Genetics, Puberty and African American Girls

AA MenarcheSeveral studies have shown that certain girls, particularly African-American girls, experience puberty earlier than others, but there’s an ongoing debate about what that might mean.

There are a number of reasons why some girls begin puberty earlier than others. Girls who are heavier tend to enter puberty earlier than thinner girls, while there are also disorders that can trigger “precocious puberty”— or puberty before age eight. Environmental factors, such as nutrition and certain chemicals, also can play a role.  Understanding the genetic components that influence when a girl begins menstruating — also known as her age at menarche (“men-AR-kee”) — could also help scientists better understand the genetic factors behind diseases associated with early puberty, including type 2 diabetes and breast cancer.

But to date, the scientific community has all but overlooked a core population that is perhaps most at risk. Today, African-American women tend to begin menstruating four to six months earlier than girls of European descent. Later in life African-American women also have a higher risk for obesity, hypertension, and metabolic disorders including diabetes. These two trends could be related and genetic factors could be a common denominator.

A new study of African-American women looked specifically at genetic variations contributing to  age at menarche. The research, done by a multi-institutional team of scientists, crunched data from 15 different studies, which included information from over 18,000 women.

Their findings indicate differences in DNA that could help scientists better understand the genetics of menarche timing in all women, as well as the development of diseases associated with early menarche.

We’ve written before about the importance of considering ancestry when analyzing trends in disease. Certain diseases are more prevalent in certain populations. For instance, African-American men are more likely to develop and die from prostate cancer than people of European descent.  African Americans also tend to be at higher risk for type 2 diabetes, while people of European descent are at higher risk of the heart rhythm disorder atrial fibrillation.

Given the difference in risk it seems imperative that researchers investigate a diversity of populations to better understand the genetic factors behind these diseases. Yet research on populations with non-European ancestry continues to lag.

In this case study, the researchers performed a meta-analysis of existing research to search for DNA variants associated with earlier menarche in African-American women and then compared their results to data from women of European descent. The variants, called SNPs (or single-nucleotide polymorphisms), can account for some of the differences in biological traits, in this case early menarche, between two individuals. These variants in turn can help scientists identify the genes and biological mechanisms controlling menarche timing.

Out of 42 SNPs associated with age at menarche in European women, 25 were also associated with the trait in African-American women, bolstering the evidence that these genes genetic variants are tied to menarche timing. However, they also found variants in eight regions of the genome that were more strongly associated with age at menarche in African-American women than in European-American women. Many of these regions contain genes that influence obesity, underscoring the link between body fat and early menarche. Other regions include genes associated with breast and other cancers.

Although this is the largest and most comprehensive study of its kind, the total number of data samples of African-American women available to the researchers was still fewer than are now available for European-American women. And yet the study demonstrates an important fact: by studying diverse ethnicities, scientists can refine their understanding of the role genes play in all populations.


  • LMar

    I was nine when I started mine. I am AA. Though, I was extremely skinny, and i’m still young, in my 20s.

    • http://blog.23andme.com/ MIKE CONLON

      I’m glad your weight is under control. The article can be misleading in that one can interpret it as saying that if a girl is overweight, they are more likely to be “early.” It doesnt say this; it says that the same gene or gene group controls both menarche and weight. Thus, in many cases the two are tied together in a girls life. But a genetic factor doesn’t always mean the same thing in everyone; this is what the phrase “genetics isnt destiny” means.
      Also, the scientific understanding of genetics is still very incomplete. Its good to see that scientists are studying issues that affect African American girls-knowledge is power. Knowledge about yourself gives you the potential to better control your destiny

      • Papi

        I thought all little girl’s problems were caused from drinking milk because they feed cows stuff to make them produce more milk and………….I don’t know where I’m going with this……

        • SciGuy

          No, you are going to the right direction:
          rGBH (BST) are artificial pregnancy hormones administered to dairy cows to make their body think it is pregnant and produce more milk. Not only do they create havoc with a young girls hormone development they create gender-bending and sexual mis-orientation in developing fetuses and younger children, ages 1-5.
          These and other toxic chemicals were approved for consumer consumption by the EPA & FDA review and approval boards who are staffed by short-term employees from the very companies submitting for approval. No government employees watching out for your welfare: contract workers from the very companies making billions off products that destroy and kill.
          So keep “going” with this and keep thinking and keeping being the master of your own destiny.

        • bahona

          Genetically modified corn and soy also wreak havoc on our endrocrine/hormone system. Processed foods (inexpensive foods) are full of genetically modified corn & soy. Only the very wealthy (e.g., Mitt Romney) can afford to feed their children the organic-only diet that will keep them healthy.

  • Benita

    I was 15 when I started, I am northern European.

  • Maria

    I was 15, I am AA, or so I thought until I got my DNA analysis, it seems I am 59% AA, 38% European, and 1.9% Asian/Native American. I was super skinny at the time, hardly any bodyfat and very athletic.

  • Judy Foster

    I got boobs at eight, periods at 10 and menopause at 42. I’m nearly 70 now and according to a DNA test I am 100% european.

  • Doris Owusu

    I was 14 and slim. I am African and one of my daughters got it at 14 and second daughter at 10. Both girls are slim.

    • Che’

      This is a study about African Americans/Blacks and Europeans, not Africans.

      • Hermione

        Africans are just as the same as African-Americans, because African-Americans are of the same descent of africans.

  • warren

    Puberty is primarily influenced by hormones.

  • Aisha

    Here we go again!! founded on nothing but, speculation, I am African full blooded! I got my period at 14, have 5 kids, my last born is a girl, she is super skinny, with small boobs, no period yet and she is 13. I was skinny 50 years ago, still super skinny, breastfed each child for 2 years, never took contraceptive, my boobs are still good and I am very healthy, just returned back from Kabul for an assignment, I look 25 rather than 50. This is rubbish, nonsense !!

    • Vivian

      This article is not saying all African American women begin their periods early. It’s saying they are more likely to when compared to European Americans. It also looked at African American women and not African women. There could be a difference. But hey–congrats on looking young.

      • Papi

        Rubbish? Because it didn’t happen to you, it over-rides statistics from millions of people? Now “THAT’S” rubbish!

      • Sarah

        We can’t even have a scientific conversation, without being petty. I am European, and I hate it when African-Americans/Black and other cultures separate themselves from their ancestry. African-Americans are African, whether they were born here or there. Hence the name “African”-American. They have experienced the same slavery, segregation and discrimination that happened/happens here, over there. The African culture is beautiful and has enhanced every aspect of American culture, whether it be music, dance, art, food, fashion etc. I feel like cultures including African-American/Black sees the identifyer “African” as having a derogatory meaning. Can we get back to the topic please…?

    • sam hain

      Was your first kid at 15?

    • Ted

      Even if your ancestors came directly from Africa, you’re not “African full blooded!” Genetic studies of “REALLY, REALLY, REALLY African” African-Americans still only show 80-85% “African” DNA. Most modern Africans were still under the rule of a European colonial government until the mid-70s, so even they tend to have a little European or Arab blood thrown into the mix.

      You’re certainly old enough to make your own decisions, but you’re also old enough to read the article and not discount something simply because you don’t feel that it perfectly matches your experience.

  • John

    I remember reading a study years ago that in households with a father present, their daughters experienced menarche on average a year later than in households with no Dad present. Something to do with male phermones delaying menarche.

    • Helen Graft

      I read an article about that, too. I think it begins even earlier when there are males in the household who are not related by blood. I also read that they think certain relaxing products (popular w/in the African American population) influence the onset of early puberty. Other books/articles have also faulted chemicals leaching from hot plastics and detergents in addition to the food additives and hormones. With two young daughters (one of which was a heavy baby), it’s been hard to keep all those factors at bay, but I keep trying.

      • Helen Graft

        I was going to add that I was 12 when I began and I was average height, weight and am of mostly Northern European descent.

    • Lilith

      i read this too, that girls wirh absent fathers ‘menstruated’ earlier. and there is also known to be hormonal interplay between women living under the same roof synchronising menstruation. so probably there is so much more to this than genetic predisposition. plus we all catch up within around 5 years.

      so what, if any, is the significance of menstruation age when positive self image, approprtiate sexual education and emotional support are what we should be focusing on for the good health of our daughters.

  • Maureen Vincent

    I was 11 when I started. My sisters were ages 9 and 12 when they started. We are of European descent: Irish, English and French. Two of us were slim and one was slightly overweight. I am now 53 and went through menopause 4 years ago.

    • Judy Turner

      I was also 11 when I started my period and I hated it. My breasts did not develop until I was 14 and my mean brothers used to ask me “why bother” when we folded laundry and one would come across one of my bras, until I started twirling their athletic straps around on my finger and asking them whose jock strap was the super small. I weighed 86 pounds when I started my period and am northern European, Irish, Scots and Welsh. All four of my sisters started their periods by the time they were 11 or 12 and all were very slim. We are all still slim and no cancers or heart problems, but I have kidney disease like my grandmother and my mother however none of us were or are diabetic. I had chronic cysts on my ovaries and uterus when I was 40 and had them removed–been” menopaused” since then. One does not “get” a period one “starts menses.”

  • Allie from Albany

    I was 10 when I started and 57 when I stopped. At age 58 I was diagnosed with stage IIIc Ovarian cancer.

    What causes ovarian cancer? Too much ovulating! At present, there is no test for ovarian cancer, and double check this with your doctor. The test you get at the gynecologist is for cervical cancer only.

    Ovarian cancer presents very few symptoms. SEVENTY FIVE PERCENT OF PEOPLE ARE NOT DIAGNOSED TILL THEY ARE IN LATE STAGE CANCER.

    My best bit of news is for AA women: for some reason, this cancer is not as common among AA’s as it is among other ethnic groups. I myself am of German and Irish ancestry.

    • Maria

      I am so sorry to read about your diagnosis. Ovarian cancer is tough—know 2 women who faught it like heck. Best wishes and prayers for you.

    • SciGuy

      No, sorry but you are wrong.
      What causes ovarian cancer today is the extreme amount of hormone-mimicking compounds in the foods, containers, air and water. My company runs cancer clinical trials and ovulating too-much is not even a real thing: you ovulate exactly how many times you have ovum ( eggs. ) No more or less. If you start earlier then you end earlier.

  • Bethany

    This “study” is faulted.. I am of European descent,was slightly overweight as a child,started menstruating at 9 years old as did,I am told, my paternal grandmother.. I was taller than my classmates until menses began but I did not get much taller and they passed me, height-wise. My 3 sisters began menses at a normal age. They were all much slimmer than I … So,in my case, it is all in genetics and if I could fix it, I would delay the onset of menses until about the age of 18-it does take away one’s childhood.

  • Bruce

    i have a job in the medical field where I interact with people of many different races. This is just observation of course, but it does entail thousands of people over many years, where I pretty much always knew their ages. Black children appear older than other children, seem to deveop sexually at an earlier age; reaching adulthood sooner. East Asians seem to develop more slowly physically; while Whites are in the middle. East Asians seem to have healthier old ages, while Blacks tend to be obese, and die younger. I know, I know what is true on average may not be true at all for the individual; and all is confounded by mixed racial heritage. Don’t pop a cork, just some cassual observations.

    • freestar

      What is so odd to me is that people like you can work someplace for “many years” and still come up with the opinions/observation that you want to.
      When it comes to race, whites are very guilty of that.I am black and have always lived in the same black community (I’m over 40yrs). There are whites and Asians (from India and Phillipines ) who have been working in this area for MANY years. If you ask each of them the same questions about the same nieghborhood and same blacks- you will get dramatically different statements. Yet all of these whites and asians swear their opinions are based soley on what they have seen for years.
      My observation has been that your pre-existing political and racial attitudes shape what they see. Even if black girl get their periods 4 -6 months earlier (Thats it?!)- that does not spell black kids look older and are more sexual earlier somehow by nature. It has a more to do with income and class. Black girls who are solidly middle class do NOT look or act older and more sexually mature. In fact, the behavior of teen and college aged white girls in the same middle and upper classes is promiscuios by comparison.
      Does and 8 year old black kid look older than an 8 year old white? No. Does as 12 or 13 year old black kid look older than same age white? Go to any black junior high and you will see the answer is no. Do you see more young black kids acting “pushier” or louder and more aggresive than other kids do or should? Depending on where you are- yes.
      It is notable that whites often claim low income white kids “look” older, bigger, meaner, and the girls are ready for the strip club by 15 or 16 yrs. This is a bias that affects how they are treated, prosecuted, or represented when they are victims of violent and/or sexual assualt.

  • Jen

    This is nonsense. I remember my mother always saying because she got a period and breasts at 9 years-old, so would I. Nope. Instead I got it at 14 and I’ve always been pretty flat (especially in comparison to my mother). We’re European. Even in the same family there is no guarantee you’ll be similar. This sounds like another way to pick people apart and make use genetics to prove opinion.

    • Brian

      Of course there are no guarantees here– they’re talking about tendencies and averages.

  • Billy

    Why is there no mention about the study of diet? Might the growth stimulants that have been put into the food chain put a faster aging process into humans?

  • tosha

    I am AA, I was 11 and I was extremely built, they used to call me He-man when I was a kid. I had my son at age 14. In 2003, age 27, I was diagnosed with PCOS{ (Polycystic Ovararian Syndrone), it’s is when your hormones produce Androgens, too much Estrogen and not enough Progesterone}. Effects of PCOS is Diabetes type II and Heart Disease, Sterilization, Metabolic Disorders and a host of other problems. Currently, I have diabestes (type II), I havn’t hade any more children or have been pregnant and I was just told that my cholesterol is elevated. And guess what you all, I;m only 36!!!!! What the hell!!!, So check tyour self and ask your doctor are you at risk for PCOS, cause it is a silent killer and women aren’t even aware that they may have it..

    • Whiteghost1

      Thank you for your post, Tosha!

  • David

    Being the father of two beautiful bi-racial girls articles such as this tend to catch my eye. I remember reading a number of years ago an article similar in nature to this one citing that AA girls develop/menstruate earlier due to chemicals they used on their hair. Not really sure what I thought about that article but I see they are still looking for the answer!

  • Wendy Bryan

    Considering how long we now live and the mistakes that people often make while growing up, it would be beneficial if we could delay puberty until a person matures emotionally, gets educated and learns to behave like a responsible adult. The only biological purpose of puberty is sexual maturation, which do not include good sense.

    • Jim

      My daughter started hers at 9. She was always much taller than everyone else and seemed to be much more mature than most girls her age. She has played sports since she was 5. Very slim and of European descent. Her mother and I are are 5’8″ and 5’2″ respectfully. The Dr. said she was going to be 5’7″. Well 4 years later, she hasn’t grown in a year, everyone on her team has caught up to her.
      I think it’s a crap shoot.
      I kid her mother and her that it was the STEROIDS in the chicken nuggets she used to devour as a child ! Since she stopped eating them it has stunted her growth!
      P.S. I then make sure to tell her that no matter what, she the most beautiful child in the world.

  • ginny

    Gad, another health issue about being an African American or a descendant from Africa. Seems we are doomed from the start!

    • ScottH

      Ginny, A increased genetic risk does not mean that someone will get a certain condition. There are a lot of factors involved beyond genetics that play a role in disease, but knowing of a risk can help in taking actions that may help prevent a disease from developing.

  • Meechel

    I was 8 when I got boobs and 9 when I got my “curse” as my family called it. I was not fat, very skinny and small for my age. I am white as all get out, though I am 40 and overweight.

  • Mellissa Jones

    One of the theories as to the reason for breast cancer has to do with the wearing of bras. When a girl is pubescent earlier then western and westernized societies demand that she wear a bra. This restricts the fluid flow in the lymphatic system from the breasts which can leave toxins in the breast tissue causing breast cancer. According to studies women from non-westernized cultures have a dramatically reduced incidence of breast cancer however when bra use is introduced the incidence of breast cancer increases to the nominal rate of westernized countries. http://www.brafree.org/links.html
    There are ways of preserving one’s “modesty” without restrictive bras.

  • Quwande

    I hate these types of articles, they always present negative opinionated bs, especially concerning African Americans. African Americans stem from over 60 different tribes and most are substantially genetically different from one another. They use these small studies that are overly generalized, then come up with these bs theories, then give us bs preventative medicine that likely does more harm than good. I don’t care about your statistics, I want you out of my business, and for you to stop making stereotypes out of us—using you bias scientific methods. We know what your about, and that’s labeling. We know about your experiments you so love to run i.e Tuskegee. I don’t trust you and no one should. Do study on your own people. You make me sick.

    • John Mingy

      Just because something is specific to one ethnic group doesn’t make it a stereotype. As someone with European roots, should I feel stereotyped because this study claims that some percentage of European girls reach puberty later than some percentage African American girls?

      Perhaps instead of becoming emotional you should attempt to find/conduct better research that counters what has already been done, or else find specific points about the existing research that casts doubt on its validity.

  • Jason Bligh

    This article is TOTALLY racist. To say that a particular race is any different in any way from any other race is outright wrong. Next it will be all right to say that some races are less intelligent than others or that they are more prone to commit violent crimes with edged weapons. This does not fit with todays social agenda in which everybody is equal in every way.

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