Context The prevalence of obesity and overweight increased in the United States
between 1978 and 1991. More recent reports have suggested continued increases
but are based on self-reported data.
Objective To examine trends and prevalences of overweight (body mass index [BMI]
≥25) and obesity (BMI ≥30), using measured height and weight data.
Design, Setting, and Participants Survey of 4115 adult men and women conducted in 1999 and 2000 as part
of the National Health and Nutrition Examination Survey (NHANES), a nationally
representative sample of the US population.
Main Outcome Measure Age-adjusted prevalence of overweight, obesity, and extreme obesity
compared with prior surveys, and sex-, age-, and race/ethnicity–specific
estimates.
Results The age-adjusted prevalence of obesity was 30.5% in 1999-2000 compared
with 22.9% in NHANES III (1988-1994; P<.001).
The prevalence of overweight also increased during this period from 55.9%
to 64.5% (P<.001). Extreme obesity (BMI ≥40)
also increased significantly in the population, from 2.9% to 4.7% (P = .002). Although not all changes were statistically significant,
increases occurred for both men and women in all age groups and for non-Hispanic
whites, non-Hispanic blacks, and Mexican Americans. Racial/ethnic groups did
not differ significantly in the prevalence of obesity or overweight for men.
Among women, obesity and overweight prevalences were highest among non-Hispanic
black women. More than half of non-Hispanic black women aged 40 years or older
were obese and more than 80% were overweight.
Conclusions The increases in the prevalences of obesity and overweight previously
observed continued in 1999-2000. The potential health benefits from reduction
in overweight and obesity are of considerable public health importance.