title: Oral vitamin D supplementation has a lower bioavailability and reduces hypersecretion of parathyroid hormone and insulin resistance in obese Chinese males.
abstract: OBJECTIVE
  To examine the vitamin D status, SNP of the vitamin D receptor gene (VDR) and the effects of vitamin D supplementation on parathyroid hormone and insulin secretion in adult males with obesity or normal weight in a subtropical Chinese city.
  
  
  METHODS
  An intervention trial.
  
  
  METHODS
  Shenzhen City, Guangdong Province, China.
  
  
  METHODS
  From a cross-sectional survey conducted from June to July, eighty-two normal-weight and ninety-nine obese males (18-69 years) were screened to analyse their vitamin D status and for five SNP of VDR. From these individuals, in the same season of a different year, obese and normal-weight male volunteers (twenty-one per group) were included for an intervention trial with oral vitamin D supplementation at 1250 µg/week for 8 weeks.
  
  
  RESULTS
  For the survey, there was no significant difference (P>0·05) in baseline circulating 25-hydroxyvitamin D concentrations or in the percentages of participants in different categories of vitamin D status between the two groups. The VDR SNP, rs3782905, was significantly associated with obesity (P=0·043), but none of the examined SNP were correlated with serum 25-hydroxyvitamin D when adjusted for age, BMI and study group. After vitamin D supplementation, serum 25-hydroxyvitamin D concentration, hypersecretions of parathyroid hormone and insulin, and insulin resistance in the obese were changed beneficially (P<0·05); however, the increase in serum 25-hydroxyvitamin D was less than that of the normal-weight men.
  
  
  CONCLUSIONS
  For obese and normal-weight men of subtropical China, the summer baseline vitamin D status was similar. However, oral vitamin D supplementation revealed a decreased bioavailability of vitamin D in obese men and ameliorated their hypersecretion of parathyroid hormone and insulin resistance.
authors.affiliation: 1Molecular Biology Lab,Shenzhen Center for Chronic Disease Control (SZCCDC),Shenzhen,People's Republic of China.
authors.forename: Ji-Chang
authors.initials: JC
authors.lastname: Zhou
authors.affiliation: 1Molecular Biology Lab,Shenzhen Center for Chronic Disease Control (SZCCDC),Shenzhen,People's Republic of China.
authors.forename: Yu-Mei
authors.initials: YM
authors.lastname: Zhu
authors.affiliation: 1Molecular Biology Lab,Shenzhen Center for Chronic Disease Control (SZCCDC),Shenzhen,People's Republic of China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Chen
authors.affiliation: 1Molecular Biology Lab,Shenzhen Center for Chronic Disease Control (SZCCDC),Shenzhen,People's Republic of China.
authors.forename: Jun-Luan
authors.initials: JL
authors.lastname: Mo
authors.affiliation: 2Health Service Center of Shuiku Community,SZCCDC,Shenzhen,People's Republic of China.
authors.forename: Feng-Zhu
authors.initials: FZ
authors.lastname: Xie
authors.affiliation: 3Outpatient Department,SZCCDC,Shenzhen,People's Republic of China.
authors.forename: Ying-Hong
authors.initials: YH
authors.lastname: Wen
authors.affiliation: 2Health Service Center of Shuiku Community,SZCCDC,Shenzhen,People's Republic of China.
authors.forename: Ping
authors.initials: P
authors.lastname: Guo
authors.affiliation: 4Department of Chronic Disease Prevention,SZCCDC,Shenzhen,People's Republic of China.
authors.forename: Ji
authors.initials: J
authors.lastname: Peng
authors.affiliation: 5Department of Health and Chronic Disease Management,SZCCDC,2021 Buxin Road,Luohu District,Shenzhen 518020,People's Republic of China.
authors.forename: Jian
authors.initials: J
authors.lastname: Xu
authors.affiliation: 3Outpatient Department,SZCCDC,Shenzhen,People's Republic of China.
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.affiliation: 5Department of Health and Chronic Disease Management,SZCCDC,2021 Buxin Road,Luohu District,Shenzhen 518020,People's Republic of China.
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D044466:Asian People; D001682:Biological Availability; D015992:Body Mass Index; D002681:China; D003430:Cross-Sectional Studies; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007333:Insulin Resistance; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood*; D010281:Parathyroid Hormone / Q000097:blood / Q000378:metabolism*; D020641:Polymorphism, Single Nucleotide; D018167:Receptors, Calcitriol / Q000097:blood / Q000235:genetics; D014807:Vitamin D / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics; D055815:Young Adult
chemical_list: D010281:Parathyroid Hormone; D018167:Receptors, Calcitriol; D014807:Vitamin D
keywords: Chinese male; Insulin resistance; Obesity; Parathyroid hormone; Vitamin D