Objective: Physical activity may modify the association of adiposity with type 2 diabetes. We investigated the independent and joint association of adiposity and physical activity with fasting plasma glucose, impaired fasting glucose, and type 2 diabetes in a Chinese population.
Research design and methods: Middle-aged and older Chinese (n=28,946, ≥50 years, 72.4%women) from the Guangzhou Biobank Cohort Study were examined in 2003-2008. Multivariable regression was used in a cross-sectional analysis.
Results: BMI, waist circumference, and waist-to-hip ratio (WHR) were positively associated with type 2 diabetes after multiple adjustment, most strongly for WHR with odds ratio (OR) of 3.99 (95% CI 3.60-4.42) for highest compared with lowest tertile. Lack of moderate-to-vigorous physical activity, but not walking, was associated with diabetes with an OR of 1.29 (1.17-1.41). The association of moderate-to-vigorous activity with fasting glucose varied with WHR tertiles (P=0.01 for interaction). Within the high WHR tertile, participants who had a lack of moderate-to-vigorous activity had an OR of 3.87 (3.22-4.65) for diabetes, whereas those who were active had an OR of 2.94 (2.41-3.59).
Conclusions: In this population, WHR was a better measure of adiposity-related diabetes risk than BMI or waist circumference. Higher moderate-to-vigorous activity was associated with lower diabetes risk, especially in abdominally obese individuals.