Aim/introduction: We evaluated the association between hypertriglyceridemic waist (HTW) phenotype and the risks of type 2 diabetes in an Iranian high-risk population.

Materials and methods: We analyzed 7-year follow-up data (n = 1,865) in non-diabetic first-degree relatives of consecutive patients with type 2 diabetes aged 30-70 years. The primary outcome was the diagnosis of type 2 diabetes based on repeated oral glucose tolerance tests. We used multiple logistic regressions to estimate the odds ratio (OR) for incident type 2 diabetes across four groups according to baseline fasting serum triglycerides (TG) level and waist circumference (WC): normal WC and normal TG, normal WC and high TG, enlarged WC and normal TG, and HTW (enlarged WC high TG).

Results: The HTW phenotype at baseline was associated with the incidence of type 2 diabetes. Those with HTW were 2.4-fold (OR 2.36, 95% confidence interval 1.61-3.44), those with normal WC high TG were 1.9-fold (OR 1.87, 95% confidence interval 1.29-2.70) and those with enlarged WC but normal TG were 2.8-fold (OR 2.84, 95% confidence interval 1.96-4.13) more likely to develop type 2 diabetes than those with normal WC and normal TG.

Conclusions: These data provide further evidence that the HTW phenotype is a robust predictor of type 2 diabetes in high-risk individuals in Iran, and the predictive power is not higher than that of simple enlarged WC and normal TG, emphasizing the importance of enlarged WC to the development of type 2 diabetes.