DIFFERENTIAL RELATIONSHIP OF GENERALIZED AND ABDOMINAL OBESITY WITH DIABETIC RETINOPATHY

Abstract

Purpose: The relationship between obesity and diabetic retinopathy (DR) is equivocal in Asians. This study examined the associations between generalized (defined by body mass index [BMI]) and abdominal obesity (assessed as waist-hip ratio [WHR]) with DR.

Methods: We conducted a cross-sectional clinical study of 434 subjects with Type 2 Diabetes of Chinese, Malay and Indian ethnicity aged 18+ years (297 males; 137 females), from the Singapore National Eye Centre. DR was graded from retinal images using the modified Airlie House Classification into none; mild-moderate (early treatment of diabetic retinopathy study [ETDRS] 20-41); and vision-threatening DR (VTDR; ETDRS ≥51 and/or presence of clinically significant macular edema). BMI was calculated as (weight in kg)/(height in m)², while WHR was defined as waist/hip circumference (in cm). Binomial and multinomial logistic regression models were used to assess the associations of BMI and WHR with the presence and severity of DR, while adjusting for age, gender, ethnicity, insulin use, diabetes duration, HbA1c, systolic blood pressure, as well as each other (BMI and WHR) in the same model.

Results: There were 245 (56.4%) patients with DR, of which 140 (57.1%) had mild-moderate and 105 (42.9%) had VTDR. The median (interquartile range) for BMI and WHR were 25.7 (23.3-29.0) kg/m² and 0.94 (0.89-0.98), respectively. In multivariable models, higher BMI was associated with decreased odds of any and mild-moderate DR (odds ratio [95% confidence interval (CI)]: 0.92 [0.87-0.98]; and 0.92 [0.86-0.98] per kg/m² increase in BMI, respectively) but not VTDR. Due to a significant gender-WHR interaction, we conducted gender-stratified analyses and found a significant relationship between increased WHR and DR (odds ratio [95% CI]: 1.54 [1.08-2.19]; 2.65 [1.27-5.49]; and 2.61 [1.25-5.47] per 0.1 unit increase in WHR for any, mild-moderate and VTDR, respectively) in women, but not in men (odds ratio [95% CI]: 1.23 [0.77-1.96]; 1.09 [0.65-1.82]; and 1.58 [0.84-2.96] per 0.1 unit increase in WHR for any, mild-moderate and VTDR, respectively).

Conclusions: We found differential associations of BMI and WHR with DR; higher BMI was associated with lower odds of DR while higher WHR was associated with higher odds of DR in women but not in men. These results implicate abdominal obesity in the pathogenesis of DR in Asian women.