a> to better understand the genetics of the condition and to improve our ability to discover new genetic associations for these diseases.   
<h6>You completed an <a href="https://blog.23andme.com/23andme-research/new-way-to-study-rare-disease/">interesting study</a> using 23andMe’s unique research model to study rare diseases. Were those findings a surprise when you made them?</h6>
Some of them were definitely a surprise. We have lots of experience in studying common diseases, where we need to have tens of thousands of affected individuals in our study to find statistically significant genetic associations. It was a surprise for us when we were able to find genetic associations in studies of rare diseases with only tens of affected individuals. Another surprise was finding that common genetic variants show association with rare disease risk. Previously, it has been found that rare genetic variants cause rare diseases, so this was unexpected. Unsurprisingly, we found that similar regions of the genome contribute to risk in different populations and that aggregating data across all populations enables us to make the most discoveries. 
<h6>What makes 23andMe’s research model unique for studying rare diseases?</h6>
The main bottleneck in studying rare diseases is finding enough people with the condition to participate in the research. 23andMe’s large research-consented cohort means that even for a disease that affects one-in-100,000 people, we can find nearly 100 affected individuals for our analysis. The self-reported data-collection model we have also allowed us to study thousands of diseases at once, rather than studying one disease at a time. So for example, in the study we just published on the preprint server <a href="https://www.medrxiv.org/content/10.1101/2021.06.09.21258643v1">MedRxiv</a>, we did genome-wide association studies (GWAS) on 33 different rare diseases. For three of those rare diseases, our GWAS was the first-ever done on those conditions. So the unique features of 23andMe’s research database allowed us to find the results included in our study. Another unique feature is that through additional surveys, we can also find associations of rare diseases with other traits/diseases. For example, <a href="https://blog.23andme.com/23andme-research/insights-from-ipf-study/">early insights</a> from our IPF study show that IPF patients are more likely to report having gastrointestinal reflux, shortness of breath, depression, and anxiety. 
<h6>What are you currently working on?</h6>
On the rare disease front, we are continuing to recruit IPF and Systemic sclerosis patients for our ongoing studies. We are also studying genetic associations for more diseases, as our cohort keeps growing. Outside of that, my team and I are working on trying to improve disease risk prediction, specifically on how to make genetic risk predictions accurate for all populations, and how to combine genetic and non-genetic data for risk prediction.
<h6>Have you learned anything interesting from your own 23andMe results?</h6>
I’ve never been a regular coffee drinker, even in graduate school, when many people are heavy coffee drinkers. Turns out I’m genetically less likely than average to drink caffeine, according to my 23andMe Caffeine  Consumption Wellness report! 
 
&nbsp;

Talking About Rare Disease with Senior Scientist Suyash Shringarpure

Editor&#8217;s Note: This post was updated 1/5/2022 with video comments from some of our customers. 
We’ve made some important updates to give customers greater control over tailoring their product experience so it more accurately reflects their gender.
23andMe now allows customers to distinguish between their sex assigned at birth and their gender. This allows all customers, but especially our transgender and/or non-binary customers, to have their gender accurately reflected in relevant product features, during their interactions with other customers they choose to make connections with, and if they choose to participate in DNA Relatives.
Current customers can take advantage of these updates by adding their gender and preferred relationship labels in their <a href="https://you.23andme.com/user/">Account Settings</a>.
<h6>Why have we made these changes?<img loading="lazy" decoding="async" class="alignright wp-image-29099 size-full" src="https://blog-api.23andme.com/wp-content/uploads/2021/08/account-gender-settin-page.png" alt="" width="236" height="512" srcset="https://blogcms.23andme.com/wp-content/uploads/2021/08/account-gender-settin-page.png 236w, https://blogcms.23andme.com/wp-content/uploads/2021/08/account-gender-settin-page-138x300.png 138w" sizes="auto, (max-width: 236px) 100vw, 236px" /></h6>
As part of our commitment to <a href="https://www.23andme.com/diversity-equity-inclusion">diversity, equity, and inclusion</a>, we are continually improving our product to reflect the diversity of all of our customers. This particular update was in response to customers who want their 23andMe profiles to more accurately reflect their gender. Not only that, but it&#8217;s the right thing to do. Our trans and non-binary customers have every right to see themselves reflected accurately in their 23andMe experience. And we want them to be able to participate in all of the features 23andMe offers safely and as their full, authentic selves.
<h6>What has changed?</h6>
After consulting our 23andMe LGBTQ+ Employee Resource Group and a focus group of transgender customers, 23andMe has added the option for customers to provide their gender (including a non-binary option), in addition to their birth sex, during account registration and in their Account Settings. 
If a customer chooses to opt in to research, their gender may be included, but it is always de-identified from their genetic information. Additionally, if they indicate their gender is not the same as their birth sex, they will receive additional messaging about their health reports.
Customers can also now decide if they would like to have masculine, feminine, or gender-neutral relationship labels (e.g., brother, sister, or sibling) shown to their connections and DNA relatives (if they choose to opt into these features).
23andMe will continue to use a customer&#8217;s birth sex as a part of our laboratory quality control steps. This is because if someone’s self-reported sex doesn’t match what we’ve determined from our analysis of their DNA, we want to make sure there wasn’t an error in processing. We will also continue to use a customer&#8217;s birth sex to help us deliver or interpret results for certain health, wellness, and traits topics.
All of this information can be changed at any time in a user&#8217;s Account Settings.
We hope these changes will start to make our product more inclusive for our transgender and non-binary customers. As more research becomes available, for example on how hormone replacement therapy may affect risk estimates, we hope to keep improving our product so that it is more relevant for these customers. We also know we have more work to do (for example, for our intersex customers) to make sure everyone has the opportunity to access, understand, and benefit from the human genome.
More reading:
<ul>
<li aria-level="1"><a href="https://customercare.23andme.com/hc/en-us/articles/360010964373-How-23andMe-uses-your-self-reported-Sex">How 23andMe Uses Your Self-Reported Sex</a></li>
<li aria-level="1"><a href="https://blog.23andme.com/23andme-research/how-was-your-sex-determined-it-might-be-a-lot-more-complicated-than-you-think/">How was your sex determined? It might be a lot more complicated than you think</a></li>
<li aria-level="1"><a href="https://blog.23andme.com/articles/diversity-equity-inclusion">23andMe’s Commitment to Diversity, Equity &amp; Inclusion</a></li>
</ul>


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<iframe loading="lazy" title="For Every Me" width="500" height="281" src="https://www.youtube.com/embed/0VbKLmkeVSc?feature=oembed" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>
</div></figure>

Making 23andMe More Inclusive for All Genders

By Daniella Coker, MPH, and Janie Shelton, Ph.D.*
Several studies show the three COVID-19 vaccines being used in the United States — from Johnson &amp; Johnson (J&amp;J), Moderna, and Pfizer — are safe<a href="https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/safety-of-vaccines.html">1,</a>2 and effective2,<a href="https://www.cdc.gov/coronavirus/2019-ncov/vaccines/effectiveness/work.html">3</a>  and offer the best hope to beat the pandemic.2,4 And as so many of us have gotten vaccinated, it’s impossible not to notice that people react differently to the vaccines. Many people report having no reaction, while others feel sick enough to stay home in bed. 23andMe researchers wanted to know more about why. Is it due to the type of vaccine, our age, or something else?
To learn more about these differences we analyzed the data from more than 100,000 23andMe consented research participants and found that the second in the two-shot vaccine from Moderna produced the strongest reactions. We also learned that younger people and women tended to react more to the vaccine than others.
<h2>Get Vaccinated</h2>
But before going into what our researchers found, we should be clear: The side effects of vaccines are minimal, while the risks from the virus caused by COVID-19 are severe. This was further confirmed by new <a href="https://www.cdc.gov/mmwr/volumes/70/wr/mm7032e4.htm?s_cid=mm7032e4_w">data from the CDC</a>.  More than 35 million people in the United States have contracted the virus caused by COVID-19, and 614,000 of them have died. Even with the emerging Delta variant cases, the most significant risk is remaining unvaccinated. We encourage people to take the advice of healthcare professionals, the <a href="https://www.who.int/emergencies/diseases/novel-coronavirus-2019/covid-19-vaccines/advice">World Health Organization</a>, state and local public health officials, and the CDC and get vaccinated. 
23andMe’s researchers wanted to examine differences in how sick people felt after receiving the vaccines. Now that more than half the U.S. population has been fully vaccinated and about 60 percent have had at least one shot,<a href="https://covid.cdc.gov/covid-data-tracker/#vaccinations">5</a> our scientists wanted to explore how people react differently to different vaccines and what factors may influence those differences. This study does not look at adverse reactions but categorizes how people felt after they were vaccinated and compares the degree of “feeling sick” between three different vaccines.
For 23andMe’s study, consented research participants were asked three questions: (1) What was their most recent COVID-19 vaccination? (2) What symptoms, if any, did they experience? and (3) How sick did they feel afterward.
Most research participants reported that their most recent vaccination was their second dose of either the Pfizer (44%) or Moderna (38%) vaccine.

 <figure class="wp-block-image size-large is-style-default"><img loading="lazy" decoding="async" width="260" height="167" src="https://blogcms.23andme.com/wp-content/uploads/2021/08/sample-size.png" alt="" class="wp-image-29110"/></figure>
 
Approximately half of respondents didn’t feel sick, 40% felt a little or somewhat ill, and 10% felt very or extremely sick. And to be clear, “feeling sick” as a reaction to the shot is not the same as being clinically sick from the virus and requiring hospitalization. 23andMe scientists sought to describe and characterize this wide range of reactions to the COVID-19 vaccines.
Here are some of the key findings:
<h2>The second Moderna shot seemed to produce the strongest reactions</h2>
Compared to the other vaccines, it was those people with a second dose Moderna vaccination who most often reported experiencing any symptoms (85%), and most often reported feeling either very or extremely sick (18%) after their vaccination. Again, these differences were not related to clinical outcomes. In other words, these are relatively modest reactions to the vaccines, but the vaccines still offered strong protection against the virus. In addition, these reactions were generally only for a couple of days after the vaccination. Whereas the severity of COVID-19 infections includes potential weeks or months of hospitalization or death. In addition, scientists still don’t fully know the timeline for so-called COVID-19 “longhaulers,” people dealing with lingering symptoms long after being infected.

 <figure class="wp-block-image size-large is-style-default"><img loading="lazy" decoding="async" width="512" height="314" src="https://blogcms.23andme.com/wp-content/uploads/2021/08/vaccine-reaction-by-type.png" alt="" class="wp-image-29111" srcset="https://blogcms.23andme.com/wp-content/uploads/2021/08/vaccine-reaction-by-type.png 512w, https://blogcms.23andme.com/wp-content/uploads/2021/08/vaccine-reaction-by-type-300x184.png 300w" sizes="auto, (max-width: 512px) 100vw, 512px" /></figure>
 
Fatigue, pain at the injection site, and muscle/body aches were the most commonly reported symptoms for all vaccine types. Yet, for every symptom (except nausea), a larger portion of Moderna’s second-dose recipients reported experiencing that symptom compared to recipients of other vaccines.

 <figure class="wp-block-image size-large is-style-default"><img loading="lazy" decoding="async" width="512" height="106" src="https://blogcms.23andme.com/wp-content/uploads/2021/08/vaccine-matrix.png" alt="" class="wp-image-29112" srcset="https://blogcms.23andme.com/wp-content/uploads/2021/08/vaccine-matrix.png 512w, https://blogcms.23andme.com/wp-content/uploads/2021/08/vaccine-matrix-300x62.png 300w" sizes="auto, (max-width: 512px) 100vw, 512px" /></figure>
 
And in logistic regression models controlling for key demographics (age, sex, BMI, ethnicity, education, and history of COVID-19 infection), having received a second Moderna shot was significantly associated with 3x odds of experiencing any symptom and nearly 1.5x odds of feeling very or extremely sick (as compared to J&amp;J).
So, you are not imagining things &#8212; if you got the Moderna 2nd dose and felt “under the weather”, you are not alone. A lot of people did (nearly 1 in 5), but for <a href="https://www.cdc.gov/vaccines/covid-19/info-by-product/moderna/moderna-faqs.html#vaccine-safety-efficacy">94.1% effectiveness</a> against COVID-19, we are all applauding those of you who suffered through a few days of discomfort for your and the greater good.
<h2>A history of COVID-19 infection associated with feeling sicker </h2>
You may have heard the rumor that people who have had COVID-19 are more likely to feel sick after receiving a vaccine. According to 23andMe data, that seems to be true — a larger proportion of consented research participants previously infected with COVID-19 reported feeling sick for every degree of sickness (from “a little” to “extremely”) compared to those not previously infected with COVID-19. In fact, only a third of participants with a previous infection experienced no symptoms from their vaccine, compared to half of those without a COVID-19 history.

 <figure class="wp-block-image size-large is-style-default"><img loading="lazy" decoding="async" width="512" height="285" src="https://blogcms.23andme.com/wp-content/uploads/2021/08/How-Sick-do-you-feel.png" alt="" class="wp-image-29113" srcset="https://blogcms.23andme.com/wp-content/uploads/2021/08/How-Sick-do-you-feel.png 512w, https://blogcms.23andme.com/wp-content/uploads/2021/08/How-Sick-do-you-feel-300x167.png 300w" sizes="auto, (max-width: 512px) 100vw, 512px" /></figure>
 
Even after controlling for the key demographic variables listed above, having a history of a COVID-19 infection increased your odds of experiencing any symptoms or feeling very/extremely sick after your vaccination, both by about 30%.
<h2>More and stronger reactions for women and younger individuals</h2>
Women were more likely to have any symptoms, have more whole body (systemic) symptoms, and generally feel sicker following their vaccination compared to men.  

 <figure class="wp-block-image size-large is-style-default"><img loading="lazy" decoding="async" width="512" height="314" src="https://blogcms.23andme.com/wp-content/uploads/2021/08/vaccin-reaction-by-sex.png" alt="" class="wp-image-29114" srcset="https://blogcms.23andme.com/wp-content/uploads/2021/08/vaccin-reaction-by-sex.png 512w, https://blogcms.23andme.com/wp-content/uploads/2021/08/vaccin-reaction-by-sex-300x184.png 300w" sizes="auto, (max-width: 512px) 100vw, 512px" /></figure>
 
In fact, after controlling for potential confounders, women were almost twice as likely as men to have felt very or extremely ill.
Similar trends were observed for younger individuals when compared to older folks. Those 40 years of age and younger experienced between 2 and 3 whole-body symptoms on average, and nearly a quarter felt very or extremely sick. By contrast, those at least 75 years old experienced between 0 and 1 whole-body symptoms on average, and only 4% felt very ill.

 <figure class="wp-block-image size-large is-style-default"><img loading="lazy" decoding="async" width="512" height="315" src="https://blogcms.23andme.com/wp-content/uploads/2021/08/vaccine-reaction-by-age.png" alt="" class="wp-image-29109" srcset="https://blogcms.23andme.com/wp-content/uploads/2021/08/vaccine-reaction-by-age.png 512w, https://blogcms.23andme.com/wp-content/uploads/2021/08/vaccine-reaction-by-age-300x185.png 300w" sizes="auto, (max-width: 512px) 100vw, 512px" /></figure>
 
These relationships between sex, age, and vaccine reaction held up, even after controlling for potential confounders.
<h2>How do the COVID-19 vaccines work?</h2>
The COVID vaccines teach your immune system to recognize and respond to the virus that causes COVID-19. The vaccines introduce genetic instructions to make a harmless protein that is unique to the virus. This triggers a two-step immune response: a first, more immediate and non-specific reaction (the innate immune response), followed by a more gradual, pathogen-specific reaction (the adaptive immune response).<a href="https://www.healio.com/hematology-oncology/learn-immuno-oncology/the-immune-system/the-innate-vs-adaptive-immune-response">6</a>
But why do some people feel very sick from their COVID-19 vaccine, and others don’t feel sick at all? Scientists aren’t quite sure why that is. However, data points to the immune system.
<h2>What does my vaccine reaction mean?</h2>
Trends identified in 23andMe data support what the vaccine clinical trials and other studies have observed — that certain groups of people are more likely to have felt sicker from their COVID-19 vaccination. These include:
<ul>
<li aria-level="1">Women<a href="https://www.cdc.gov/mmwr/volumes/70/wr/mm7008e3.htm">7</a></li>
<li aria-level="1">Younger people<a href="https://www.cdc.gov/mmwr/volumes/70/wr/mm7008e3.htm">7,</a> 8,9,<a href="https://www.cdc.gov/vaccines/covid-19/info-by-product/janssen/reactogenicity.html">10</a></li>
<li aria-level="1">Recipients of a second dose vaccine (compared to their first dose)8,9,<a href="https://jamanetwork.com/journals/jama/fullarticle/2778441">11</a></li>
</ul>
Women, for instance, seem to have stronger immune reactions than men. Research for other types of vaccinations, such as for influenza, yellow fever, and hepatitis, showed that women produce more infection-fighting antibodies than men following vaccination.<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7438701/">12</a> Hormonal and genetic differences between the sexes may also play a role in how the immune systems of men and women respond differently to vaccinations. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7438701/">12,</a><a href="https://www.sciencedirect.com/science/article/pii/S1028455920302175">13</a>
As we age, our immune systems tend to weaken.<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3901832/">14</a> This may explain why younger adults were generally more likely to report a larger number of and more severe symptoms following their vaccination compared to older adults, as seen in data from 23andMe consented research participants and elsewhere, including the vaccines’ clinical trials.<a href="https://www.cdc.gov/mmwr/volumes/70/wr/mm7008e3.htm">7,</a>8, 9, <a href="https://www.cdc.gov/vaccines/covid-19/info-by-product/janssen/reactogenicity.html">10</a>
By the time you receive a second dose, your body has already become primed to recognize and respond to the virus that causes COVID-19, and as a result your immune system responds faster and stronger. <a href="https://www.gavi.org/vaccineswork/why-vaccine-side-effects-might-be-more-common-people-whove-already-had-covid-19">15,</a><a href="https://www.nationalgeographic.com/science/article/why-vaccine-side-effects-really-happen-and-when-you-should-worry">16</a> This likely explains why people tend to have more severe reactions to their second dose compared to their first dose.
And it may also be why 23andMe researchers observe that people with a history of COVID-19 infection also feel more ill following their most recent vaccination, compared to those without a prior infection. The virus itself is an additional trigger for your immune responses to kick in. Several small studies have found that people with a history of COVID-19 infection experienced symptoms more frequently<a href="https://www.medrxiv.org/content/10.1101/2021.01.29.21250653v1">17,</a><a href="https://covid.joinzoe.com/post/vaccine-after-effects-more-common-in-those-who-already-had-covid">18 </a>and had higher levels of antibodies after a first dose,<a href="https://jamanetwork.com/journals/jama/fullarticle/2777171">19</a> compared to those without a history of infection.
This analysis on over 100,000 individuals builds upon these findings, showing that a previous COVID-19 infection might not just be related to the number of symptoms experienced following a COVID-19 vaccination, but also the severity of these symptoms.
<h2>The COVID-19 vaccines are still effective, regardless of your vaccine-related reaction</h2>
Although there is some uncertainty regarding why some people experience more mild or severe symptoms following their COVID-19 vaccination, what we do know is this: the COVID-19 vaccines are effective, whether or not you felt sick after the vaccination.
Data from the vaccine trials showed that not everyone reported vaccine-related reactions; 23% from Pfizer, 18% from Moderna (second dose), and between 39% (younger adults) and 55% (older adults) from J&amp;J didn’t experience any systemic reactions.8,9,<a href="https://www.cdc.gov/vaccines/covid-19/info-by-product/janssen/reactogenicity.html">10</a> And this is coming from the same data that demonstrated how safe and effective these vaccines are.
Put another way: “Even if you don’t have an unpleasant reaction, the vaccines are still doing their job, because the real work of the immune system &#8211; and of the vaccines &#8211; takes place during the second, or adaptive phase of the immune response.”<a href="https://www.nationalgeographic.com/science/article/why-vaccine-side-effects-really-happen-and-when-you-should-worry">16</a>
<h2>What’s next?</h2>
Research is ongoing to understand why reactions to the COVID-19 vaccines differ and what these differences mean.  This work is part of our ongoing broad research into COVID-19 that has included studying how genetics plays a role in both the <a href="https://www.nature.com/articles/s41588-021-00854-7">susceptibility and severity of COVID-19</a> and looking at other aspects of the pandemic like its impact on <a href="https://blog.23andme.com/23andme-research/covid-impact-on-sleep/">sleep</a>, <a href="https://blog.23andme.com/23andme-research/stepping-back-up-amid-covid-19/">physical activity</a> and how it has <a href="https://blog.23andme.com/23andme-research/impact-disparities-of-covid-19/">hit some communities harder than others</a>. As part of this work, our scientists are preparing to run genetic analyses to help answer why individuals react differently to the vaccine and what those differences might mean.
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*The 23andMe COVID-19 research team includes Adam Auton, Adrian Chubb, Alison Fitch, Alison Kung, Amanda Altman, Andy Kill, Anjali Shastri, Antony Symons, Catherine Weldon, Chelsea Ye, Jason Tan, Jeff Pollard, Jey McCreight, Jess Bielenberg, John Matthews, Johnny Lee, Lindsey Tran, Maya Lowe, Michelle Agee, Monica Royce, Nate Tang, Pooja Gandhi, Raffaello d’Amore, Ruth Tennen, Scott Dvorak, Scott Hadly, Stella Aslibekyan, Sungmin Park, Taylor Morrow, Teresa Filshtein Sonmez, Trung Le, and Yiwen Zheng.

A logo for 23andMe's COVID-19 Research Study

COVID-19 Vaccine Reaction Data

For the uninitiated the mere idea of smearing a sticky blackish sludge of brewer&#8217;s yeast on a piece of toast and then eating it for breakfast might trigger a wee bit of nausea, and yet there are people in this world who love Marmite.
Why?
<h6>Taste Preference</h6>
Like many of the other <a href="https://www.bbc.co.uk/programmes/b007zpll">Big Questions</a> we face in this life, the answer is complicated. And then there&#8217;s the fact that Marmite is one of those polarizing foods you either love or hate. 
We&#8217;re into science, and we like to ask probing and even provocative questions here at 23andMe. So we wanted to know if we could learn a little about whether genetics might play a role in your choice of breakfast spreads. <img loading="lazy" decoding="async" src="https://blog-api.23andme.com/wp-content/uploads/2021/08/Marmite-300x220.png" alt="Pieces of toast with Marmite spread over them." class="alignright wp-image-29103 size-medium" width="300" height="220" srcset="https://blogcms.23andme.com/wp-content/uploads/2021/08/Marmite-300x220.png 300w, https://blogcms.23andme.com/wp-content/uploads/2021/08/Marmite-768x562.png 768w, https://blogcms.23andme.com/wp-content/uploads/2021/08/Marmite-1024x750.png 1024w, https://blogcms.23andme.com/wp-content/uploads/2021/08/Marmite-880x644.png 880w, https://blogcms.23andme.com/wp-content/uploads/2021/08/Marmite-1180x864.png 1180w" sizes="auto, (max-width: 300px) 100vw, 300px" />
Genetics, after all, factors into our taste preferences.  Whether it&#8217;s liking <a href="https://blog.23andme.com/health-traits/traits-never-looked-better/">Salty v. Sweet</a> snacks, or have an aversion to <a href="https://blog.23andme.com/health-traits/traits-never-looked-better/">Bitter Taste</a>, or a dislike of <a href="https://blog.23andme.com/health-traits/23andme-adds-four-new-trait-reports/">Cilantro</a>, your genes pay at least a small role. And don&#8217;t get us started on &#8220;<a href="https://blog.23andme.com/health-traits/tasty-genetics/">supertasters</a>.&#8221; These kinds of culinary inclinations are determined by a complex interaction between your environment, your lifestyle, and, yes, your DNA. 
So what about Marmite? (We&#8217;re going to leave Vegemite, Marmite&#8217;s even more robust Aussie cousin, in the pantry for now.)
<h6>What About the Genetics?</h6>
Genetics explains some of the appeal of Marmite, according to a new genome-wide association study by researchers at 23andMe. 
Looking at data from more than 100,000 23andMe customers of European descent who consented to participate in research — and who know what the heck Marmite is — Peter Chisnell, PhD., a 23andMe Health R&amp;D scientist found three genetic variants associated with &#8220;loving&#8221; Marmite. 
In follow-up analysis, Peter looked at the area in the genome where we saw the strongest genetic association. It is near a gene related to olfaction, a key to our sense of taste. The SNP is near the <a href="https://www.ncbi.nlm.nih.gov/gene/6496">SIX3 gene</a>, a &#8220;homeobox protein,&#8221; and acts like a master controller for the expression and regulation of a bunch of genes. 
“It&#8217;s a giant sledgehammer kind of gene that affects a lot of things,&#8221; said Peter. 
<h6>Smell and Taste</h6>
Large changes in its function have been shown to disrupt neurodevelopment in mice, including a part of their brain responsible for olfaction. We don&#8217;t really know exactly how these small genetic changes in people could explain differences in taste, but it’s plausible that changes in the sense of smell may make one more prone to like the salty savory flavor of Marmite. 
Along with the association found near the SIX3 homeobox gene, the study found an association near the gene OR12D1, an olfactory receptor. Finally, Peter’s analysis noted a significant single nucleotide polymorphism (SNP) associated with loving Marmite near the NRXN3 gene, which is involved in the nervous system, including behavioral traits like fear and empathy, but also tendencies toward addiction and obesity. 
What these all may or may not mean regarding a preference toward the salty-savory taste of Marmite is about as opaque as the dark syrupy spread itself. After all, our sense of taste is a complex process. 
Taste receptors on our tongue bind to a set of chemical compounds in food to recognize specific odorants or tastants and then sends that information to our brains. There are receptors for five types of tastes — sweet, sour, salty, bitter, and savory, also known as umami. Several different genes are essential for taste and smell. So, for example, the TAS1R and TAS2R gene group is involved in the perception of sweet, umami, and bitter perception. The hundreds of genes that are part of the olfactory receptor gene group also play a role. 
<h6>The Cultural Story </h6>
Beyond the biology involved in taste is a whole slew of cultural and environmental factors that go into what each of us likes and doesn&#8217;t like to eat. 
We see a little of that in 23andMe&#8217;s study because we also looked beyond genetics. The 23andMe researchers broke down individuals by sex and also by country, not just where they currently reside but where they were born. Men were more likely to love Marmite than women, for instance. The difference between men and women isn&#8217;t likely explained by the genetic associations we analyzed, Peter said. The data also gets interesting when you break it down geographically. 
This offers a great example of how culture also plays a role in taste preference. Genetics can&#8217;t really explain the differences in why some countries have more Marmite lovers than others. This is because countries have about the same proportion of people who are genetically predisposed to liking Marmite.
As you would expect, the researchers found that most people who knew about Marmite lived in Commonwealth countries with strong ties to the UK. And unsurprisingly, some of those same countries were where you found the most Marmite lovers — New Zealand, South Africa, Australia, and the UK. But also among the countries that ranked highest for loving it were Russia and Turkey.
Among those places that ranked highest for hating Marmite were the US, Canada, and Ireland.
&#8220;We don&#8217;t have a great biological mechanism to explain those differences,&#8221; said Peter. &#8220;The cultural story seems more plausible to me than a biological explanation.&#8221;
<h6>An Acquired Taste</h6>
Food preferences and acquired tastes are greatly influenced by the culture we live in. 
And why do you have more Marmite haters in Canada, Ireland, and the US? There are no discernable genetic differences to explain that. 
Interestingly, none of the genetic associations we found for loving Marmite were in the genes associated with bitter taste receptors. Nor did we replicate any of the associations in the only other genome-wide association study on Marmite. 
And yes, our GWAS is actually not the first one on Marmite. A few years back, the company that has made the spread since the first World War launched the <a href="https://www.marmite.co.uk/the-gene-project.html">Marmite Gene Project</a>. In collaboration with another company, they ran a <a href="https://www.dnafit.com/downloads/MarmiteGenetics_WhitePaper_Final.pdf">GWAS using just 261</a> people. That tiny study found 15 SNPs associated with Marmite preference. But the researchers acknowledged that the study lacked statistical power. None of the SNPs or genes identified in that study were replicated in our own.
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A black and white image of toast with Marmite spread on it

The Genetics of Loving or Hating Marmite

By Alexa Reynoso, 23andMe Associate Scientist, Genetic Epidemiology
The use of electronic cigarettes, or vaping, is associated with several unhealthy behaviors and traits particularly among young people, according to new data from 23andMe.
But the data merely notes an association between vaping and those behaviors and traits, it’s not an indication of causation. Unlike the long-established research that links smoking to cancer, disability, and death, there remains a dearth of data on the health effects of vaping. Some recent studies have linked vaping to deleterious effects on the lungs. And last year a Stanford study found an association between<a href="https://www.jahonline.org/article/S1054-139X(20)30399-2/fulltext#secsectitle0050"> risk for COVID-19 and vaping</a> among young people.
<h2>Health Impacts</h2>
Scientists are still at the beginning of understanding the long-term health implications of e-cigarettes. At 23andMe we’ve only been collecting data on vaping for about a year. In the summer of 2020, our researchers added new questions to our smoking survey to account for vaping and e-cigarette use.
By looking at data we’ve gathered from the more than 76,000 customers who consented to participate in research and responded to our smoking survey, we were able to explore demographic and other characteristics of e-cigarette users. We were then able to compare people who vape to those who smoke just cigarettes, or who both smoke and vape (dual users), and those who don’t smoke or vape at all. (Note: This is not a representative sample of the entire 23andMe population, nor is it representative of national numbers. The CDC estimates that 4.5 percent of adults in the United States vape.¹ Among 23andMe research participants, only about .2 percent, or 19,000 individuals, reported being regular e-cigarette users. The sample for this research is composed only of respondents to our Smoking survey.)

 <figure class="wp-block-image size-large is-style-default"><img loading="lazy" decoding="async" width="1024" height="683" src="https://blogcms.23andme.com/wp-content/uploads/2021/08/GettyImages-975633438-1024x683.jpg" alt="" class="wp-image-29075" srcset="https://blogcms.23andme.com/wp-content/uploads/2021/08/GettyImages-975633438-1024x683.jpg 1024w, https://blogcms.23andme.com/wp-content/uploads/2021/08/GettyImages-975633438-300x200.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2021/08/GettyImages-975633438-768x512.jpg 768w, https://blogcms.23andme.com/wp-content/uploads/2021/08/GettyImages-975633438-880x587.jpg 880w, https://blogcms.23andme.com/wp-content/uploads/2021/08/GettyImages-975633438-1180x787.jpg 1180w" sizes="auto, (max-width: 1024px) 100vw, 1024px" /></figure>
 
<h2>What are E-Cigarettes?</h2>
Before we get into what the data showed, it’s worth understanding a bit more about how e-cigarettes work.
Introduced in 2004,² e-cigarettes were first touted as a less harmful way for smokers to kick their habit. Unlike with cigarettes, users of e-cigarettes are not inhaling smoke. They are inhaling a smoke-like aerosol, or vapor, produced when these devices heat a liquid that usually contains nicotine but also other potentially harmful substances.¹
While vaping may be helping some who are trying to kick their smoking habit, it may also be a gateway for others starting a nicotine addiction. This could be particularly relevant for young people. Juul Labs recently paid a $40 million settlement to the state of North Carolina for allegedly targeting youth in its marketing. According to a study on vaping trends published last year in the<a href="https://www.nejm.org/doi/full/10.1056/NEJMc1910739"> New England Journal of Medicine</a>, it was noted that an increase in vaping among young people between 2018 and 2019 was “the largest of any substance tracked” in the last four decades.
<h2>23andMe’s Data on Vaping Among Young People</h2>
In looking at our data, 23andMe researchers found that those between the ages of 18-30 were more likely to vape.

 <figure class="wp-block-image size-large is-style-default"><img loading="lazy" decoding="async" width="512" height="385" src="https://blogcms.23andme.com/wp-content/uploads/2021/08/Figure-1-E-cigs.png" alt="" class="wp-image-29097" srcset="https://blogcms.23andme.com/wp-content/uploads/2021/08/Figure-1-E-cigs.png 512w, https://blogcms.23andme.com/wp-content/uploads/2021/08/Figure-1-E-cigs-300x226.png 300w" sizes="auto, (max-width: 512px) 100vw, 512px" /></figure>
 
Not only were young people more likely to vape, but these younger users of e-cigarettes were also more likely to use them at a higher frequency. Essentially, they take more “puffs” each day than older people in the study who vape. These findings are in accordance with those of the CDC.¹
Beyond being younger, individuals who are dual users — they smoke and vape — come from locations with a slightly lower median household income when compared to cigarette-only users, e-cigarette only users, and those that used none. Lastly, when comparing the four use groups in regards to years of education, research participants that do not smoke or vape tend to have obtained the highest amount of education.
Our researchers also stratified by sex and ethnicity but did not find strong differences as they did with age.
<h2>23andMe Insights</h2>
While we did not look specifically at health outcomes, we did look at various associations with unhealthy behavior and traits.
We found associations between vaping and such things as being more likely to be stressed, depressed, and anxious compared to those who do not vape. People who vape also were more likely to be diagnosed with bi-polar disorder. We saw associations between people who vape being more likely to report poor overall health, low life satisfaction as well as being less likely to exercise and eat right. People who vape in our data also were more likely to eat less fruit, drink more caffeine, need higher doses of pain medication, and are less likely to be a morning person. (More associations found with e-cigarette use within the 23andMe database are summarized in Figure 1. )

 <figure class="wp-block-image size-large is-style-default"><img loading="lazy" decoding="async" width="512" height="418" src="https://blogcms.23andme.com/wp-content/uploads/2021/08/E-cig-associations.png" alt="" class="wp-image-29096" srcset="https://blogcms.23andme.com/wp-content/uploads/2021/08/E-cig-associations.png 512w, https://blogcms.23andme.com/wp-content/uploads/2021/08/E-cig-associations-300x245.png 300w" sizes="auto, (max-width: 512px) 100vw, 512px" /></figure>
 

 <figure class="wp-block-image size-large is-style-default"><img loading="lazy" decoding="async" width="1024" height="564" src="https://blogcms.23andme.com/wp-content/uploads/2021/08/Table-1-E-Cigs-1024x564.png" alt="" class="wp-image-29095" srcset="https://blogcms.23andme.com/wp-content/uploads/2021/08/Table-1-E-Cigs-1024x564.png 1024w, https://blogcms.23andme.com/wp-content/uploads/2021/08/Table-1-E-Cigs-300x165.png 300w, https://blogcms.23andme.com/wp-content/uploads/2021/08/Table-1-E-Cigs-768x423.png 768w, https://blogcms.23andme.com/wp-content/uploads/2021/08/Table-1-E-Cigs-880x485.png 880w, https://blogcms.23andme.com/wp-content/uploads/2021/08/Table-1-E-Cigs-1180x650.png 1180w, https://blogcms.23andme.com/wp-content/uploads/2021/08/Table-1-E-Cigs-271x149.png 271w, https://blogcms.23andme.com/wp-content/uploads/2021/08/Table-1-E-Cigs-372x204.png 372w, https://blogcms.23andme.com/wp-content/uploads/2021/08/Table-1-E-Cigs-574x315.png 574w, https://blogcms.23andme.com/wp-content/uploads/2021/08/Table-1-E-Cigs-980x539.png 980w, https://blogcms.23andme.com/wp-content/uploads/2021/08/Table-1-E-Cigs.png 1274w" sizes="auto, (max-width: 1024px) 100vw, 1024px" /></figure>
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An environment-wide association study of cigarette smokers in our database was also conducted to determine if there are any fundamental differences between research participants that smoke e-cigarettes versus tobacco cigarettes.
<h2>Correlations</h2>
Our results indicated that the two groups are much more similar than they are different. Similar to the e-cigarette results, we saw that smokers were much more likely to experience depression and anxiety. Both cigarette and e-cigarette users also reported a lower general health score. Other interesting correlations (see Figure 2.) were that cigarette smokers tend to drink more alcohol  and tend to be more hot-headed.

 <figure class="wp-block-image size-large is-style-default"><img loading="lazy" decoding="async" width="512" height="414" src="https://blogcms.23andme.com/wp-content/uploads/2021/08/E-cigs-associations-2.png" alt="" class="wp-image-29094" srcset="https://blogcms.23andme.com/wp-content/uploads/2021/08/E-cigs-associations-2.png 512w, https://blogcms.23andme.com/wp-content/uploads/2021/08/E-cigs-associations-2-300x243.png 300w" sizes="auto, (max-width: 512px) 100vw, 512px" /></figure>
 

 <figure class="wp-block-image size-large is-style-default"><img loading="lazy" decoding="async" width="1024" height="395" src="https://blogcms.23andme.com/wp-content/uploads/2021/08/Table-2-E-cigs-1024x395.png" alt="" class="wp-image-29093" srcset="https://blogcms.23andme.com/wp-content/uploads/2021/08/Table-2-E-cigs-1024x395.png 1024w, https://blogcms.23andme.com/wp-content/uploads/2021/08/Table-2-E-cigs-300x116.png 300w, https://blogcms.23andme.com/wp-content/uploads/2021/08/Table-2-E-cigs-768x297.png 768w, https://blogcms.23andme.com/wp-content/uploads/2021/08/Table-2-E-cigs-880x340.png 880w, https://blogcms.23andme.com/wp-content/uploads/2021/08/Table-2-E-cigs-1180x456.png 1180w, https://blogcms.23andme.com/wp-content/uploads/2021/08/Table-2-E-cigs.png 1274w" sizes="auto, (max-width: 1024px) 100vw, 1024px" /></figure>
 
Although researchers uncovered correlations between smoking and certain demographic variables, it should be noted that correlation does not equal causation. Proving that certain behaviors or demographics cause another is quite difficult; meaning that we can’t say if someone isn&#8217;t a morning person they must be an e-cigarette user. In order to come to these conclusions, researchers must conduct years of extensive research consisting of numerous rigorous trials and studies.
That’s not to say what we uncovered so far is trivial, but rather we are on the right track. We are still just beginning to understand the long-term health implications of e-cigarettes. Over time, however, with the power of our large research cohort and scientific community, we could uncover more novel associations between e-cigarette use and long-term health effects.
23andMe customers who would like to contribute to our research efforts surrounding e-cigarette usage can take the survey <a href="https://you.23andme.com/research/surveys/tobacco/">here</a>. Not yet a customer? Find out more <a href="https://www.23andme.com/compare-dna-tests/?spt=spt">here</a>.
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<h2>References</h2>
<ol>
<li>“About Electronic Cigarettes (E-Cigarettes).” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 28 Apr. 2021, www.cdc.gov/tobacco/basic_information/e-cigarettes/about-e-cigarettes.html.</li>
<li>Cobb, Nathan K., et al. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2978165/">“Novel Nicotine Delivery Systems and Public Health: The Rise of the ‘E-Cigarette.’</a>” American Journal of Public Health, vol. 100, no. 12, 2010, pp. 2340–2342., doi:10.2105/ajph.2010.199281.</li>
</ol>

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