DURHAM, N.C. — An analysis of National Health and Nutritional Examination Survey (NHANES) data for 2015-2016 shows the incidence of childhood obesity continues to rise. Researchers at the Duke University Clinical Research Institute (D.C.R.I.) identified “notable spikes” between 2014 and 2016 in obesity for preschool boys and girls aged 16 to 19.
The study was based on body-mass index (B.M.I.) data for 3,340 children participating in the NHANES database, which is updated every two years. The researchers examined data back to 1999 that includes 33,543 children.
“About four years ago, there was evidence of a decline in obesity in preschoolers,” said Asheley Cockrell Skinner, Ph.D., lead author and associate professor of population health sciences, who is also a member of the Duke Clinical Research Institute. “It appears any decline that may have been detected by looking at different snapshots in time or different data sets has reversed course. The long-term trend is clearly that obesity in children of all ages is increasing.”
The findings, which appear Feb. 26 in the journal Pediatrics, show 35.1% of children in the United States were overweight in 2016, a 4.7% increase compared to 2014. Boys and girls aged 16 to 19 had the highest rates of any age group in 2016, with 41.5% considered overweight, defined by the Centers for Disease Control and Prevention (C.D.C.) as having a B.M.I. at or above the 85th percentile for age and sex. Among the 16-to-19-year-olds, 4.5% have Class III obesity, the highest of three categories defined by the C.D.C.
Across all age groups, African-American and Hispanic children had higher rates of overweight and all levels of obesity, while Asian-American children had markedly lower rates. The most prominent trend since 1999 is the increase in all levels of overweight for Hispanic girls, and overweight and Class II obesity (B.M.I. that is at least 120% above the 95th percentile for age and sex) among Hispanic males.
The researchers said the study has limitations, relying on two-year data that provides snapshots in time across a wide population. But Dr. Skinner said the NHANES database is a broader data source than sources for studies that have found declines in obesity rates among smaller or segmented populations. The NHANES 2015-16 data is also the first to include enough data to create a nationally representative sample in Asian-American children, the race or ethnic group showing the obesity rare lowest, at 23.2%.
“Despite some previous reports, the obesity epidemic has not abated,” said senior author Sarah C. Armstrong, M.D., associate professor of pediatrics who is also a member of the D.C.R.I. “This evidence is important in keeping the spotlight shined on programs to support healthy changes. Obesity is one of the most serious health challenges facing children and is a predictor for many other health problems. When we see that leveling off, we can become complacent — we can’t afford to do that.”