(2009-09-15) Social Obesity

Obesity may have a Social (Sociogenic) component. A study published in the August issue of the American Journal of Clinical Nutrition finds that how much tweens and teens eat can be influenced by how much their friends weigh... Lead researcher and clinical psychologist Sarah Jeanne Salvy says her research demonstrates an eye-opening social theory: obesity can be contagious.

Here's a story from 2007 on the same topic. "It's almost a cliche to speak of the obesity epidemic as being an Epidemic. But we wanted to see if it really did spread from person to person like a fashion or a germ," said Nicholas Christakis of Harvard Medical School, who led the study, being published tomorrow in the New England Journal of Medicine (NEJM). "And the answer is, 'Yes, it does.' We are finding evidence for a kind of social contagion."

Apr'2010: pair of articles noting the OutBreak (heh) of Social Contagion studies. Social Network Analysis undoubtedly will play a key role in deciphering how social relationships affect health. But as the field develops, there is a danger that health professionals may fall too hard for this attractive new web of causation, while giving short shrift to key environmental factors that undeniably shape health.

Jun'2011 update: Andrew Gelman looks at some criticisms of the statistics.

See also critique by Cosma Shalizi and Duncan Watts: social contagion cannot be differentiated from other explanations, such as shared environment or homophily -- people’s tendency to seek out friends like themselves.

2012 response: "Social Contagion Theory: Examining Dynamic Social Networks and Human Behavior"