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.