Understanding the role of vitamin D—which regulates inflammatory responses—in noninfectious uveitis (an inflammatory disease) may provide insight into treatment and prevention of this disease.Objective
To investigate whether there is an association between hypovitaminosis D and incident noninfectious uveitis.Design, Setting, and Participants
In a retrospective case-control study, data from a health care claims database containing deidentified medical claims from a large private insurer were used to identify 558 adults enrolled from January 1, 2000, to December 31, 2016, who received a diagnosis of noninfectious uveitis from an eye care clinician (with receipt of a confirmatory diagnosis within 120 days of the initial diagnosis) and who had a vitamin D level measured within 1 year before the first diagnosis. Exclusion criteria included having systemic disease or receiving medication known to lower vitamin D levels, having undergone intraocular surgery, and having infectious uveitis. Each case patient was matched with 5 controls on the basis of age, sex, race/ethnicity, and index date (2790 controls). The controls had vitamin D level determined either within 1 year before or within 6 months after receiving an eye examination with normal findings. Multiple logistic regression models were used to examine the association between hypovitaminosis D and noninfectious uveitis.Main Outcomes and Measures
The primary, prespecified analysis assessed the association of noninfectious uveitis with hypovitaminosis D (vitamin D level ≤20 ng/mL).Results
The 558 cases and 2790 controls were matched on age, and each group had a mean (SD) age of 58.9 (14.7) years. Among the cohort of 3348 patients, 2526 (75.4%) were female, and the racial/ethnic distribution in the matched samples was 2022 (60.4%) white, 552 (16.5%) black, 402 (12.0%) Hispanic, 162 (4.8%) Asian, and 210 (6.3%) unknown. Patients with normal vitamin D levels had 21% lower odds of having noninfectious uveitis than patients with low vitamin D levels (odds ratio [OR], 0.79; 95% CI, 0.62-0.99; P = .04). In a race-stratified analysis, an association between vitamin D and uveitis was found in black patients (OR, 0.49; 95% CI, 0.30-0.80; P = .004) and was qualitatively similar but nonsignificant in white patients (OR, 0.87; 95% CI, 0.62-1.21; P = .40) and Hispanic patients (OR, 0.60; 95% CI, 0.33-1.10; P = .10).Conclusions and Relevance
This and other reports have found an association between hypovitaminosis D and noninfectious uveitis. However, these studies cannot establish a causal relationship. Prospective studies are warranted to evaluate whether hypovitaminosis D causes increased risk of uveitis and the role of vitamin D supplementation in prevention and treatment of uveitis.