Severe vitamin D deficiency is a risk factor for renal hyperfiltration

Background: Vitamin D deficiency is associated with renal progression in chronic kidney disease. Moreover, improvement of clinical outcomes after vitamin D supplementation has been reported in the diabetic and chronic kidney disease population. Objective: We investigated the association between renal hyperfiltration (RHF) and vitamin D status in a relatively healthy population. Design: Data were retrieved from the Korean NHANES, a nationwide population-based cross-sectional study from 2008 to 2015. Overall, 33,210 subjects with normal renal function were included in the final analysis. Severe vitamin D deficiency was defined as serum 25-hydroxyvitamin D concentration <10 ng/mL. RHF was defined as estimated glomerular filtration rate with residual in the >95th percentile after adjustment for age, sex, height, weight, and history of hypertension or diabetes. Results: The mean +/- SD age of subjects was 48.1 +/- 15.9 y, and the number of women was 18,779 (56.5%). Estimated glomerular filtration rate was negatively associated with serum 25-hydroxyvitamin D concentrations in multivariable linear regression analysis (beta: -0.02; 95% CI: -0.02, -0.01; P < 0.001). Furthermore, 1637 (4.9%) subjects were categorized into the RHF group, and the prevalence of RHF was significantly higher in the severe vitamin D deficiency group than in the sufficiency group (5.8% compared with 5.0%, P < 0.001). In a multivariable logistic regression model, severe vitamin D deficiency was a significant risk factor for RHF (OR: 2.41; 95% CI, 1.72, 3.43; P < 0.001). Conclusions: Severe vitamin D deficiency is significantly associated with increasing prevalence of RHF in a relatively healthy adult population.