[High prevalence of diabetes and abnormal glucose tolerance in urban Iranians aged over 20 years: determining an effective screening strategy for un-diagnosed diabetes]

ABSTRACT

The aim of this study was to determine the prevalences of diagnosed and undiagnosed diabetes mellitus, impaired fasting glucose [IFG], impaired glucose tolerance [IGT], and combined IFG/IGT and to develop an effective screening strategy for undiagnosed diabetes in a large urban Iranian community. The study population included 9,519 participants of the Tehran Lipid and Glucose Study, aged > 20 years, with full relevant clinical data. Age-standardized prevalence of diabetes and glucose intolerance categories were reported according to the 2003 American Diabetes Association definitions. The numbers needed to screen [NNTS] to find one person with undiagnosed diabetes were estimated from age-adjusted logistic regression models. The prevalences of diagnosed and undiagnosed diabetes, isolated IFG, isolated IGT, and combined IFG/IGT were 8.1%, 5.1%, 8.7%, 5.4% and 4.0% in men and 10%, 4.7%, 6.3%, 7.6%, and 4.5% in women respectively. Un-diagnosed diabetes was associated with family history of diabetes, increased body mass index [BMI >/= 25 kg/m2], abdominal obesity, hypertriglyceridemia, hypertension and low HDL-C levels. Among men, a combination of increased BMI, hypertension, and family history of diabetes led to an NNTS of 1.6 [95%CI 1.57-1.71] and among women a combination of family history of diabetes and abdominal obesity, yielded an NNTS of 2.2 [95%CI 2.1-2.4]. Approximately 32% of Tehranian adults had either diabetes or some degree of other glucose tolerance abnormalities. Nearly 40% of total cases with diabetes were undiagnosed. Screening individuals with family history of diabetes, BMI25 kg/m2, abdominal obesity and hypertension may have substantial advantages