Abstract
Purpose:
To investigate the associations between circulating micronutrients (vitamins A, C, D, E and carotenoids) and risk of diabetic retinopathy (DR).
Design:
Cross-sectional study and meta-analysis.
Methods:
The cross-sectional study included 517 diabetic participants aged 40 years and older in the 2005-2006 National Health and Nutrition Examination Survey. Serum vitamin D was converted to liquid chromatography-tandem mass spectrometry-equivalent results, while other micronutrients were measured using high performance liquid chromatography. Presence of DR was determined based on non-mydriatic fundus photographs. A meta-analysis was subsequently performed which included relevant studies published from 1 January 1990 to 31 December 2020.
Results:
Of the 517 included participants, DR was identified in 159 participants (25.17%). After adjusting for multiple confounders, only serum vitamin C was associated with a lower risk of DR (odds ratio [OR]: 0.60; 95% confidence interval [CI]: 0.38-0.95). A total of 35 studies were included in the subsequent meta-analysis. Comparing 1,056 participants with DR to 920 controls, the pooled weighted mean difference (WMD) of vitamin C was -11.01 (95% CI: -19.35 to -2.67). Regarding vitamins D and E, the pooled WMD was -3.06 (95% CI: -5.15 to -0.96) and -3.03 (95% CI: -4.24 to -1.82), respectively. No associations were identified between DR and circulating vitamin A or carotenoids.
Conclusions:
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.
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