Coffee cuts retinopathy risk in diabetes mellitus

In patients with diabetes mellitus, high daily consumption of coffee may decrease the risk of diabetic retinopathy (DR), reveals a recent Korea study.

Researchers conducted a cross-sectional analysis of 1,350 respondents who participated in the 2008–2011 Korean National Health and Nutrition Survey. Only those who had type 2 diabetes and had undergone DR examination were eligible for inclusion. DR was assessed according to the modified Airlie House classification system, while coffee intake was measured through food frequency questionnaires.

Twenty percent of study participants had DR, while vision-threatening DR was present in 5.3 percent. Most (87.8 percent) DR patients had non-proliferative DR. Glycated haemoglobin and diabetes duration were all higher in DR patients, while body mass index was slightly lower.

Multivariable logistic regression analysis found a significant and inverse correlation between coffee intake and DR (p_trend=0.025), such that participants who drank ≥2 cups per day were nearly 50-percent less likely to develop any DR than comparators who had almost no coffee consumption (adjusted odds ratio [OR], 0.53, 95 percent confidence interval [CI], 0.28–0.99).

A similar effect was reported for vision-threatening DR (≥2 vs almost no cups per day: adjusted OR, 0.30, 95 percent CI, 0.10–0.91; p_trend=0.05), but not for proliferative DR (p_trend=0.071).

“We also observed that, regardless of the type of coffee, the prevalence of DR tended to decrease with increases in coffee intake of both black coffee and coffee with sugar or cream, adjusted for confounders such as energy intake,” the researchers said. “Cohort studies are warranted to fully elucidate the cross-sectional association between coffee consumption and DR.”