Katherine M. Flegal · JAMA 2016 · Serial cross-sectional survey · n=26,468

Trends in Obesity Among Adults in the United States, 2005 to 2014

Cited 2838 times in the scientific literature.

Level 4 - case-series / case-control

Serial cross-sectional population survey (NHANES)

OpenAlex W2411583672 · doi:10.1001/jama.2016.6458 · record verified 2026-08-27

What was done

Researchers analyzed data from the National Health and Nutrition Examination Survey (NHANES), a cross-sectional, nationally representative survey of the US civilian noninstitutionalized population with measured height and weight. Data included 21,013 participants from 2005 through 2012 and 5,455 adults (2,638 men, mean age 46.8 years; 2,817 women, mean age 48.4 years) from 2013–2014. The study evaluated age-adjusted prevalence and 10-year linear trends (2005–2014) for overall obesity (BMI ≥30) and class 3 obesity (BMI ≥40), adjusting for age, sex, race/Hispanic origin, smoking status, and education.

What was found

In 2013–2014, the overall age-adjusted prevalence of obesity was 37.7% (95% CI, 35.8%–39.7%), with 35.0% (95% CI, 32.8%–37.3%) in men and 40.4% (95% CI, 37.6%–43.3%) in women. Class 3 obesity prevalence was 7.7% (95% CI, 6.2%–9.3%) overall, 5.5% (95% CI, 4.0%–7.2%) in men, and 9.9% (95% CI, 7.5%–12.3%) in women. From 2005 through 2014, adjusted analyses showed significant increasing linear trends among women for overall obesity (P = .004) and class 3 obesity (P = .01), but no significant trends among men (P = .30 for overall obesity; P = .14 for class 3 obesity).

Why it matters

These data show that the previously observed plateau in US obesity rates did not hold for women, who experienced significant increases in overall and severe obesity between 2005 and 2014.

Limits

The repeated cross-sectional design cannot evaluate individual weight trajectories over time or establish causal mechanisms. The survey excludes institutionalized populations, and adiposity was assessed solely by BMI without direct body composition measures.

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