Humans are social animals. We thrive through contact with other people, and the importance of that connection can be seen by what happens in its absence.
Several studies have shown the damaging impact loneliness has on human health. The adverse health effects of loneliness rival that of smoking and obesity, according to recent studies done by scientists at UC San Diego.
Loneliness, A Growing Problem
Growing isolation and loneliness, particularly among the elderly, have prompted public health responses. Two years ago, the United Kingdom created the first national strategy to deal with the health consequences of isolation. In the United States, the National Academies of Sciences has begun to study the problem.
But beyond trying to combat social isolation, scientists are also researching for possible genetic predispositions toward loneliness. They are also looking at where those associations might overlap with risks for specific health outcomes.
Genetics Also Plays a Role
Two recently completed studies offer compelling evidence of a genetic predisposition toward loneliness. Both studies, which included data from 23andMe and the UK Biobank, found shared genetic associations between loneliness and other conditions like cardiovascular disease, as well as psychiatric and metabolic disorders.
One study, led by researchers at the University of California at San Diego, found a clear association between loneliness and coronary artery disease, particularly among women. The study, published in the journal Human Molecular Genetics used data from more than half a million individuals. The researchers found 19 variants associated with a predisposition toward loneliness. Those variants were also associated with cardiovascular disease, as well as some psychiatric and metabolic disorders. Associations between major depressive disorder, loneliness, and heart disease have been described in previous studies. But this study found that the associations are partly explained by genetics.
Another study, from researchers at Vanderbilt University Medical Center, used electronic medical records as well as data from 23andMe, the UK Biobank, and others. That study looked at the connections between loneliness, major depressive disorder, and coronary artery disease. That study found that individuals with genetic risk for loneliness and major depressive disorder were more likely to have clinical diagnoses for coronary artery disease. This association was stronger in women than in men, and the effect was specific to loneliness.
The studies come amid increased attention to the genuine public health consequences of loneliness, particularly among older people. The researchers suggest that understanding conditions associated with loneliness could help in developing ways to address the issue.