Discrepant association of serum C-3 epimer of 25-hydroxyvitamin D versus non-epimeric 25-hydroxyvitamin D with serum lipid levels

Abstract

© 2016 The Author(s). Background: Low vitamin D status has been associated with a number of chronic diseases. For dyslipidemia, vitamin D deficiency has been associated with higher low density lipoprotein-cholesterol (LDL-C) in a number of studies, but with inconsistent results in clinical trials.  The purpose of the present study is to explore the relative importance of 3-epi-25-hydroxyvitamin D (25(OH)D) as compared with the non-epimeric form in relation to serum lipid. Method: This study used data from 1068 randomly selected volunteers in the Thai 4th National Health Examination Survey (NHES IV). Serum 25(OH)D2, 25(OH)D3, 3-epi-25(OH)D2 and 3-epi-25(OH)D3 were analyzed by liquid chromatography-tandem mass spectrometry. Results: There was no association between serum total 25(OH)D and serum LDL-C. However, circulating 3-epi-25(OH)D3 was negatively related to serum LDL-C (r = -0.077, P <0.05), while no such association was found for non-epimeric 25(OH)D3 (r =0.030, P = 0.33). On the other hand, both 3-epi-25(OH)D3 (r = 0.175, P <0.001) and non-epimeric 25(OH)D3 (r = 0.142, P <0.001) were positively related to serum triglyceride (TRIG) levels. In multiple linear regression models with age, gender, body mass index, urban residence, education, hypertension and education as covariates, it was found that 3-epi-25(OH)D3 was independently associated with serum LDL-C (beta = -0.12, P <0.01), while non-epimeric 25(OH)D3 was positively related to LDL-C (beta = 0.13, P = 0.002). For TRIG, there were positive association with 3-epi-25(OH)D3 (beta = 0.27, P <0.001) and negative association with non-epimeric 25(OH)D3 (beta = - 0.10, P = 0.011) independent of age, gender, urban resident and education. Conclusions: There is a discrepant association of 25(OH)D levels with serum lipids according to 25(OH)D epimeric forms.