BMI bludgeon bad


By John DiTraglia - Contributing Columnist



Two simultaneous reports in JAMA Pediatrics and a rash of commentary puts the lie to the well meaning effort to use the body mass index (BMI) of children to treat or prevent obesity.

This idea stems from three seemingly logical precepts. The first being that an ounce of prevention is worth a pound of cure. Since obesity is well nigh intractable once established, what we should be doing is preventing it. This seems to be manifestly wrong in the case of obesity. Another established observation is that for a certain subset of fat kids and their parents, they seem to be either not paying attention or not caring enough or just willfully blind to the fact of obesity and we need to do the special sauce of measuring and calculating and feeding back the BMI of kids to break through this. The third thing that has led us down this blind alley is the belief that if those kids and their parents would just find out about their predicament they would mend their ways and fix it.

In the first original investigation, using data from 79 California schools (28,641 students participating up to 3 years), BMI reports sent to parents had no effect on weight and shape at 1 year or 2 years of follow-up. But they did find several adverse outcomes.

They introduce the report with the usual observation that obesity is rampant but also that in order to try and fight this epidemic, “As of 2013, a total of 25 states required schools to screen students’ body mass index (BMI), and 11 states required that schools report BMI results to parents in an effort to reduce pediatric obesity.” The adverse effects of this project were assessed by multiple surveys of attitudes and eating and dieting behaviors. They found an important increase in external and internalized stigmatization of obesity. So two things: first – stigmatization did increase that you might say is really the object of this BMI measuring and feeding back to kids and their parents and second – it doesn’t work. They conclude that, “To improve student health, schools should consider investing resources in evidence-based interventions.” But they don’t mention any such evidence-based interventions.

The second original investigation conducted in the United Kingdom, used data from a total of 22,503 adolescents in 3 UK cohorts spanning 30 years and found that the prevalence of behaviors aimed at achieving weight loss increased in 2015 compared with both 2005 and 1986 and that this change was not explained by known changes in body mass index alone. Weight-control behaviors increased more in boys than in girls, but among the latter, these behaviors were associated with greater depressive symptoms in 2015 compared with 2005 and 1986. These authors suggest that an increased societal and public health focus on obesity could have had unintended consequences related to weight-control behaviors and poor mental health; thus, they go on to recommend that public health campaigns around the prevention of obesity should include prevention of disordered eating behaviors and be sensitive to adverse outcomes such as poor mental health. During the same period in the UK, as in the US, the proportion of adolescents with an overweight or obese body mass index (BMI) almost tripled.

I have listed some commentary in the references but in my final analysis, as I have already tiresomely written in the past, the BMI bandwagon, that has also taken firm hold of medical practitioners, looks like we’re trying to do something for God’s sake but it is worse than helpful.

Madsen KA, et al.Effect of School-Based Body Mass Index Reporting in California Public Schools. A Randomized Clinical Trial. JAMA Pediatr. Published online November 16, 2020. doi:10.1001/jamapediatrics.2020.4768

Francesca Solmi F et al. Changes in the Prevalence and Correlates of Weight-Control Behaviors and Weight Perception in Adolescents in the UK, 1986-2015

JAMA Pediatr. Published online November 16, 2020. doi:10.1001/jamapediatrics.2020.4746

Tracy K. Richmond, MD, MPH1,2; Idia B. Thurston, PhD3; Kendrin R. Sonneville, ScD, RD4. Weight-Focused Public Health Interventions—No Benefit, Some Harm. JAMA Pediatr. Published online November 16, 2020. doi:10.1001/jamapediatrics.2020.4777

Childhood Obesity Campaigns: All Harm, No Benefit

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By John DiTraglia

Contributing Columnist

This writer’s opinion is their own and not the opinion of this newspaper

John DiTraglia M.D. is a Pediatrician in Portsmouth. He can be reached by e-mail- jditrag@zoomnet.net or phone-354-6605.

This writer’s opinion is their own and not the opinion of this newspaper

John DiTraglia M.D. is a Pediatrician in Portsmouth. He can be reached by e-mail- jditrag@zoomnet.net or phone-354-6605.