Poverty an indicator of obesity in teens

Teenagers who live in poverty are 50 percent more likely to be overweight than those from wealthier families, a gap that has appeared in the past two decades and may be tied to inactivity, soft drinks and skipped breakfasts, scientists said Tuesday.

The findings, culled from national health surveys dating to the 1970s, add a new dimension to the growing focus on obesity among American youth. While study after study has documented a doubling of teen obesity rates over the past 30 years, the new research shows that the problem is more concentrated among low-income families.

"If you're poor, you are more likely to live in a neighborhood that is perceived as dangerous — you're less likely to go out after dusk, take a walk or do something that requires physical exertion," said Richard Miech, a sociologist at the Johns Hopkins Bloomberg School of Public Health who directed the study.

Miech said poor people are also more apt to live on diets of junk food, key features of which are soda and sweetened fruit drinks that pack lots of calories but little or no nutrition.

The obesity-income gap, documented in a study appearing in today's Journal of the American Medical Association, first showed up in the late 1980s and has been widening ever since.

What's more, the study shows that poor children have about the same obesity rate as wealthier children through age 14. Then, a transformation occurs — and obesity rates rise much faster among children from low-income homes.

"It shines a light on a particular period when kids are becoming more autonomous in making more of their own decisions," said Shiriki Kumanyika, a co-author who is a professor of epidemiology at the University of Pennsylvania School of Medicine.

Youngsters in this age group increasingly make their own decisions about what to eat, have more of their own money to spend and may watch more television. Other studies also have shown that fast-food and soft-drink companies have successfully marketed their products to minority teens, she said.

Compounding the problem, Kumanyika said, is the fact that supermarkets offering healthful foods are generally located in wealthier neighborhoods, leaving low-income families to rely on convenience stores stocked with processed foods. Organized sports leagues are less prevalent in poor neighborhoods, which also have fewer safe parks.

The researchers compared data from four national health surveys conducted by the U.S. Centers for Disease Control and Prevention. The first covered the period 1971 through 1974, and the last, 1999 through 2004.

In the most recent period, 23 percent of poor children 15-17 were overweight, compared to 14 percent of wealthier teens. Similar differences were found among both girls and boys of different income groups.