Obesity Rates: A Glimmer of Hope?

Henry R. Black, MD


May 30, 2014

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Hi. I am Dr. Henry Black, Adjunct Professor of Medicine at the New York University Langone School of Medicine and former president of the American Society of Hypertension.

A major public health issue that we are seeing these days (and we can't miss it) is obesity. This problem is relatively new, if we look at the spectrum of problems and risk factors for heart disease. We didn't notice the increased rate of obesity until about the middle of the 1990s. In 2003, for example, more than one third of adults and about 17% of children were considered obese or overweight.[1] Of course, children who become overweight during childhood and adolescence tend to become obese later.

The National Health and Nutrition Examination Survey (NHANES), which began earlier in the 20th century, has been following the US population in a predetermined group for decades. One of the most interesting findings of the 2011-2012[2] data is that obesity rates seem to be stabilizing, especially in younger children.

NHANES uses the usual definitions of obesity in that a body mass index (BMI) of 25-29.9 kg/m2 is considered overweight. Below 25 kg/m2 is considered normal weight. More than 30 kg/m2 is considered obese.

They also graded obesity according to BMI. Grade I was 30-34.9 kg/m2; grade II was 35-39.9 g/m2; and grade III, the highest grade, was more than 40 kg/m2.

They looked at all children: infants, children from age 2-5 years, older children, and adolescents. The finding that has interested people is not that the overall obesity rate seems to be stabilizing, but that for children 2-5 years of age (in whom obesity was defined as weight in the 95th percentile compared with height, using characteristic standards), the rate of obesity was decreasing. For the first time since this has been followed, there was a reduction in obesity.

For older adults, obesity rates were the same -- about one-third were overweight, and Hispanic and non-Hispanic black persons had the highest rates of obesity. This is well known and has been true in the past.

They looked at a sample of Asian Americans for the first time systematically, and rates of obesity in Asian Americans were the lowest of any of the groups they looked at. But there has been some concern that just looking at BMI in Asian Americans is not an adequate way to judge the risks associated with obesity. Most Asian countries, in fact, have different cut-off points for obesity.

What does this mean, and why is it happening? Is it just a chance finding? Perhaps. Or is the public health campaign about obesity finally getting through? That would be very nice.

This has been a major issue politically as well as in nutrition societies, because we know that if you are overweight as a child, you tend to be overweight as an adult. The best time to intervene is in younger children.

I hope that this is not just a chance finding, because the impact of obesity on hypertension, diabetes, cardiovascular risk factors, falls, and osteoarthritis is dramatic and important. We need to turn it around.

One thing that we have to remember, however, is that we need to be patient. It took 25 years from the unequivocal identification of smoking as having an impact on cardiovascular disease and lung cancer before we started to see smoking rates turn around. So personally, I am very encouraged.

We will follow this very closely. Pediatricians have to be particularly vigilant to advise parents of children that they can do something about this. It may just be the sugar in soft drinks, but it may be something else. We have to pay attention. Thank you very much.


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