beyond reason
https://onlinelibrary.wiley.com/doi/pdf/10.1111/aos.12688


ABSTRACT.
Whether vitamin C is a protective factor for age-related cataract remains
unclear. Thus, we conducted a meta-analysis to summarize the evidence from
epidemiological studies of vitamin C and the risk of age-related cataract.
Pertinent studies were identified by searching in PubMed and in Webscience.
The random effect model was used to combine the results. Meta-regression and
subgroups analyses were used to explore potential sources of between-study
heterogeneity. Publication bias was estimated using Egger’s regression asym-
metry test. Finally, 15 articles with 20 studies for vitamin C intake and eight
articles with 10 studies for serum ascorbate were included in this meta-analysis.
The relative risk (RR) and 95% confidence interval of cataract for the highest
versus the lowest category of vitamin C intake was 0.814 (0.707–0.938), and the
associations were significant in America and Asia. Significant association of
cataract risk with highest versus the lowest category of serum ascorbate was
found in general [0.704 (0.564–0.879)]. Inverse associations were also found
between serum ascorbate and nuclear cataract and posterior subcapsular
cataract. Higher vitamin C intake and serum ascorbate might be inversely
associated with risk of cataract. Vitamin C intake should be advocated for the
primary prevention of cataract.