Obesity rates are increasing among adolescents and adults, according to 2 studies published in JAMA.
In one study, Katherine M. Flegal, PhD, National Center for Health Statistics, and colleagues examined the prevalence of obesity among adult men and women, and then trends observed between 2005 and 2014. Data were obtained from the National Health and Nutrition Examination Survey (NHANES), a cross-sectional, nationally representative health examination survey of the US population. Measures of obesity (BMI ≥30) and class 3 obesity (BMI ≥40) were determined in 2638 men (mean age, 46.8 years) and 2817 women (mean age, 48.4 years) using NHANES data from 2013-2014 and obesity trends from 2005-2014.
The overall, age-adjusted prevalence of obesity was 37.7% among men and 35% among women. The corresponding prevalence of class 3 obesity overall was 7.7%; class 3 obesity prevalence was 5.5% among men and 9.9% among women.
“Analyses of changes over the decade from 2005 to 2014, adjusted for age, race/Hispanic origin, smoking status, and education, showed significant increasing linear trends among women for overall obesity and class 3 obesity, but not among men,” said Dr Flegal.
In a corresponding study, Cynthia L. Ogden, PhD, National center for Health Statistics, and colleagues conducted a similar analysis of obesity trends among children and adolescents.
“Obesity and extreme obesity in children and adolescents are associated with elevated blood pressure and abnormal fasting glucose and, long-term, often tracks into adulthood,” noted Dr Ogden. “In adults, obesity can result in increased morbidity and mortality.”
The researchers’ analyzed NHANES data, collected for children between 2 and 19 years of age, in the 1988-1994 and 2013-2014 surveys. Obesity was defined as a BMI “at or above the sex-specific 95th percentile on the CDC BMI-for-age growth charts,” according to the study, and extreme obesity was defined as a BMI at or greater than 120% of the same percentile.
Measurements were gathered from 40,780 children and adolescents (mean age, 11 years; 48.8% female). The researchers found that the prevalence of obesity in 2011-2014 among study participants was 17%; the prevalence of extreme obesity was 5.8%. In children 2 to 5 years of age, obesity increased from 7.2% in 1988-1994 to 13.9% in 2003-2004, then decreased to 9.4% in 2013-2014. Obesity in children 6 to 11 years of age increased from 11.3% in 1988-1994 to 19.6% in 2007-2008, with no further changes noted. Obesity increased in adolescents between 12 and 19 years of age from 10.5% in 1988-1994 to 20.6% in 2013-2014.
“In this nationally representative study … the prevalence of obesity in 2011-2014 was 17% and extreme obesity was 5.8%. Between 1988-1994 and 2013-2014, the prevalence of obesity increased until 2003-004 and then decreased in children aged 2 to 5 years,” Dr Ogden concluded.
Dr Flegal noted that additional studies would be needed to determine the reasons behind these trends in obesity.
- Flegal KM, Kruszon-Moran D, Carroll MD, et al. Trends in obesity among adults in the United States, 2005 to 2014. JAMA. 2016;315(21):2284-2291; doi: 10.1001/jama.2016.6458
- Ogden CL, Carroll MD, Lawman HG, et al. Trends in obesity among children and adolescents in the United States, 1988-1994 through 2013-2014. JAMA. 2016;315(21):2292-2299; doi: 10.1001/jama.2016.6361