Dietary carbohydrate intake and new-onset diabetes: A nationwide cohort study in China

Aim The association of carbohydrate intake with diabetes risk remains uncertain. We aimed to evaluate the prospective associations of the amount and types of carbohydrate intake with new-onset diabetes. Methods A total of 16,260 non-diabetic participants from the China Health and Nutrition Survey (CHNS) were included. Dietary intake was collected by three consecutive 24-h dietary recalls combined with a household food inventory. Participants with self-reported physician diagnosed diabetes, or fasting plasma glucose ≥7.0 mmol/L or glycated hemoglobin ≥6.5% during the follow-up were defined having new-onset diabetes. Results During a median follow-up of 9 years (158,930 person-years), 1100 participants developed diabetes. Overall, there was a U-shaped association between percent of energy from carbohydrate intake and new-onset diabetes, with minimal risk at 49–56% of energy from total carbohydrate intake (quartile 2) (P for nonlinearity <0.001). Moreover, there was an L-shaped association between high-quality carbohydrate intake and new-onset diabetes (P for nonlinearity <0.001), and a J-shaped association of low-quality carbohydrate intake with new-onset diabetes (P for nonlinearity <0.001). Furthermore, there was an inverse association between the plant-based low-carbohydrate diet scores for low-quality carbohydrate and new-onset diabetes. However, a reversed J-shaped association was found between the animal-based low-carbohydrate diet scores for low-quality carbohydrate and new-onset diabetes (P for nonlinearity <0.001). Conclusions There was a U-shape association between percent of total carbohydrate intake and new-onset diabetes, with the lowest risk at 49–56% carbohydrate intake. Our findings provide some evidence for the intake of high-quality carbohydrate, and the substitution of plant-based products for low-quality carbohydrate for primary prevention of diabetes.