Adherence to a healthy lifestyle and the risk of type 2 diabetes in Chinese adults: a prospective, longitudinal cohort study

Abstract

BackgroundAdherence to various healthy lifestyle factors has been associated with up to 90% reduction in type 2 diabetes incidence in US studies consisting mostly of white people; however, little is known about whether such protective effects persist in Chinese populations. We aimed to examine the associations of several modifiable dietary and lifestyle factors with the risk of type 2 diabetes and to estimate the proportion of people in which the disease that could be prevented by the adoption of a healthy lifestyle in Chinese adults. MethodsIn this cohort study, we prospectively examined associations between six lifestyle factors with type 2 diabetes in the China Kadoorie Biobank of 461 211 participants aged 30–79 years without diabetes, cardiovascular disease, or cancer at baseline. We defined low-risk lifestyle factors as: non-smoking or having stopped smoking for reasons other than illness; alcohol consumption of <30 g per day; upper quartile for physical activity; a diet rich in vegetables and fruits and low in red meat, with some replacement of rice with wheat; BMI between 18·5–23·9 kg/m2, and waist-to-hip ratio of less than 0·90 for men and less than 0·85 for women. FindingsDuring a median 7·2 years (range 0·0–9·5) of follow-up, we identified 8 784 patients with incident type 2 diabetes. In multivariable-adjusted analyses, the two strongest risk factors for development of type 2 diabetes were high BMI and waist-to-hip ratio (central adiposity). Heavy smoking was also associated with an increased risk of diabetes (HR 1·20 [95% CI 1·08–1·34]); whereas regular alcohol consumption, high physical activity, and a healthy dietary pattern were associated with a reduced risk of diabetes, independent of BMI and waist-to-hip ratio. The population attributable risks were 34·4% (95% CI 31·9–36·8%) for incident diabetes attributable to higher or lower than normal BMI and 39·8% (37·4–42·3) for the cases attributable to high central adiposity. The population attributable risk was 26·5 (15·3–36·9) for an unhealthy diet and 9·1 (5·2–13·1) for a low physical activity level. Compared with participants without any low-risk factors, a combination of three or more low-risk lifestyle factors was associated with an 80% reduction in the risk of diabetes (hazard ratio 0·20; 95% CI 0·19–0·22). The population attributable risk was approximately 72·6% (95% CI 64·2–79·3) for incident diabetes attributable to a combination of BMI, waist-to-hip ratio, diet, and physical activity. Further inclusion of non-smoking and light-to-moderate alcohol consumption added little to the increase in population attributable risk (78·8% [95% CI 67·9–86·3]). The population attributable risks for diabetes seemed to be similar for men and women, and higher among urban, older, and obese participants. InterpretationOur findings indicate that adherence to a healthy lifestyle (maintaining lean body weight without central adiposity, having a healthy diet, and being physically active) might substantially lower the burden of type 2 diabetes in Chinese adults. FundingNational Natural Science Foundation of China), UK Wellcome Trust, Kadoorie Charitable Foundation, and State Scholarship Fund of China Scholarship Council.