title: Discrepant association of serum C-3 epimer of 25-hydroxyvitamin D versus non-epimeric 25-hydroxyvitamin D with serum lipid levels.
abstract: 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.
  
  
  METHODS
  This study used data from 1068 randomly selected volunteers in the Thai 4(th) 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.
authors.affiliation: Department of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, 10400, Thailand. laor.cha@mahidol.ac.th.|Division of Endocrinology and Metabolism, Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Rama 6th Road, Bangkok, 10400, Thailand. laor.cha@mahidol.ac.th.
authors.forename: La-Or
authors.initials: LO
authors.lastname: Chailurkit
authors.affiliation: Department of Community Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, 10400, Thailand.
authors.forename: Wichai
authors.initials: W
authors.lastname: Aekplakorn
authors.affiliation: Department of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, 10400, Thailand.
authors.forename: Kriangsuk
authors.initials: K
authors.lastname: Srijaruskul
authors.affiliation: Department of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, 10400, Thailand.
authors.forename: Boonsong
authors.initials: B
authors.lastname: Ongphiphadhanakul
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D008078:Cholesterol, LDL / Q000097:blood; D050171:Dyslipidemias / Q000097:blood* / Q000453:epidemiology / Q000473:pathology; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000453:epidemiology / Q000473:pathology; D016014:Linear Models; D008055:Lipids / Q000097:blood*; D008297:Male; D008875:Middle Aged; D014280:Triglycerides / Q000097:blood; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D008078:Cholesterol, LDL; D008055:Lipids; D014280:Triglycerides; D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: Epimer; Serum lipids; Vitamin D