Relationship of Carbohydrate Intake Proportion to Cardiovascular Events in Japanese People With Type 2 Diabetes Mellitus

Abstract

Background: It remains largely unknown whether a low-carbohydrate diet is associated with cardiovascular disease and all-cause mortality, and also if low-carbohydrate diets consisting of different nutrients could have different effects on these outcomes in people with type 2 diabetes. Objective: This prospective observational study investigated which lifestyle habits were associated with an increased risk of health outcomes. Methods: The study participants comprised 731 Japanese outpatients with type 2 diabetes and no evident cardiovascular disease history. Lifestyle habits, including diet, were assessed with questionnaires at baseline and at years 2 and/or 5, and their mean values were calculated using the average value of lifestyle factors from baseline to the date of onset of an event or the end of follow-up. A multivariable Cox proportional hazards model was used to determine the relationships between each lifestyle habit and the primary endpoint events, comprising cardiovascular events and all-cause mortality. Results: During the mean follow-up period of 7.5 ± 2.4 years, composite primary endpoint events occurred in 55 participants. Multivariate Cox models showed a significant positive association between the mean proportion of carbohydrate intake and the primary endpoint incidence (hazard ratio = 1.06; 95% CI, 1.02-1.10; P = .005); in addition, the mean total low-carbohydrate diet score, animal low-carbohydrate diet score, and mean proportion of saturated fatty acid intake showed significant inverse associations with the incidence of the primary endpoint. Conclusion: Our data demonstrated that a higher proportion of carbohydrate intake, particularly with reduced consumption of animal-derived fat/protein, was correlated with an increased risk of cardiovascular disease and all-cause mortality. These data underscore the need to consider dietary components in people with type 2 diabetes.