Dietary Intakes of Choline and Betaine and Incidence of Type 2 Diabetes: Tehran Lipid and Glucose Study.

Background: Our knowledge for the possible link between choline and betaine and the risk of type 2 diabetes (T2D) is very limited and contradictory. This study aimed to investigate the prospective association of dietary choline and betaine intakes with the risk of T2D in a group of Tehranian adults. Methods: In this prospective study, 6022 eligible subjects aged ≥18 years were chosen from the participants of the Tehran Lipid and Glucose Study in a secondary analysis. Diet was assessed based on a valid and reliable semiquantitative food frequency questionnaire. At baseline and follow-up examinations, biochemical and anthropometric variables were assessed. Multivariable Cox proportional hazard regression models was used to estimate the new onset of T2D concerning choline and betaine intake. Results: The mean age ± SD of 2707 men and 3315 women were, respectively, 41.4 ± 14.2 and 39.1 ± 13.1. During a median follow-up of 6.63 years, 528 cases of T2D incidence were diagnosed. Participants with a higher intake of choline had a higher intake of protein, fiber, and B12 and a lower intake of energy and carbohydrates. After controlling of confounders a significant positive association was observed between choline intake and the hazard ratio (HR) of T2D across quartiles of choline intake [HR (CI) in the fourth quartile: 1.25 (1.14-1.38), P trend = 0.01], but this significant finding was not reported for betaine intake. For every 100 milligram increase in choline consumption, the HR of T2D increased significantly in all age, sex, and BMI subgroups. Conclusions: Choline consumption increased the risk of T2D in total population and subgroups. No statistically significant association was found between dietary betaine intake and the risk of T2D in total population and subgroups.