Obesity, BMI show inverse association with diabetic retinopathy

Obesity and BMI showed an inverse association with diabetic retinopathy among Asian adults, according to study results published in British Journal of Ophthalmology.

Charumathi Sabanayagam, MD, PhD, from the Singapore Eye Research Institute, and colleagues gathered data from 10,010 adults with diabetes from 12 population-based studies conducted among China, India, Japan, Singapore, South Korea and Asian populations in Russia.

When stratified by BMI categories, the prevalence of diabetic retinopathy was significantly lower among patients with obesity compared with those of normal weight. Pooled analysis additionally showed that obesity was not significantly correlated with diabetic retinopathy compared with normal weight, and continuous analysis showed an inverse relation between BMI and diabetic retinopathy.

Similarly, the prevalence for vision-threatening diabetic retinopathy was significantly lower among patients with obesity compared with those of normal weight, with inverse association found in pooled analysis for obesity and continuous analysis for BMI.

“This phenomenon, also known as ‘reverse epidemiology,’ has been observed in several chronic diseases, including diabetes and coronary heart disease,” Sabanayagam and colleagues wrote.

While the exact mechanism underlying the inverse association between diabetic retinopathy and either BMI or obesity is not clear, the researchers suggested three plausible explanations: survival bias, higher prevalence of comorbid conditions leading to diabetic retinopathy or genetic predisposition to type 2 diabetes.

“Our results warrant further research to elucidate the longitudinal association and evaluate the effect of weight reduction on development and progression of [diabetic retinopathy] in obese Asian adults with diabetes,” they wrote.