Long-term Diet Quality and Risk of Type 2 Diabetes Among Urban Chinese Adults

OBJECTIVE: Little evidence exists regarding long-term diet quality and the risk of type 2 diabetes among Asian populations, who have undergone a nutrition transition and a diabetes epidemic. RESEARCH DESIGN AND METHODS: A total of 117,919 Chinese men and women, 40–74 years old, free of diabetes, cardiovascular disease, and cancer at baseline, were followed from 1996 to 2015. Diet quality was assessed by a healthy diet score (HDS) based on eight commonly consumed food groups previously suggested to be related to diabetes. Long-term diet quality and its changes were assessed by repeated surveys using food-frequency questionnaires. RESULTS: We identified 6,111 incident diabetes cases during a mean follow-up of 11.5 years. Higher HDS was associated with lower diabetes risk (hazard ratio [HR] 0.85 [95% CI 0.78–0.92] in the highest vs. lowest quintile, P(continuous) <0.0001) after adjustment for potential confounders including BMI. Maintaining a high HDS during follow-up was associated with 26% lower risk compared with a consistently low HDS (HR 0.74 [95% CI 0.63–0.85]). The inverse association between HDS and diabetes was observed regardless of participants’ age, sex, smoking and exercise habits, obesity status, and metabolic disease status but was more prominent among those who participated in leisure-time exercise (P(interaction) = 0.004). When considered jointly, a sustained high HDS plus exercise was associated with a 45% reduced risk of diabetes (HR 0.55 [95% CI 0.45–0.67]). CONCLUSIONS: A high-quality diet, especially maintained over the long term and in conjunction with leisure-time exercise, is associated with lower risk of type 2 diabetes among urban Chinese adults.