- The CDC recently released a data brief summarizing results from the NHANES 2015-2016 survey on obesity in the US. By percentage rates, adult and childhood obesity prevalence have risen since 2013-2014, now at 40% among adults (up 5% from 38%) and 19% in youth, up from 17% (nearly an 8% increase). The “NCHS data brief” characterizes these changes as “flat” and said “both are not statistically significant”– the same may have been said of individual years before but notably, since 1999-2000, adult obesity has risen 30% and youth 33%. Although this may be “flat”, we would have hoped for a “down” year.
- Overall, these 2015-2016 numbers are not only disappointingly high, they are also well above the Healthy People 2020 goals of 30.5% adult obesity prevalence and 14.5% childhood obesity prevalence and it seems safe to say at this point that those goals will not be met since every year since they were set, there have been increases rather than reductions in obesity prevalence.
- Although the “midcourse status” of “Healthy People” goals officially says there has been “little or no detectable change” for both “diabetes” and “nutrition and weight status,” we do not believe there is a enough resources or a healthy enough culture for the goals to have a clear chance of success. Also, adults with obesity has risen from 34% to now 40% - the “midcourse check” now reflects old data trending up but not statistically significant.
- Childhood obesity did not significantly increase between 2013-2014 and 2015-2016, but there is a worrisome upward trend. Obesity prevalence among preschool children (2-5 years) showed the biggest rise, from 9% in 2011-2014 to 14% in 2015-2016, which suggests that public health interventions must be implemented far earlier and that a far bigger investment must be made for other interventions.
- Non-Hispanic black and Hispanic individuals were disproportionately affected by the obesity epidemic in 2015-2016. For example, NHANES found adult obesity prevalence to be 47% among non-Hispanic blacks and Hispanics vs. 38% among non-Hispanic whites and only 13% among non-Hispanic Asians.
The CDC recently released a data brief summarizing results from the NHANES 2015-2016 survey on obesity in the US. Adult and childhood obesity rates did not budge since the NHANES 2013-2014 survey: Prevalence was 40% among adults and 19% in youth in 2015-2016 vs. 38% among adults and 17% in youth in 2013-2014. Neither of these temporal differences were statistically significant versus 2013-14 though presumably they were versus 2011-2012 (which the previous increases were also presumably characterized as not statically significant.
Notably, this nationwide data is based on more rigorous data collection – including standardized physical exams – than the CDC’s state-by-state data published last month alongside the Robert Wood Johnson Foundation’s (RWJF) State of Obesity paper, which relied on self-report and thus underestimated the size of the obesity epidemic. This earlier report listed adult obesity prevalence >20% in all US states/territories and >35% in Alabama, Arkansas, Louisiana, Mississippi, and West Virginia (which held the record-high 38% obesity prevalence in 2016).
A weighted average of the CDC’s state-by-state data wouldn’t yield a national adult obesity rate as high as 40%, but this is the real number we’ve been waiting for, and it’s a sign that stigma and under-diagnosis persist and are worsening versus previous years.
The 40% figure implies that our sense of urgency around obesity as a public health problem should remain very, very high, whereas the RWJF report featured a slightly more optimistic tone around “fragile progress.” The obesity prevalence between 2013-2014 and 2015-2016 does seem like good news, when spun a certain way, since this rate was on a steady climb in the 15 years between the NHANES 1999-2000 survey and the 2013-2014 survey. A leveling-off is an improvement over significant increases in the population with obesity, but we want to emphasize that the 2015-2016 numbers are still far too high, well above the Healthy People 2020 goals of 30.5% adult obesity prevalence and 14.5% childhood obesity prevalence. We need to start seeing marked declines year to year, and that will require far bigger investment in amplified prevention efforts, greater attention on obesity as a therapeutic area, and more interdisciplinary efforts across the public and private sectors.
- Breaking down the data into more specific age groups, the prevalence of obesity among adults age 40-59 was significantly higher than the prevalence among adults age 20-39, at 43% vs. 36%, respectively. The prevalence of obesity among youth age 6-11 and among adolescents age 12-19 was significantly higher than the prevalence among children age 2-5, at 18%, 21%, and 14%, respectively. No significant difference was observed between adults age 60+ (41% prevalence) and younger adult age groups.
- While not statistically significant, there is a worrisome upward trend in childhood obesity according to this latest NHANES survey. This increase occurred despite anti-childhood obesity efforts, including former First Lady Michelle Obama’s Let’s Move campaign. Obesity prevalence among preschool children (2-5 years-old) showed the biggest rise, from 9% in 2011-2014 to 14% in 2015-2016, which suggests that public health interventions must be implemented even earlier and that major societal changes should take place. Rates among children 6-11 years-old and among adolescents 12-19 years-old remained slightly more stable, around ~18% and ~21%, respectively.
- That said, the trends for youth do not look good. Specifically, the increase in youth as they age is worrying; the baseline rate is the same for both girls and boys to start - 14% in the 2-5 year old range, the same for girls as boys. Then rates for obesity in youth increase to 16% in the 6-11 year old range for girls and 20% for boys, followed by 20% and 21% for boys and girls in the 12-19 year old age range. Overall, the trend looks worse for girls.
- Race and Hispanic origin continue to be significant factors in obesity risk. Non-Hispanic blacks and Hispanics, both adults and children, were disproportionately affected by the obesity epidemic vs. non-Hispanic whites and non-Hispanic Asians. NHANES found adult obesity prevalence to be 47% among non-Hispanic blacks and Hispanics vs. 38% among non-Hispanic whites and only 13% among non-Hispanic Asians, though it’s important to keep in mind that a lower BMI in the Asian population is correlated with the same spike in type 2 diabetes risk as a higher BMI in other populations. Childhood obesity prevalence in 2015-2016 was 22% among non-Hispanic blacks and 26% among Hispanics vs. only 14% among non-Hispanic whites and 11% among non-Hispanic Asians.
- The data brief reports no significant effect of gender on obesity prevalence, nor were there significant interactions between gender/race or between gender/age, with one major exception: Among non-Hispanic black, non-Hispanic Asian, and Hispanic adults, obesity rate was significantly higher in women than in men, as reflected in the graph directly below.
Adult Obesity Prevalence in the US by Race and Gender (2015-2016)
Childhood Obesity Prevalence in the US by Race and Gender (2015-2016)
-- by Maeve Serino, Payal Marathe, and Kelly Close