The Short-Term Effects of Vitamin D Repletion on Cholesterol

Abstract

Objective— Vitamin D deficiency is common and associated with dyslipidemia. However, it is unclear whether oral vitamin D supplementation improves the lipid profile. Therefore, we conducted a randomized, placebo-controlled trial to determine the short-term effects of vitamin D repletion on the lipid profile. Methods and Results— One hundred fifty-one vitamin D−deficient (25-hydroxyvitamin D <20 ng/mL) adults with elevated risk for cardiovascular disease were randomized to receive either 50 000 IU of vitamin D3 weekly for 8 weeks or placebo. The primary outcome was the change in small low-density lipoprotein (LDL) particle number. Secondary outcomes included changes in other n uclear magnetic resonance −based and chemical lipid fractions. Vitamin D failed to improve the lipid profile. Compared with the placebo, vitamin D repletion did not change small LDL particle number (mean change, +18 nmol/L; 95% CI [−80 to +116 nmol/L]; P =0.63). There were also no changes in the chemical lipid profile: total cholesterol (+5.8 mg/dL, 95% CI [−1.4 to +13.0 mg/dL], P =0.14); LDL cholesterol (+3.8 mg/dL, 95% CI [−2.5 to +10.2 mg/dL], P =0.13); high–density lipoprotein cholesterol (+0.4 mg/dL 95% CI [−1.6 to +2.6 mg/dL], P =0.71); and triglycerides (+7.9 mg/dL 95% CI [−6.5 to +22.3 mg/dL]). In the vitamin D repletion group, exploratory multivariate regression analysis demonstrates that changes in LDL cholesterol were positively correlated with the changes in serum calcium ( P <0.001) and inversely with the changes in serum parathyroid hormone ( P =0.02). Conclusion— In contrast to the association between low 25-hydroxyvitamin D levels and dyslipidemia, correcting vitamin D deficiency in the short-term does not improve the lipid profile. Repletion of 25-hydroxyvitamin D levels raised serum calcium levels and decreased serum parathyroid hormone levels. These expected physiological responses to vitamin D therapy were correlated with a significant increase in LDL cholesterol. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT01008384.