Purpose: The purpose of this study was to explore whether there were gender differences in the relation of insulin resistance and beta-cell dysfunction to diabetic retinopathy among type 2 diabetic patients.
Methods: From 1999 to 2002, a screening regimen for diabetic retinopathy was performed by a panel of ophthalmologists using ophthalmoscopy and 45-degree color fundus photography to examine the fundus in a total of 971 type 2 diabetic patients examined between 1991 and 1993 in Kinmen, Taiwan. Seven hundred and twenty-five type 2 diabetic patients (301 males and 424 females) attended ophthalmological fundus checkup.
Results: The response rate in males and females was 71.3 and 77.2%. The proportion of diabetic retinopathy at the first eye screening was 16.3% in males and 20.1% in females. From the multiple logistic regression, the type of diabetes (known cases vs. new cases) was a significant factor of diabetic retinopathy in both males (OR = 3.65, 95% CI: 1.59-8.37) and females (OR = 3.66, 95% CI: 2.01-6.70). Diabetic retinopathy was also strongly affected by the homeostasis model assessment of insulin resistance (HOMA IR) and homeostasis model assessment of beta-cell dysfunction (HOMA beta-cell) (p < 0.0001 for trend test). In males, those who were in the 2nd quartile, 3rd quartile, and 4th quartile of HOMA IR had 4.87 times (95% CI: 1.18-20.11), 6.83 times (95% CI: 1.91-24.46), and 10.15 times (95% CI: 2.42-42.56) the risk for diabetic retinopathy as compared to those in the 1st quartile. There was a reduced risk for diabetic retinopathy in relation to HOMA beta-cell for the 2nd quartile, 3rd quartile, and 4th quartile of 86% (95% CI: 37-97%), 95% (95% CI: 77-99%), and 96% (95% CI: 78-99%) as compared to that in the 1st quartile. Only the 4th quartile had a significant risk (OR = 2.62, 95% CI: 1.17-5.86) for diabetic retinopathy as compared to that in the 1st quartile in females. The reduced risk for diabetic retinopathy found in relation to HOMA beta-cell for the 3rd and 4th quartiles were 66% (95% CI: 6-88%) and 66% (95% CI: 10-87%) as compared to that in the 1st quartile.
Conclusions: Gender differences in the relationship between insulin resistance/beta-cell dysfunction and diabetic retinopathy were demonstrated in type 2 diabetic patients.