Association of serum 25-hydroxyvitamin D with cataract: a cross-sectional and longitudinal analysis of the UK Biobank.

Background: The association between vitamin D deficiency and cataract is debated, with limited longitudinal data on serum 25-hydroxyvitamin D (25(OH)D) levels in cataract development. This study aimed to examine both cross-sectional and longitudinal associations between serum 25(OH)D concentrations and cataract risk.

Methods: The cross-sectional analyses included 442 255 UK Biobank participants with available serum 25(OH)D data. For longitudinal analyses, 427 923 participants without baseline cataract were assessed. Logistic regression models and Cox proportional hazards models were conducted to evaluate the associations between serum 25(OH)D concentrations and cataract risk.

Results: In the cross-sectional analyses, higher serum 25(OH)D quartiles were inversely associated with cataract risk (p for trend <0.001). Longitudinal analyses, with a mean follow-up of 10.8 years, showed significant associations between vitamin D deficiency and increased incident cataract risk (HR 1.11, 95% CI 1.07 to 1.15). Compared with the reference group (50-75 nmol/L), participants with severe vitamin D deficiency (<25 nmol/L) had a 27% (HR 1.27, 95% CI 1.07 to 1.49), 12% (HR 1.12, 95% CI 1.04 to 1.21) and 9% (HR 1.09, 95% CI 1.04 to 1.14) higher risk of developing cataract among individuals below 50, 50-60 and above 60 years, respectively.

Conclusions: The study identified significant cross-sectional and prospective associations between vitamin D deficiency and increased cataract risk, with younger individuals being more susceptible. These findings emphasise the importance of early monitoring and intervention to address vitamin D deficiency and mitigate cataract risk.