The World Health Organization estimates that diabetic retinopathy (DR) accounts for approximately 5% of the global prevalence of blindness, with estimates of 15% to 17% in developed countries.
In a recent study, researchers have found that levels of circulating vitamins C, D and E were comparatively low in patients with diabetic retinopathy (DR) than those without. The study findings were published in the American Journal of Ophthalmology on January 13, 2022.
Previous studies have shown that micronutrients are protective against diabetes mellitus (DM) development and its complications by modulating insulin sensitivity and maintaining pancreatic β-cell function. However, research on the real-world effects of micronutrients on DR remains understudied. Therefore, Dr Wei Wang and his team conducted a study to investigate the associations between circulating micronutrients (vitamins A, C, D, E and carotenoids) and risk of DR.
In a cross-sectional study, the researchers included 517 diabetic patients from the 2005-2006 National Health and Nutrition Examination Survey. They measured micronutrients using high performance liquid chromatography and converted serum vitamin D levels to liquid chromatography-tandem mass spectrometry-equivalent results. They determined the presence of DR based on non-mydriatic fundus photographs. They further performed a meta-analysis of relevant studies published between January 1, 1990, and December 31, 2020.
Key findings of the study:
Of the 517 patients, the researchers identified DR in 159 participants (25.17%).
Upon analysis, they found that serum vitamin C alone was found to be associated with a lower risk of DR after adjusting for multiple confounders.
In the meta-analysis, that included 35 studies comparing a total of 1,056 patients with DR and 920 controls, they noted that the pooled weighted mean difference (WMD) of vitamin C was -11.01.
However, they observed no associations between DR and circulating vitamin A or carotenoids.
The authors concluded, "This study demonstrated a significant inverse association between circulating vitamin C level and DR using a [US] population-based dataset. Lower levels of circulating vitamins C, D and E were found in DR patients than those without. More high-quality studies are required to assess the real effects of micronutrients on DR."
For further information:
DOI: https://doi.org/10.1016/j.ajo.2022.01.005