Vitamin D deficiency is associated with community-acquired clostridium difficile infection: a case–control study

BACKGROUND Clostridium difficile infection (CDI) is increasingly recognized as an important community acquired pathogen causing disease (CA-CDI). Vitamin D [25(OH)D] has immune modulatory effects and plays an important role in intestinal immunity. The role of vitamin D in CA-CDI has not been examined previously. METHODS This was a single referral center case-control study. Cases comprised of all patients with CA-CDI who had a serum 25(OH)D measured within 12 months prior to infection. Controls were drawn from patients who had 25(OH)D checked and matched based on age, gender, race and health status. Serum 25(OH)D was stratified as < 15 ng/mL, 15-30 ng/mL or > 30 ng/mL. Regression models adjusting for potential confounders were used to define independent association between vitamin D and CA-CDI. RESULTS We identified 58 matched case-control pairs (66% women; 85% Caucasian). The mean age was 62 years. The mean serum 25(OH)D level was significantly lower in CA-CDI cases compared to controls (28.5 ng/mL vs. 33.8 ng/mL, p = 0.046). Cases had higher rate of antibiotic exposure and more comorbidity. Serum 25(OH)D < 15 ng/mL was associated with an increased risk of CA-CDI on univariate (Odds ratio (OR) 5.10, 95% confidence interval (CI) 1.51 - 17.24) and multivariate analysis (OR 3.84, 95% CI 1.10 - 13.42). Vitamin D levels between 15-30 ng/mL did not modify disease risk. CONCLUSIONS Low serum 25(OH)D < 15 ng/mL was associated with increased risk of CA-CDI. This suggests vitamin D may have a role in determining susceptibility to CA-CDI.