The National Heart Institute has followed more than 15,000 residents of Framingham, Massachusetts and their descendants, giving them comprehensive physicals every four years. This data has resulted in a treasure trove for medical research. Recently two social scientists, Nicholas Christakis and James Fowler, began using this data to study behaviors of the participants. They discovered that good behaviors — like quitting smoking or staying slender or being happy — pass from friend to friend almost as if they were contagious viruses. The Framingham participants, the data suggested, influenced one another’s health just by socializing. And the same was true of bad behaviors — clusters of friends appeared to “infect” each other with obesity, unhappiness and smoking. Staying healthy isn’t just a matter of your genes and your diet, it seems. Good health is also a product, in part, of your sheer proximity to other healthy people. By keeping in close, regular contact with other healthy friends for decades, Eileen and Joseph had quite possibly kept themselves alive and thriving.
When a Framingham resident became obese, his or her friends were 57 percent more likely to become obese, too. Even more astonishing to Christakis and Fowler was the fact that the effect didn’t stop there. In fact, it appeared to skip links. A Framingham resident was roughly 20 percent more likely to become obese if the friend of a friend became obese — even if the connecting friend didn’t put on a single pound. Indeed, a person’s risk of obesity went up about 10 percent even if a friend of a friend of a friend gained weight.
“People are […]