NCHR Comment on USPSTF Draft Research Plan on Weight Loss Intervention

June 14, 2023

The National Center for Health Research (NCHR) appreciates the opportunity to provide public comments on the U.S. Preventive Services Task Force (USPSTF) Draft Research Plan on Weight Loss to Prevent Obesity-related Morbidity and Mortality in Adults.

The National Center for Health Research (NCHR) is a nonprofit think tank that conducts, analyzes, and scrutinizes research on a range of health issues, with a particular focus on which prevention strategies and treatments are most effective for which patients and consumers. We do not accept funding from companies that make products that are the subject of our work, so we have no conflicts of interest.

NCHR appreciates the task force’s efforts to address weight loss interventions in adults. Obesity affects nearly half of US adults (42%) and is extremely costly to the US healthcare system, costing $173 billion in 2019.^[1] Obesity is preventable and changeable except in rare conditions. Therefore, it is essential that both behavioral and pharmacotherapy weight loss methods be rigorously evaluated to analyze their impact on morbidity and mortality in adults. Evidence points towards weight loss being helpful in most patients, but there are gaps surrounding the risks associated with varying interventions. For example, weight loss pharmaceuticals have been helpful in lowering weight, but there are some questions about whether they reduce obesity-related health problems such as cardiovascular disease and high blood pressure.^[2] This research plan will uncover important gaps around pharmaceutical and behavioral interventions in adults, as well as the risks associated with those interventions.

We have several recommendations to improve this draft research plan:

It is not clear which obesity-related measures the Task Force will consider for the Evidence Review, other than BMI and waist circumference. Research has shown that there are serious flaws with BMI that are widely recognized in social sciences.^[3] BMI does not distinguish between excess fat, muscle, or bone mass, and it does not provide any indication of the distribution of fat among individuals. We understand that many studies use BMI despite these flaws, because it is easy to calculate. What other adiposity measures will be considered, such as total body fat, fat free mass, and relative fat mass, all of which have been shown to be superior to BMI?^3,[4],[5]

We appreciate the proposed approach to address health equity across populations in this draft research plan. It is essential that benefits and harms of interventions are evaluated for specific populations, since they may vary considerably. In addition to the groups specified, we recommend the inclusion of people with disabilities. Relatively few studies have examined the effectiveness of weight loss interventions for adults with various disabilities, including intellectual disabilities. However, evidence has supported interventions that take into account the context of the lives of adults with intellectual disabilities, such as increased involvement by a caregiver in interventions.^[6]

We also recommend the inclusion of additional criteria in the Key Question 1: Health Outcomes. These additional criteria could include anxiety and mood disorders, which have been associated with obesity.^[7] People with mental health problems are 2-3 times more likely to be obese, and people with obesity have between a 30-70% increased risk of developing a mental health disorder.^[8] It would be valuable for this research plan to investigate the relationship between weight loss and improvement on significantly associated mental health disorders.

[1] Centers for Disease Control and Prevention. (2022). Adult obesity facts. Centers for Disease Control and Prevention. https://www.cdc.gov/obesity/data/adult.html

[2] Cohen, J.B., Gadde, K.M. (2019). Weight Loss Medications in the Treatment of Obesity and Hypertension. Curr Hypertens Rep 21, 16. https://doi.org/10.1007/s11906-019-0915-1

[3] Burkhauser, R. V., & Cawley, J. (2008). Beyond BMI: the value of more accurate measures of fatness and obesity in social science research. Journal of health economics, 27(2), 519–529. https://doi.org/10.1016/j.jhealeco.2007.05.005

[4] Rothman, K. BMI-related errors in the measurement of obesity. Int J Obes 32 (Suppl 3), S56–S59 (2008). https://doi.org/10.1038/ijo.2008.87

[5] Green D, et al. Is Body Mass Index Really the Best Measure of Obesity in Individuals?. J Am Coll Cardiol. 2009 Feb, 53 (6) 526. https://doi.org/10.1016/j.jacc.2008.08.078

[6] Hamilton, S., Hankey, C., Miller, S., Boyle, S. and Melville, C. (2007). A review of weight loss interventions for adults with intellectual disabilities. Obesity Reviews, 8: 339-345. https://doi.org/10.1111/j.1467-789X.2006.00307.x

[7] Scott, K. M., McGee, M. A., Wells, J. E., & Oakley Browne, M. A. (2008). Obesity and mental disorders in the adult general population. Journal of psychosomatic research, 64(1), 97–105. https://doi.org/10.1016/j.jpsychores.2007.09.006

[8] Avila, C., Holloway, A.C., Hahn, M.K. et al. An Overview of Links Between Obesity and Mental Health. Curr Obes Rep 4, 303–310 (2015). https://doi.org/10.1007/s13679-015-0164-9

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