title: Vitamin D is associated with testosterone and hypogonadism in Chinese men: Results from a cross-sectional SPECT-China study.
abstract: BACKGROUND
  To date, no study has explored the association between androgen levels and 25-hydroxyvitamin D (25(OH)D) levels in Chinese men. We aimed to investigate the relationship between 25(OH)D levels and total and free testosterone (T), sex hormone binding globulin (SHBG), estradiol, and hypogonadism in Chinese men.
  
  
  METHODS
  Our data, which were based on the population, were collected from 16 sites in East China. There were 2,854 men enrolled in the study, with a mean (SD) age of 53.0 (13.5) years. Hypogonadism was defined as total T <11.3 nmol/L or free T <22.56 pmol/L. The 25(OH)D, follicle-stimulating hormone, luteinizing hormone, total T, estradiol and SHBG were measured using chemiluminescence and free T by enzyme-linked immune-sorbent assay. The associations between 25(OH)D and reproductive hormones and hypogonadism were analyzed using linear regression and binary logistic regression analyses, respectively.
  
  
  RESULTS
  A total of 713 (25.0 %) men had hypogonadism with significantly lower 25(OH)D levels but greater BMI and HOMA-IR. Using linear regression, after fully adjusting for age, residence area, economic status, smoking, BMI, HOMA-IR, diabetes and systolic pressure, 25(OH)D was associated with total T and estradiol (P < 0.05). In the logistic regression analyses, increased quartiles of 25(OH)D were associated with significantly decreased odds ratios of hypogonadism (P for trend <0.01). This association, which was considerably attenuated by BMI and HOMA-IR, persisted in the fully adjusted model (P for trend <0.01) in which for the lowest compared with the highest quartile of 25(OH)D, the odds ratio of hypogonadism was 1.50 (95 % CI, 1.14, 1.97).
  
  
  CONCLUSIONS
  A lower vitamin D level was associated with a higher prevalence of hypogonadism in Chinese men. This association might, in part, be explained by adiposity and insulin resistance and warrants additional investigation.
authors.affiliation: Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China. wnj486@126.com.
authors.forename: Ningjian
authors.initials: N
authors.lastname: Wang
authors.affiliation: Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China. foxhb1423@126.com.
authors.forename: Bing
authors.initials: B
authors.lastname: Han
authors.affiliation: Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China. liqin20001@163.com.
authors.forename: Qin
authors.initials: Q
authors.lastname: Li
authors.affiliation: Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China. chenyi9h@126.com.
authors.forename: Yi
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China. ccyanzhi@126.com.
authors.forename: Yingchao
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China. xiafangzhen@126.com.
authors.forename: Fangzhen
authors.initials: F
authors.lastname: Xia
authors.affiliation: Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China. lindongping2005@126.com.
authors.forename: Dongping
authors.initials: D
authors.lastname: Lin
authors.affiliation: Endocrine Research Unit, Mayo Clinic, Rochester, MN, 55905, USA. jensen@mayo.edu.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Jensen
authors.affiliation: Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China. luyingli2008@126.com.
authors.forename: Yingli
authors.initials: Y
authors.lastname: Lu
mesh_terms: D000328:Adult; D000368:Aged; D002681:China; D003430:Cross-Sectional Studies; D004958:Estradiol / Q000097:blood; D006801:Humans; D007006:Hypogonadism / Q000097:blood* / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D013739:Testosterone / Q000097:blood*; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D012738:Sex Hormone-Binding Globulin; D014807:Vitamin D; D013739:Testosterone; D004958:Estradiol; C104450:25-hydroxyvitamin D