The September 10th edition of the New York Times magazine featured an in-depth article on social contagion effects in health and happiness. The article examined evidence from several studies – including Add Health – regarding the theory that health behaviors can pass from friend to friend like contagious “viruses.”
At the heart of the discussion is recent research conducted by Nicholas Christakis and James Fowler. The pair analyzed social connections between participants in the Framingham Heart Study and found that several behaviors and conditions – including smoking, drinking, obesity, and happiness – appeared to spread from person to person. For example, “When a Framingham resident became obese, his or her friends were 57 percent more likely to become obese, too. Even more astonishing…was the fact that the effect did not stop there. In fact, it appeared to skip links.”
When Christakis and Fowler repeated their analyses using Add Health data, they found the same three-degree pattern of contagion for obesity. However, research by other Add Health investigators has called into question whether confounding effects such as homophily – the tendency of people to gravitate toward others who are like them – or shared environment are at play.
Regardless of how one judges the evidence, Christakis and Fowler’s work may suggest “a new way to think about public health. If they’re right, public-health initiatives that merely address the affected individuals are doomed to failure.” (September 10, 2009. Are Your Friends Making You Fat? In New York Times magazine.)
To read the entire New York Times magazine article, click here
This article is based on research published as the following:
Christakis, Nicholas A. and James H. Fowler. 2007. The spread of obesity in a large social network over 32 years. New England Journal of Medicine 26, 357(4): 370-9.
Cohen-Cole, and Jason M. Fletcher. 2008. Detecting implausible social network effects in acne, height, and headaches: longitudinal analysis. BMJ 337:a2533.
Fowler, James H. and Nicholas A. Christakis. 2008. Estimating peer effects on health in social networks: a response to Cohen-Cole and Fletcher; and Trogdon, Nonnemaker, and Pais. Journal of Health Economics 27(5): 1400-5.
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