Association between sleep duration and diabetes mellitus: Isfahan Healthy Heart Program. 
Recent studies revealed an association between sleep disturbance and metabolic disorders, such as obesity and metabolic syndrome.  An aim of this study was to assess the relation between sleep duration and diabetes mellitus in a representative sample of the Iranian population.  Participants were 12514 individuals, (6123 men and 6391 women) studied in the baseline survey of a community based program entitled Isfahan healthy heart program (IHHP).  Sleep time was obtained by validated questionnaire.  Diabetes mellitus was defined as fasting glucose over 126 mg/dl or 2 hour post prandial glucose at glucose tolerance test over 200 mg/dl, or if the patient was on diabetic medication.  The relation between the sleep time and diabetes was examined using categorical logistic regression with adjustment for sex, body mass index and waist circumference.  Compared with those, sleeping 7-8 hours per night, the individuals with sleeping time of 5 hours or less and aged <60 years had an increased odd ratio for diabetes and an impaired glucose tolerance. ( OR = 1.37 and 95% CI = 1.13, 1.67).  Sleep duration of 5 hours or less in individuals under age 60 years is associated with an increased prevalence of diabetes mellitus and an impaired glucose tolerance test.  This finding should be confirmed in longitudinal studies.