THE ONSET OF NIDDM AND ITS RELATIONSHIP TO CLINICAL-DIAGNOSIS IN EGYPTIAN ADULTS

The onset of diabetes relative to clinical diagnosis was estimated in Egyptians with noninsulin-dependent diabetes mellitus (NIDDM) based on the relationship between retinopathy and duration of diabetes. Betwee n July 1992 and October 1993 the Diabetes in Egypt (DIE) Project perfo rmed a cross-sectional, population-based survey with clinical and labo ratory follow-up to describe the prevalence of microvascular, neuropat hic, and macrovascular complications among Egyptians greater than or e qual to 20 years of age with diagnosed diabetes, previously undiagnose d diabetes, impaired glucose tolerance, and normal glucose tolerance. The sample of persons with diabetes diagnosed prior to the survey had medical examinations which included a dilated eye examination and reti nal photographs. Generalized linear models were used to relate the pro bability of retinopathy to duration of diabetes. Among 218 persons wit h diabetes diagnosed prior to the DIE project, 87 (40 %) had diabetic retinopathy. The onset of retinopathy was estimated to occur 2.6 years (p = 0.04) prior to clinical diagnosis. The estimated annual incidenc e of retinopathy was 5 % and the estimated prevalence at the time of c linical diagnosis of diabetes was 12 %. On the basis of reports that r etinopathy does not occur until approximately 5 years after the develo pment of diabetes, the onset of NIDDM was estimated to occur 7.6 years prior to its clinical diagnosis. This estimate of the onset of NIDDM in Egyptians is comparable to other estimates reported for US and Aust ralian populations.