Author: André Ferreira (Portugal)
Co-authors: Nisa Silva, Maria João Furtado, Angela Carneiro, Miguel Lume, José Paulo Andrade
Purpose
Age-related macular degeneration (AMD) is the leading cause of blindness in the industrialized countries and the third worldwide after glaucoma and cataract, according to the World Health Organization. Vitamin D may be implicated in the pathophysiology of several ocular diseases, but its role in age-related macular degeneration (AMD) remains uncertain. We sought to review systematically the existing evidence to evaluate the association between serum 25-hydroxyvitamin D 25(OH)D levels and AMD.
Setting/Venue
Systematic review of observational studies with meta-analysis.
Methods
A four-database search (Pubmed, ISI Web of Science, Cochrane, and Scopus) was performed from inception to May 2020 using the MeSH terms: (“Macular Degeneration” OR “Age-related macular degeneration” OR “Retinal degeneration” OR “Macula lutea”) AND (“Vitamin D” OR “Ergocalciferols” OR “Cholecalciferol” OR “25-Hydroxyvitamin D”). Random-effects meta-analysis were performed to compute 1) the standard mean difference in 25(OH)D concentration between AMD and non-AMD patients and 2) the AMD risk according to serum 25(OH)D levels.
Results
Eighteen observational studies enrolling 75,294 patients after a selection process among 375 original abstracts were selected. This review included 11 cross-sectional studies, 4 case-control, 2 cohorts and 1 case series. A total of 75,294 adults were recruited, 9,736 of which presenting AMD. The number of participants ranged from 30 to 17,045, with a range of 15–2359 AMD cases. Both middle-aged and elderly participants were recruited. In the first meta-analysis, the summary standard means difference of −0.13 (95%CI: −0.35; 0.08) indicates a non-significant difference of -13% between the average members of the AMD and the non-AMD groups (P = 0.26). In the second meta-analysis, no significant differences were found, but there appears to exist a trend for late AMD among subjects with serum 25(OH)D below 50 nmol/L (OR 1.8, 95%CI: 1.00–3.24, P = 0.05).
Conlusions
There is no clear evidence of an inverse association between serum 25(OH)D and AMD risk, mainly due to heterogeneity in studies procedures and lack of longitudinal designs. Further longitudinal studies are needed, ideally taking both genetic and environmental factors into account, to clarify the role of serum vitamin D on AMD pathophysiology. If an association between vitamin D deficiency and AMD is proven, this might influence further supplementation strategies that, so far, do not include vitamin D.
Financial Disclosure
None
Comments
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