Poorer teens more apt to be fat

Several decades of medical studies show gap widening


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 could be tied to inactivity, soft drinks and even skipped breakfasts, scientists said yesterday.

The findings, drawn from national health surveys dating to the early 1970s, add a dimension to the issue of 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 the poor.

"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 A. Miech, a sociologist at the Johns Hopkins Bloomberg School of Public Health who directed the study.

Miech said the poor 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 and little or no nutrition. On the positive side, he said, teenagers of all income groups should benefit from a recent pledge by beverage companies to stop selling soft drinks in the nation's schools.

The obesity-income link, documented in a study appearing in today's Journal of the American Medical Association, first showed up in the late 1980s. The gap 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 K. 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 choices about what to eat, have more of their own money to spend and might watch more television. Other studies have also shown that fast-food and soft-drink companies have successfully marketed their products to minority teens, she said.

Compounding the problem, she said, is the fact that supermarkets offering healthy foods are generally located in wealthier neighborhoods, leaving the poor to rely on convenience stores stocked with processed foods.

Meanwhile, organized sports leagues are less prevalent in poor neighborhoods, which also have fewer safe parks. As a result, teens don't have the chance to burn off the calories consumed through diets laden with sugar and fat.

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 more recent period, 23 percent of poor children 15 to17 years old were overweight, compared with 14 percent of wealthier teens. Similar differences were found among both girls and boys of different income groups.

The gap narrowed among African-American teens, with 25 percent of poor youths turning out to be overweight, compared with 22 percent of well-to-do teens.

Researchers were not sure why this was so, though they speculated that dietary patterns among black youths might cross income lines more than among other groups.

The researchers used the federal definition of poverty - a sliding scale that would apply to a family of four with an income no greater than $20,000 in 2006. To qualify as overweight, a teenager must a body mass index - a height-to-weight ratio - that places him or her in the 95th percentile or above.

For example, a 16-year-old boy who stands 5-feet-5 would have to weigh at least 166 pounds to qualify as overweight. A 16-year-old girl who stands 5-feet-3 would weigh at least 163 pounds.

The surveys highlighted dietary and exercise habits that could contribute to obesity.

Among high school students, for instance, the percentage of dietary calories coming from sweetened beverages increased 20 percent overall during the past decade. But it increased 67 percent among the poor, compared with 14 percent among higher-income groups.

The poor were also more likely to be inactive and to skip breakfast, despite the availability of school programs providing free and reduced-price meals. Teens who skip breakfast might overcompensate later in the day by gorging on junk food, Miech said.

The findings resonated among pediatricians, who said they are seeing health consequences rarely found in the past among patients so young. "I've never before seen as many of these mid-teenagers getting high blood pressure," said Dr. Steven Caplan, a pediatrician at Sinai Hospital. He said he also is seeing poor children - particularly African-Americans - developing the early warning signs of type-2 diabetes.

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