A recent study may bring us closer to understanding the differences in epidemiologic patterns of diabetic retinopathy (DR) between males and females. The researchers examined whether men have higher inflammatory protein biomarker concentrations in their aqueous humor compared with women and found that men with diabetes but without DR exhibited higher concentration levels of several potential biomarkers.

The cross-sectional study included aqueous humor specimens from 59 adults, divided into three groups: no diabetes mellitus (DM), DM without DR and DM with proliferative diabetic retinopathy (PDR).

The researchers compared concentration values between males and females for each protein biomarker, but this turned up no discoveries in patients with no DM or with PDR. However, they made 24 discoveries in patients with DM without DR. Men had a concentration value for all 24 protein biomarkers than women, and of these 24 proteins, 12 showed significant association with sex. Biomarkers included chemokines, proteases, proteins involved in programmed cell death and a T-cell surface protein.

 “The underlying biological mechanisms for observed sex-based differences in DM, including our study's results, are not well understood,” the researchers wrote in their paper. “In general, men and women appear to be at higher risk for microvascular and macrovascular complications of DM, respectively. Sex hormones are thought to play an important role in these discrepancies.

“For example, in the setting of ocular diseases associated with impaired blood flow, estrogen appears to be protective because of its reduction in large ocular vessel vascular resistance,” they explained. “In contrast, higher levels of testosterone have been associated with DR incidence and severity. In addition, gender-specific factors associated with health such as risky behaviors, work and home life expectations, health care access and utilization, and compliance with physician recommendations are also important.”

The researchers concluded that males may have a more inflammatory disease phenotype in this patient group.