Morbid obesity rates continue to rise rapidly in the United States

Abstract

Clinically severe or morbid obesity (body mass index (BMI) >40 or 50 kg m(-2)) entails far more serious health consequences than moderate obesity for patients, and creates additional challenges for providers. The paper provides time trends for extreme weight categories (BMI >40 and >50 kg m(-2)) until 2010, using data from the Behavioral Risk Factor Surveillance System. Between 2000 and 2010, the prevalence of a BMI >40 kg m(-2) (type III obesity), calculated from self-reported height and weight, increased by 70%, whereas the prevalence of BMI >50 kg m(-2) increased even faster. Although the BMI rates at every point in time are higher among Hispanics and Blacks, there were no significant differences in trends between them and non-Hispanic Whites. The growth rate appears to have slowed down since 2005. Adjusting for self-report biases, we estimate that in 2010 15.5 million adult Americans or 6.6% of the population had an actual BMI >40 kg m(-2). The prevalence of clinically severe obesity continues to be increasing, although less rapidly in more recent years than prior to 2005.

Figure 1. Prevalence growth by severity of obesity (in percent over 1986 baseline)

Notes: Author's calculation based on Behavioral Risk Factor Surveillance Survey, BMI cutpoints calculated based on self-reported height and weight. Adjusted line (squares) uses cutpoint of 37.3 for men and 37.0 for women to make it comparable to BMI>40 calculated from objective height and weight measurement. 200 indicates a 200% increase over baseline, i.e. a tripling of baseline rates.