RESULTS— Prevalence of diabetes diagnosed
by a physician before NHANES III is
shown in Table 1. Prevalence was 5.1%
(95% CI 4.7–5.6) for all people 20 years of
age, 5.0% (4.4–5.6) for non-Hispanic
whites, 6.9% (6.2–7.7) for non-Hispanic
blacks, and 5.6% (5.1–6.2) for Mexican-
Americans. Prevalence rates increased with
age, although there was a slight decline at age
75 years for non-Hispanic blacks and
Mexican-Americans. Rates were similar in
men and women for non-Hispanic whites
but were higher in women for non-Hispanic
blacks and Mexican-Americans: the ratio of
the age-standardized rate in women vs. men
was 0.87 for non-Hispanic whites (NS), 1.25
for non-Hispanic blacks (P = 0.04), 1.41 for
Mexican-Americans (P = 0.003), and 0.98
for all races combined (NS). Prevalence was
lower in non-Hispanic whites: the age- and
sex - standardized prevalence ratio for non-
Hispanic whites vs. non-Hispanic blacks was
1.70 (P 0.0001) and vs. Mexican-Americans
was 1.92 (P 0.0001). The difference
between non-Hispanic blacks and Mexican-
Americans was not statistically significant .
When the rates in Table 1 were applied
to U.S. population projections for 1997,
the number of people 20 years of age who
have diagnosed diabetes was estimated to
be 7.5 million for non-Hispanic whites, 1.5