Over the past two decades, more and more research has pointed to quality social relationships as being a major determinant of both physical and mental health over time. In an oft-cited study, the experience of chronic loneliness carried even more of a mortality risk than smoking 15 cigarettes per day.
The exact mechanisms for this have been a bit less clear. And first and foremost is the problem of correlation versus causation: Since most studies of the impact of social connections on health are observational, they can’t definitively prove what causes what. It’s not hard to imagine that those who are already prone to health problems might, in turn, have poorer social relationships as a result of those health problems. Additionally, there could be entirely new variables at play that influence both: Substance abuse, for instance, is known to take a toll on both social relationships and physical health.
Nonetheless, it remains quite likely that social relationships actually help protect and improve physical health. And one possible mechanism that is gaining traction is the idea of inflammatory markers. New research published this month in Brain, Behavior, and Immunity creates an even stronger link between social relationships and potential effects on biological markers like inflammation and, in fact, the aging process itself.
In this most recent study, characteristics of more than 2,000 middle-aged adults in the United States were observed. Their data was part of the Midlife in the United States (MIDUS) data set, which measures—in addition to many other characteristics—a construct called cumulative social advantage (CSA). CSA is an aggregate assessment of one’s level of social connection across four domains: religious and faith-based support, parent-child relationship quality, community engagement, and extended emotional support.
In this study, CSA was measured against blood samples, including a widely used index of biological age called GrimAge. It turns out, there was a significant correlation between CSA and biological aging: The higher the social advantage, the slower the aging, and the lower the inflammation.
Of course, this is still at its heart a correlational study. There could be the same discrepancies in causal direction that any observational research is prone to. And though the statistical technique of structural equation modeling that was used in this study can begin to suggest potential causal effects, it cannot prove them.
Nonetheless, isolating specific long-term biological factors that differ between those with high social connectedness and satisfaction versus those with low, lessens the possibility that other confounds of lifestyle behaviors are accounting for the differences. It suggests that there are subtle and long-lasting physiological changes—even at the cellular level—in people who have strong social ties, and it is not unlikely that strong social ties are at least one cause of those characteristics. Perhaps strong social ties bring in additional effects like lower blood pressure, a more functional immune system, and more exposure to novel stimuli, all of which are good for the body and brain.
This all points to yet another reason to prioritize friendships as much as you would prioritize exercise, nutrition, or any other more “traditional” tool for increased physical health.
