Thursday, July 26, 2007
Obesity can spread from one person to another like the flu or a fad, researchers report today in a first-of-its-kind study that helps explain - and could help fight - one of the nation's biggest public health problems.
And how did they reach this conclusion?
The researchers found that when one spouse became obese, the other was 37 percent more likely to do so in the next two to four years, compared to other couples. If a man became obese, his brother's risk rose by 40 percent.
The risk rose even more sharply among friends - between 57 and 171 percent, depending on whether they considered each other mutual friends. Moreover, friends affected friends' risk even when they lived far apart, the researchers found.
And why did they reach this conclusion?
"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 published today in the New England Journal of Medicine. "And the answer is, 'Yes, it does.' We are finding evidence for a kind of social contagion."
Watch out. They'll be quarantining fat people next. Or banning them from friendships:
"What spreads is an idea. As people around you gain weight, your attitudes about what constitutes an acceptable body size changes, and you might follow suit and emulate that body size," Christakis said.
Adds the New York Times:
It may also mean that the way to avoid becoming fat is to avoid having fat friends.
That is not the message they mean to convey, say the study investigators, Dr. Christakis and his colleague, James H. Fowler, an associate professor of political science at the University of California, San Diego.
You do not want to lose a friend who becomes obese, Dr. Christakis said. Friends are good for your overall health, he explained. So why not make friends with a thin person, he suggested, and let the thin person’s behavior influence you and your obese friend?
Speaking of spreading ideas, expect the idea that fat people are pariahs to spread, too:
Other researchers used words like "brilliant" and "groundbreaking" to describe the work and said it is likely to lead to a flurry of new research.
"This is one of the most exciting studies in medical sociology that I've seen in decades," said Richard Suzman, director of the behavioral and social research program at the National Institute on Aging, which funded the study. "I think these results are going to shift the way we think about some of these supposedly non-communicable diseases."
Here's the study, though you have to wade through language that's a little off-putting - such as "ego" and "alter" instead of "subject" and "friend or relation":
Whereas increasing social distance appeared to decrease the effect of an alter on an ego, increasing geographic distance did not. The obesity of the most geographically distant alters correlated as strongly with an ego's obesity as did the obesity of the geographically closest alters. These results suggest that social distance plays a stronger role than geographic distance in the spread of behaviors or norms associated with obesity.
In other words, if you aren't really friends with them you won't get fat.
And it does have some neat graphics, like this illustration of fat people and their friends and relations:
What this study really shows is that people are most comfortable being friends with those who are most like them, and who enjoy doing the same kinds of things they do. If you like to spend your spare time hiking and jogging, so will your friends. If you like to spend your time sitting and reading and going out to eat, so will your friends. If you like to spend your spare time sitting in a bar drinking, then so will your friends.
Coming next: The contagion of alcohol, tobacco, and illicit drugs. Oh, wait, we're already there.
Goodbye, free will.
posted by Sydney on 7/26/2007 08:40:00 AM 1 comments
Well, there is an adenovirus that fulfills Koch's postulates for infectious obesity in several animal models, and in humans seropositivity for antibodies to that virus is substantially correlated with obesity. There are also other infectious diseases known to influence the motivational centers of mammalian brains.
By 3:51 PM, at