The high rates of abnormal fasting and postchallenge glucose found in NHANES III, together with the increasing frequency of obesity and sedentary lifestyles in the population, make it likely that diabetes will continue to be a major health problem in the U.S.

In 2011-2012, the estimated prevalence of diabetes was 12% to 14% among US adults, depending on the criteria used, with a higher prevalence among participants who were non-Hispanic black, non-Hispanic Asian, and Hispanic. Between 1988-1994 and 2011-2012, the prevalence of diabetes increased in the overall population and in all subgroups evaluated.

OBJECTIVE -The purpose of this study was to examine the prevalences of diagnosed and undiagnosed diabetes, and impaired fasting glucose (IFG) in U.S. adults during 1999 -2002, and compare prevalences to those in 1988 -1994. RESEARCH DESIGN AND METHODS -The National Health and Nutrition Examination Survey (NHANES) contains a probability sample of adults aged Ն20 years. In the NHANES 1999NHANES -2002,761 adults were classified on glycemic status using standard criteria, based on an interview for diagnosed diabetes and fasting plasma glucose measured in a subsample.RESULTS -The crude prevalence of total diabetes in 1999 -2002 was 9.3% (19.3 million, 2002 U.S. population), consisting of 6.5% diagnosed and 2.8% undiagnosed. An additional 26.0% had IFG, totaling 35.3% (73.3 million) with either diabetes or IFG. The prevalence of total diabetes rose with age, reaching 21.6% for those aged Ն65 years. The prevalence of diagnosed diabetes was twice as high in non-Hispanic blacks and Mexican Americans compared with non-Hispanic whites (both P Ͻ 0.00001), whereas the prevalence of undiagnosed diabetes was similar by race/ethnicity, adjusted for age and sex. The prevalence of diagnosed diabetes was similar by sex, but prevalences of undiagnosed diabetes and IFG were significantly higher in men. The crude prevalence of diagnosed diabetes rose significantly from 5.1% in 1988 -1994 to 6.5% in 1999 -2002, but the crude prevalences were stable for undiagnosed diabetes (from 2.7 to 2.8%) and IFG (from 24.7 to 26.0%). Results were similar after adjustment for age and sex.CONCLUSIONS -Although the prevalence of diagnosed diabetes has increased significantly over the last decade, the prevalences of undiagnosed diabetes and IFG have remained relatively stable. Minority groups remain disproportionately affected. Diabetes Care 29:1263-1268, 2006D iabetes and its complications are major causes of morbidity and mortality in the U.S. (1). The economic cost of diabetes in medical expenditures and lost productivity was estimated to be $132 billion in the U.S. in 2002 (2). Nationally the prevalence of self-reported diagnosed diabetes has steadily increased over time (3), but the extent to which this increase is due to enhanced detection is uncertain. Undiagnosed diabetes and impaired fasting glucose (IFG) also have important health consequences (4,5). Only one nationally representative survey, The National Health and Nutrition Examination Survey (NHANES), examines both diagnosed diabetes and undiagnosed diabetes. This survey showed that from 1988 to 1994, undiagnosed diabetes comprised approximately one-third of total diabetes (diagnosed and undiagnosed) in U.S. adults (6). The prevalence of IFG was nearly as high as the prevalence of total diabetes. In 1999, the NHANES became a continuous annual survey with data released every 2 years, and we reported the prevalence of diagnosed diabetes, undiagnosed diabetes, and IFG in adults based on data from 1999 to 2000 (7). The limited sample size in these 2 years, however, restricted the detail a...