The study, published in the Proceedings of the National Academy of Sciences, builds on two decades of previous research that points to causal associations between social relationships and mortality. It is the first to link social relationships with measurable aspects of physical well-being. Inflammation, high blood pressure, and abdominal obesity were all taken into consideration. These issues could lead to long-term health problems, such as heart disease and cancer. The researchers looked at when the effects on health took place and how long those effects lasted.
Sociologist Kathleen Mullan Harris and a team of UNC-Chapel Hill researchers drew on data from four nationally representative surveys of the U.S. population. Altogether, the surveys covered over 14,000 participants at different life stages from adolescence to old age. The researchers looked at the number of friends each person had, their community involvement, whether they were married, and whether they were religiously affiliated. They looked at the quality of each person's relationships. Did the person find their relationships to be critical and supportive? Or, did they find their friends and relatives to be troublesome and argumentative?
The team then looked at how each participant's social relationships related to the four key mortality risk markers: blood pressure, abdominal fat, BMI, and inflammation.
The researchers found that the size of a person's social network is most important for a person's health when they are in their teens and old age. Social isolation causes teens to have an increased risk of inflammation by the same amount as teens who don't exercise. Social integration as a teen also protects against abdominal obesity. Social isolation in old age is more harmful to developing and controlling hypertension than diabetes.
For participants in their mid-30s to 50s, the number of social connections didn't matter. What mattered was the quality of those connections and whether they provided social support or strain. Harris guesses that quality matters more than quantity for this age group because they are maintaining relationships with their children and parents. Thus, they have a large social network by default.
The medical field should encourage teens and young adults “to build broad social relationships and [develop] social skills for interacting with others,” Harris said. Strong social bonds are critical for our physical well-being throughout the course of our lives.
So force yourself to get involved in social activities. Invite your friends over. Hang out with people who make you feel good and cut ties with those who make your life harder. It’s good for you.
Sources: EurekAlert! press releases via University of North Carolina at Chapel Hill, "Social relationships and physiological determinants of longevity across the human life span” via PNAS