Obesity Projected to Affect Half of All Adults in the US by 2030

Zachary J. Ward, MPH

Obesity, among the greatest public health epidemics to affect Americans in the past decade, is projected to increase into the 2030s.

A new study from investigators at the Harvard TH Chan School of Public Health in Boston showed estimates that nearly half of all US adults will have obesity in the next 10 years. The prevalence will be greater than 50% in 29 states, and no less than 35% in any other state.

The findings, reported by Zachary J. Ward, MPH, and colleagues, provide some of the first by-state projection data of US obesity and severe obesity rates, and add to the growing call for improved public health efforts to prevent the epidemic’s spread.

The team used body-mass index (BMI) data of the 6.2 million-plus adults to participate in the Behavioral Risk Factor Surveillance System Survey from 1993-1994 and 1999-2015 to compile their projection assessment. They corrected the data for quantile-specific self-reporting bias via measured data from 57,131 adults who participated in the National Health and Nutrition Examination Survey.

Multinomial regressions for each state and subgroup were fitted in order to estimate the prevalence of 4 BMI categories: underweight or normal weight (BMI <25); overweight (25 to <30); moderate obesity (30 to <35); severe obesity (>35). The categories were estimated from 1990-2030. In order to evaluate the approach’s accuracy, they predicted 2016 outcomes using data from 1990 through 2010.

Ward and colleagues reported through their assessment, with high predictive accuracy, that 48.9% of all adults (95% CI, 47.7—50.1) will have obesity by 2030. Another 24.2% (95% CI, 22.9 – 25.5) will have severe obesity by that time, and the prevalence will be greater than 25% in half of all states.

Among states, Oklahoma (58.4%; 95% CI, 56.4-60.2) is predicted to have the greatest rate of adults with obesity, closely followed by Alabama, Arkansas, and Mississippi (58.2% for all). Oklahoma and Mississippi are also projected to 31.8% (95% CI, 29.7-33.9) of all adults have severe obesity by that same time; Louisiana is projected to have 31.2%.

The states with the predicted lowest rates of obesity and severe obesity among their population are Colorado (38.2%; 14.3%, respectively), California (41.5%; 16.1%), and Hawaii 41.3%; 17.5%).

The greatest rate of men are projected to be overweight (32.5%; 95% CI, 31.2-33.8), while the greatest rate of women are projected to have severe obesity (27.6%; 95% CI, 26.1-29.2).

Investigators noted these troubling findings echo a previous estimate showing 57% of children aged 2-19 years old will have obesity by age 35. They stressed concern over the fact that severe obesity is rising greatly in prevalence—to a rate which was seen in obesity, in 1990.

Even worse, the burden of severe obesity is being observed in populations less-suited to manage it.

“In addition to the profound health effects, such as increased rates of chronic disease and negative consequences on life expectancy, the effect of weight stigma may have far-reaching implications for socioeconomic disparities as severe obesity becomes the most common BMI category among low-income adults in nearly every state,” they wrote.

The shift in prevalence from overweight to obesity—and eventually from obesity to severe obesity&mdash;signifies patients’ issues with successfully losing weight. As such, the investigators emphasized the need for more preventive measures.

Everything from policy- and environmental-level interventions, as well as cost-effective preventive care—would be bettered with consideration to social and cultural determinants of obesity, they wrote.

The study, “Projected U.S. State-Level Prevalence of Adult Obesity and Severe Obesity,” was published online in The New England Journal of Medicine.