Impact of classical risk factors of type 2 diabetes among Asian Indian, Chinese and Japanese populations

Aims: This review investigated the population impact of major modifiable type 2 diabetes (T2D) risk factors, with special focus on native Asian Indians, to estimate population attributable risks (PARs) and compare them with estimates from Chinese and Japanese populations. Methods: Information was obtained on risk factors in 21,041 Asian Indian, 17,774 Chinese and 17,986 Japanese populations from multiple, large, cross-sectional studies (the DECODA project) of T2D. Crude and adjusted PARs were estimated for the major T2D risk factors. Results: Age had the highest crude and adjusted PARs among Asian Indians and Chinese in contrast to waist-hip ratio among Japanese. After adjusting for age, the PAR for body mass index (BMI) in Asian Indians (41.4% [95% CI: 37.2%; 45.4%]) was second only to triglycerides (46.4% [95% CI: 39.5%; 52.8%]) compared with 35.8% [95% CI: 29.9%; 41.4%] in Japanese and 38.4% [95% CI: 33.5%; 43.2%] in Chinese people. The PAR for BMI adjusted for age, LDL and triglycerides (39.7% [95% CI: 31.6%; 47.2%]) was higher than for any other factor in Asian Indians, and was much higher than in the Chinese (16.8% [95% CI: 3.0%; 30.9%]) and Japanese (30.4% [95% CI: 17.5%; 42.2%]) populations. Conclusion: This review provides estimates of the association between major risk factors and prevalences of T2D among Asian populations by examining their PARs from large population-based samples. From a public-health point of view, the importance of BMI in Asian Indians is especially highlighted in comparison to the other Asian populations. Given these results and other recent findings on the causality link between BMI and T2D, it can be postulated that obesity may be involved in the aetiology of T2D through interaction with ethnic-specific genetic factors, although ethnicity itself is not a direct risk factor for T2D as people of all ethnic backgrounds develop diabetes.