Two researchers who studied Army families say that those assigned to communities with higher rates of obesity were more likely to be overweight or obese than those assigned to bases where obesity was less common. “That finding, published this week in the journal JAMA Pediatrics, offers the first quasi-experimental evidence to support the theory that obesity spreads through social contagion,” says the Los Angeles Times.
The research follows work done by Nicholas Christakis of Yale and James Fowler of UC-San Diego, who found that various kinds of behavior seem to spread through social networks — “as if they were contagious,” says the Los Angeles newspaper. In a 2007 study, Christakis and Fowler “reported that if a person’s friend, sibling, or spouse became obese in a certain period of time, the chances that he or she would become obese as well increased by 37 percent to 57 percent.”
In the study of Army families, economists Ashlesha Datar of USC and Nancy Nicosia of the Rand Corp. analyzed data about teens and their parents. “After adjusting for factors like age, sex, education, income, and military rank, the researchers found that members of military families were more likely to be overweight or obese if they had been deployed to a county where obesity was more of a norm,” says the Times. They also found that families who lived off base were more likely to have a high body mass index than those who lived on base. The study has limitations: Proximity doesn’t mean people share social networks, military families may not reflect the U.S. population, and the height and weight data used in the research was self-reported.