For men in each race-ethnic group, the prevalence
of class I obesity (BMI 30.0±34.9) ®rst increased
steadily by age group, reaching a maximum in
middle age, and then declined steadily thereafter.
The pattern for women was generally similar, but
with less of a decline with age. For non-Hispanic
whites, the prevalence of BMI 30.0±34.9 for women
was similar to, or lower than, that for men. For nonHispanic
blacks and Mexican Americans, however,
the prevalence of BMI 30.0±34.9 tended to be higher
for women than for men. Differences among raceethnic
groups in the prevalence of BMI 30.0±34.9
were much more pronounced for women than for men.
The prevalence of BMI 30.0±34.9 was signi®cantly
higher for non-Hispanic black and Mexican-American
women than for non-Hispanic white women. This
pattern was similar for all age groups.
The prevalences of class II obesity (BMI 35.0±
39.9) and class III obesity (BMI ^ 40.0) showed no
strong age trends, although both tended to increase
by age group up to middle age, and then to decline.
With few exceptions, within each race-ethnic group,