Objective: To determine the prevalence of risk factors for non-insulin-dependent diabetes mellitus (NIDDM) and the frequency of screening for NIDDM in U.S. adults.
Research design and methods: A detailed questionnaire was administered to a representative sample of 19,680 adults > or = 18 years of age who reported no medical history of diabetes in the 1989 National Health Interview Survey (NHIS). Information was obtained on risk factors for diabetes, complications related to diabetes, and whether the subjects had been screened for diabetes in the past year. Women reporting pregnancy in the past year were excluded from analysis. The prevalence of undiagnosed NIDDM according to the frequency of risk factors for NIDDM was determined based on oral glucose tolerance data from the National Health and Nutrition Examination Survey (NHANES) II and Hispanic Health and Nutrition Examination Survey (HHANES).
Results: Prevalence of undiagnosed NIDDM based on the NHANES II and HHANES increased with age, obesity, and family history of diabetes, reaching 11.7% in people with all three risk factors. Based on the NHIS, 77.5% of U.S. adults with no medical history of diabetes (131 million people) had at least one risk factor for NIDDM or complication related to NIDDM, and 22.9% (38 million people) had three or more risk factors or complications. Approximately 31% of adults reported being screened for diabetes in the past year. Screening rates increased with an increasing number of risk factors, but even among those with three risk factors, only 38.6% were screened for NIDDM.
Conclusions: More than 7 million U.S. adults have undiagnosed NIDDM. Nevertheless, screening for diabetes in high-risk groups occurs substantially less frequently than necessary to detect undiagnosed NIDDM and institute appropriate hypoglycemic treatment.