Purpose
Kidney stones are a common and painful condition. Longitudinal prospective studies on the association between intake of vitamin D and risk of incident kidney stones are lacking.
Materials and Methods
We performed a prospective analysis of 193,551 participants of the Health Professionals Follow-up Study (HPFS), Nurses’ Health Study (NHS) I and II. Participants were divided into categories of total (<100, 100–199, 200–399, 400–599, 600–999, ≥1,000 IU/day) and supplemental (none, <400, 400–599, 600–999, ≥1,000 IU/day) vitamin D intake. During a follow-up of 3,316,846 person-years, there were 6,576 incident kidney stone events. Cox proportional hazards regression models were adjusted for age, BMI, comorbidities, use of medications and intake of other nutrients.
Results
After multivariate adjustment, there was no statistically significant association between intake of vitamin D and risk of stones in HPFS (HR for ≥1,000 vs <100 IU/day 1.08, 95% CI 0.80, 1.47, p-value for trend = 0.92) and NHS I (HR 0.99, 95% CI 0.73, 1.35, p-value for trend = 0.70), whereas there was a suggestion of higher risk in NHS II (HR 1.18, 95% CI 0.94, 1.48, p-value for trend = 0.02). Similar results were found for supplemental vitamin D intake.
Conclusions
Vitamin D intake in typical amounts was not statistically associated with risk of kidney stone formation, though higher risk with higher doses than those studied here cannot be excluded.