NIH Disses Physical Activity as Cure of Childhood Obesity

November 23rd, 2011 by MorganDowney Leave a reply »

The National Heart, Lung and Blood Institute has issued guidelines endorsed by the American Academy of Pediatrics. They are directed to all primary pediatric care providers to address the known risk factors of cardiovascular disease, including obesity, blood pressure, cholesterol, tobacco and lipids.

The report notes that longitudinal data on non-white populations are lacking and that “Clinically important differences in prevalence of risk factors exist according to race and gender, particularly with regard to tobacco-use rates, obesity prevalence, hypertension, and dyslipidemia.”

The report notes, “Obesity tracks more strongly than any other risk factor, among many reports from studies that have demonstrated this fact…Tracking data on physical data is more limited.”

Regarding overweight and obesity, the report states,

“The dramatic increases in childhood overweight and obesity in the United States since 1980 are an important public health focus. Despite efforts over the last decade to prevent and control obesity, recent reports from the National Health and Nutrition Examination Survey show sustained high prevalence: 17% of children and adolescents have a BMI at the >95th percentile for age and gender. The presence of obesity in childhood in childhood and adolescence is associated with increased evidence of atherosclerosis at autopsy and of subclinical measures of atherosclerosis on vascular imaging. Because of its strong association with many of the other established risk factors for cardiovascular disease, obesity is even more powerfully correlated with atherosclerosis; this association has been shown for BP, dyslipidemia, and insulin resistance in each of the major pediatric epidemiologic studies. Of all of the risk factors, obesity tracks most strongly from childhood into adult life.”

Given that physical activity is a primary prescription for preventing childhood and adolescent obesity, it is interesting to read what the expert panel has to say about its utility:

“A moderate number of RCTs (randomized controlled clinical trials) have evaluated the effect of interventions that addressed only physical activity and/or sedentary behavior on prevention of overweight and obesity. In a small number of these studies, the intervention was effective. It should be noted that these successful interventions often addressed reduction in sedentary behavior rather than attempts to increase physical activity. In a majority of these studies there was no significant difference in body-size measures. Sample sizes were often small and follow-up was often short (frequently < 6 months). ..Overall, the expert panel concluded that on the basis of the evidence review, increasing activity in isolation is of little benefit in preventing obesity. By contrast, the review suggests that reducing sedentary behavior might be beneficial in preventing the development of obesity.”

The report identifies populations at special risk for obesity: children with a BMI between the 85 and 95th percentiles;children in whom there is a positive family history of obesity in 1 or both parents; early onset of increasing weight; excessive weight gain during adolescence; children who have been very active and become inactive. See Integrated Guidelines for Cardiovascular Health and Risk Reduction in Children and Adolescents- NHLBI, NIH