Is obesity leveling off and what does it matter?

January 23rd, 2010 by MorganDowney Leave a reply »

Ten days ago, the media was touting new reports from the CDC that the obesity epidemic was ‘leveling off’ or  ‘reaching a plateau.’ The news was taken in some quarters with a sense of relief:”Whew, I’m glad that’s over.” Well, don’t get too comfortable. The reports have a lot more to say and overall, this is not a time for complacency.

What the reports actually say.

First, regarding adults, (Prevalence and trends in obesity among US adults, … [JAMA. 2010] – PubMed result), the authors note that the prevalence of obesity is high, exceeding 30% in most age and sex groups except for men 20-39 years old. Strong racial and ethnic differences persist with very high rates among African-American and Hispanic Americans compared to white Americans. Prevalence of severe or morbid obesity, called class 3, (a BMI of 40 or more) was 5.7% overall, with 4.2% for mean and 7.2% for women, including a rate of 14.2% among non-Hispanic black women. What their analyses found was that the earlier rates of increase were on the order of 6 to 7 percentage points. In the this analysis, over the past ten years, the rate of increase is 4.7 percent. Bottom line: rates are still going up.

Second, regarding children, (Prevalence of high body mass index in US children … [JAMA. 2010] – PubMed result) the authors found no statistically significant increases over the last 10 years among girls. Among boys, there is a different picture. Heavy boys between 6 and 19 years of age are getting heavier. Bottom line: the prevalence of obesity has tripled among school-age children and adolescents if you go back to the 1980s. It is high – 17%- and remains high.

So, is the epidemic leveling off? Answer: we don’t know yet. These analyses look at the last ten year trends and they are less than the peak periods of increase. Is this a pause on an upward track or the start of a decline?

Experts I talked with are not too optimistic. First, there is the perennial question of relying on the BMI. A recent paper indicates that more precise tools, like skinfold tests, would have predicted the obesity epidemic by 10-20 years. The timing of the rise in U.S. obesity varies with… [Econ Hum Biol. 2009] – PubMed result. Second, there isn’t a clear explanation of why the rates should be leveling off. We’d like to think people are changing their behavior but the evidence is there is less compliance with recommended dietary and physical activity standards than ever. Adherence to healthy lifestyle habits in US adults… [Am J Med. 2009] – PubMed result  Compliance with the DASH diet among persons with hypertension has slipped. Deteriorating dietary habits among adults with hyp… [Arch Intern Med. 2008] – PubMed result

The recession may be causing people to forgo buying more expensive but healthier foods Recession Weighs on Waistlines – Many clinicians running medical weight management programs I have talked with report their volume is down 20-30%.

Hopefully, this is the beginning of a levelling or downard trend in obesity but we will not know for sure until more information comes in. In the meantime, we should consider that we don’t to be having phenomenal increases in obesity to justify more programs for treatment and prevention. An editorial  by J Michael Graziano on the two reports from CDC, states, “Even if these trends can be maintained, 68% of US adults are overweight or obese, and almost 32% of school-aged US children and adolescents are at or above the 85th percentile of BMI for age. Given the risk of obesity-related major health problems, a massive public health campaign to raise awareness about the effects of overweight and obese is necessary..Major research initiatives are needed to identify better management and treatment options. The longer the delay is taking aggressive action, the higher the likelihood that the significant progress achieved in decreasing chronic disease rates during the last 40 years will be negated, possibly even with a decrease in life expectancy.”  Amen.