The study uncovered differences by race and education level in lifetime obesity status.
A study of US health data shows that half the population has been obese at some point, which means Americans could face greater health risks than previously thought. The findings appear in the American Journal of Preventive Medicine.
Researchers led by Andrew Stokes, PhD, of Boston University School of Public Health, evaluated data from the National Health and Nutrition Examination Survey from 1988 through 2014, examining body mass index (BMI) data for men and women and excluding data for women when they were pregnant. They found that 50.8% of men and 51.6% of women had been obese at some point, although 22% of those who had once been obese no longer were.
However, certain diseases associated with weight loss were more prevalent among older people who had been obese but had since lost weight, including smokers. These conditions included sarcopenia, which accelerates the loss of lean muscle mass and is associated with poor nutrition, inflammation, and cognitive decline.
Obesity is associated with a host of health effects, including diabetes and heart disease, sleep apnea, and depression. While losing weight can alleviate many health effects, some are cumulative, and the damage lingers after weight loss. Thus, the authors argue, a person who was formerly obese may be at higher risk for some health outcomes than a person who has never been obese, and it makes sense for public health officials to track people who have been obese at any point.
The study revealed racial and ethnic differences in obesity history, as well as differences among women by education level. Among white women, 51% had never been obese, while this was true for only 30.4% of African American women, and only 19.3% ever ceased being obese. Asian American women were the least likely to ever become obese—69% had never been obese.
Attending college made women less likely to become obese, but the same was not true for men. Smoking status also decreased the likelihood of current obesity, although paradoxically, current smokers were more likely to have been obese at some point.
The age range with the greatest likelihood of obesity was 55 to 69. Obesity peaked in these years, then tapered off, so that after age 80, there were more people who were formerly obese than currently obese.
“The population burden of obesity is larger than indicated by data on current BMI alone,” the authors concluded. “The formerly obese population, which accounts for the gap between these two estimates, is an important and growing minority of the population with elevated disease risks.”
Stokes A, Ni Y, Preston SH. Prevalence and trends in lifetime obesity in the US, 1988-2014 [published online September 5, 2017]. Am J Prev Med. 2017; DOI: http://dx.doi.org/10.1016/j.amepre.2017.06.008