Body mass index and retinopathy in Asian populations with diabetes mellitus

Body mass index (BMI) is an established risk factor for diabetes. However, the association between BMI and diabetic retinopathy (DR) has been inconclusive. We aimed to assess the association between BMI and DR in a large population-based sample of multi-ethnic Asian adults in Singapore. We examined 2,278 adults aged ≥40 years with diabetes who participated in three population-based studies conducted from 2004 to 2011: the Singapore Malay Eye Study, the Singapore Indian Eye Study, and the Singapore Chinese Eye Study. Retinal photographs taken from both eyes were graded for any and vision-threatening (VTDR) using the modified Airlie House Classification. BMI (kg/m²) was categorized into normal/underweight (<25), overweight (25–29.9), and obese (≥30). The prevalence rates of any and VTDR in the study population were 35.1 % and 9.1 %, respectively. The prevalence of any and VTDR decreased with increasing categories of BMI (P trend <0.001 and 0.005). In multivariable models adjusted for potential confounders, compared to those with normal weight, the odds ratio (95 % confidence interval) of any DR was 0.71 (0.57–0.88) for overweight and 0.70 (0.53–0.92) for obese. Corresponding estimates for VTDR were 0.84 (0.59–1.21) for overweight and 0.58 (0.35–0.94) for obese. The inverse association between BMI and any DR was consistently present when BMI was analyzed as a continuous variable and in analyses stratified by ethnicity and age. In a population-based sample of multi-ethnic Asian adults, BMI levels were inversely associated with any DR and VTDR.