Sex-specific incidence rates and risk factors of insulin resistance and -cell dysfunction: a decade follow-up in a Middle Eastern population

AimsTo examine the incidence of and risk factors for insulin resistance and -cell dysfunction in a representative Iranian population over a median follow-up of 9.2 years. MethodsIn total, 3662 people (1528 men) without known diabetes with a baseline homeostasis model assessment of insulin resistance (HOMA-IR) level < 75th percentile and, when -cell dysfunction was the outcome of interest, 3664 people (1530 men) with a homeostasis model assessment of -cell function (HOMA-) level 25th percentile were included in the study (HOMA-IR < 2.20 and HOMA- 64.3 among men, and HOMA-IR < 2.39 and HOMA- 81.7 among women). ResultsThe incidence rates of insulin resistance and -cell dysfunction were 56.3 and 33.6/1000 person-years among men and 48.6 and 50.3/1000 person-years among women, respectively. Applying multivariable Cox regression in both sexes, fasting insulin, triglyceride/HDL cholesterol ratio and lower education were positive predictors of insulin resistance, whereas age was a negative predictor. Moreover, fasting plasma glucose, waist-to-height ratio, wrist circumference and lower hip circumference were significantly associated with incident insulin resistance only among women (all P < 0.05). Considering -cell dysfunction in both sexes, age and fasting plasma glucose increased the risk, whereas 2-h post-challenge plasma glucose was a positive predictor only among men, and waist-to-height ratio and triglyceride/HDL cholesterol ratio were negative predictors only among women (all P < 0.05). ConclusionsModifiable risk factors are related to the incidence of insulin resistance and -cell dysfunction, which can be prevented with proper strategies although the difference between men and women should be taken into account.