Associations between Serum 25-hydroxyvitamin D and Lipids, Lipoprotein Cholesterols, and Homocysteine.

Background: Serum 25(OH) vitamin D levels are inversely associated with cardiovascular disease (CVD) mortality, mediated in part by independent positive relationships with high-density lipoprotein cholesterol (HDLC) and inverse relationships with low-density lipoprotein cholesterol (LDLC), triglyceride, and homocysteine.

Aims: In this study, we assessed relationships between fasting serum vitamin D and lipids, lipoprotein cholesterols, and homocysteine.

Materials and methods: We studied 1534 patients sequentially referred to our center from 2007 to 2016. Fasting serum total 25(OH) vitamin D, plasma cholesterol, triglyceride, HDLC, LDLC, and homocysteine were measured. Stepwise regression models were used with total cholesterol, triglyceride, HDLC, LDLC, and homocysteine as dependent variables and explanatory variables age, race, gender, body mass index (BMI), and serum vitamin D levels. Relationships between quintiles of serum vitamin D and triglycerides, HDLC, LDLC, and homocysteine were assessed after covariance adjusting for age, race, gender, and BMI.

Results: Fasting serum vitamin D was positively correlated with age, HDLC, and White race, and was inversely correlated with BMI, total and LDL cholesterol, triglyceride, and fasting serum homocysteine (P ≤ 0.0001 for all). Serum vitamin D was a significant independent inverse explanatory variable for total cholesterol, triglyceride, and LDL cholesterol, and accounted for the largest amount of variance in serum total cholesterol (partial R (2) =3.6%), triglyceride (partial R (2) =3.1%), and LDLC (partial R (2) =2.9%) (P < 0.0001 for all). Serum vitamin D was a significant positive explanatory variable for HDLC (partial R (2) = 1.4%, P < 0.0001), and a significant inverse explanatory variable for homocysteine (partial R (2) = 6.0-12.6%).

Conclusions: In hyperlipidemic patients, serum vitamin D was a significant independent inverse determinant of total cholesterol, LDLC, triglyceride, and homocysteine, and a significant independent positive determinant of HDLC. Thus, serum vitamin D might be protective against CVD.