Has the prevalence of overweight, obesity and central obesity levelled off in the United States? Trends, patterns, disparities, and future projections for the obesity epidemic

Abstract

Background: Obesity (OB) is a serious epidemic in the United States.

Methods: We examined OB patterns and time trends across socio-economic and geographic parameters and projected the future situation. Large national databases were used. Overweight (OW), OB and severe obesity (SOB) were defined using body mass index cut-points/percentiles; central obesity (CO), waist circumference cut-point in adults and waist:height ratio cutoff in youth. Various meta-regression analysis models were fit for projection analyses.

Results: OB prevalence had consistently risen since 1999 and considerable differences existed across groups and regions. Among adults, men's OB (33.7%) and OW (71.6%) levelled off in 2009-2012, resuming the increase to 38.0 and 74.7% in 2015-2016, respectively. Women showed an uninterrupted increase in OB/OW prevalence since 1999, reaching 41.5% (OB) and 68.9% (OW) in 2015-2016. SOB levelled off in 2013-2016 (men: 5.5-5.6%; women: 9.7-9.5%), after annual increases of 0.2% between 1999 and 2012. Non-Hispanic Blacks had the highest prevalence in women's OB/SOB and men's SOB. OB prevalence in boys rose continuously to 20.6% and SOB to 7.5% in 2015-2016, but not in girls. By 2030, most Americans will be OB/OW and nearly 50% of adults OB, whereas ∼33% of children aged 6-11 and ∼50% of adolescents aged 12-19 will be OB/OW. Since 1999, CO has risen steadily, and by 2030 is projected to reach 55.6% in men, 80.0% in women, 47.6% among girls and 38.9% among boys. Regional differences exist in adult OB prevalence (2011-2016) and across ethnicities; South (32.0%) and Midwest (31.4%) had the highest rates.

Conclusions: US obesity prevalence has been rising, despite a temporary pause in 2009-2012. Wide disparities across groups and geographical regions persist. Effective, sustainable, culturally-tailored interventions are needed.

Keywords: Obesity; body mass index; central obesity; overweight; projection; trend.

Figure 1.

Secular trends in the prevalence (%) of obesity and severe obesity in US adults (≥20 years old) and youth (2–19 years old) by sex and ethnicity, National Health and Nutrition Examination Survey 1999–2016. The World Health Organization (WHO) defines adult obesity and the National Health, Lung, and Blood Institute classified extreme obesity by using BMI cut points of 30 and 40 kg/m², respectively. Childhood obesity [(BMI ≥95th percentile), and severe obesity (BMI ≥120% of the 95th percentile, or BMI ≥35kg/m², whichever was lower] were defined by the age-sex-specific BMI percentile in the 2000 Centers for Disease Control and Prevention growth charts. Analysis was stratified by sex and ethnicity for each age group, without adjusting for other socio-demographic groups, taking into account sampling design complexity.

Figure 2

Secular trends and ethnic disparities in the regional differences in prevalence (%) of obesity in US adults, Behavioral Risk Factor Surveillance System (BRFSS) 2011–2016. Secular trends (a) 2011, (b) 2013, (c) 2015, (d) 2016. Ethnic disparities using combined BRFSS 2014-2016 (e) non-Hispanic Whites, (f) non-Hispanic Blacks, (g) Hispanics. BMI of study participants was calculated based on reported weight and height. The improvement changes to the BRFSS affect obesity prevalence estimates, and mean that estimates from data collected in 2010 and before cannot be compared estimates from data collected in 2011 and thereafter. The World Health Organization (WHO) defines obesity as BMI ≥30 kg/m². Data source: Centers for Disease Control and Prevention (CDC). Prevalence of self-reported obesity among US adults by state and territory. Behavioral Risk Factor Surveillance System (BRFSS), 2017.