title: Relation of Age, Sex and Bone Mineral Density to Serum 25-Hydroxyvitamin D Levels in Chinese Women and Men.
abstract: OBJECTIVE
  To investigate the relation of circulating 25-hydroxyvitamin D (25[OH]D) levels to age, sex, and bone mineral density (BMD) in adults living in Guangzhou Province.
  
  
  METHODS
  This cross-sectional study comprised 188 women and 122 men aged 17-88 years who were randomly sampled among community-dwelling Guangzhou residents. BMD at the lumbar spine and femoral neck was measured by dual energy X-ray absorptiometry, and serum concentrations of 25(OH)D, parathyroid hormone (PTH), procollagen I N-terminal peptide, and beta C-telopeptide of collagen were assayed by electrochemiluminescence immunoassay. Serum 25(OH)D concentrations were divided into four subgroups: severe deficiency (<10 ng/mL), deficiency (10-20 ng/mL), insufficiency (20-30 ng/mL), and sufficiency (≥30 ng/mL).
  
  
  RESULTS
  The mean age of participants was 47.39 ± 19.32 years. Serum 25(OH)D levels were significantly lower in women than men (25.35 ± 6.59 ng/mL vs 27.25 ± 7.94 ng/mL, P < 0.05). The prevalence of 25(OH)D severe deficiency (<10 ng/mL) was 1.6% in men, zero in women; 25(OH)D deficiency (10-20 ng/mL) was 22.9% in women and 20.5% in men; and 25(OH)D insufficiency (20-30 ng/mL) was 73.4% in women and 65.6% in men. An inverse relationship between serum 25(OH)D levels and age (r = -0.249, P < 0.01) was observed in men, but no correlation was found in women (r = 0.130, P > 0.05). Serum 25(OH)D levels were positively associated with lumbar spine and femoral neck BMD (r = 0.382, P < 0.01; r = 0.384, P < 0.01, respectively) in elderly women and (r = 0.332, P < 0.05; r = 0.260, P < 0.05, respectively) and in young men. When adjustments were made for age, correlations between serum 25(OH)D levels and lumbar spine and femoral neck BMD persisted (r = 0.325, P < 0.05; r = 0.323, P < 0.05, respectively) in elderly women. However, age-adjusted serum 25(OH)D levels were positively correlated with BMD at lumbar spine (r = 0.278, P < 0.05) but not at femoral neck (r = 0.165, P > 0.05) in young men. No association between unadjusted or age-adjusted serum 25(OH)D levels and lumbar spine and femoral neck BMD was found in young and middle-aged women and in middle-aged and elderly men. Neither serum PTH levels nor bone turnover markers were related to unadjusted and age-adjusted serum 25(OH)D levels in our participants.
  
  
  CONCLUSIONS
  More than two-third of participants residing in Guangzhou had vitamin D insufficiency. Serum 25(OH)D level is an important biomarker for BMD in elderly women and young men.
authors.affiliation: Department of Orthopaedics Surgery, First Affiliated Hospital of Guangzhou University of Traditional Chinese Medicine, Guangzhou, China.|Key Laboratory of Orthopaedics & Traumatology, Guangzhou University of Traditional Chinese Medicine, Guangzhou, China.
authors.forename: Qiu-shi
authors.initials: QS
authors.lastname: Wei
authors.affiliation: Department of Orthopaedics Surgery, First Affiliated Hospital of Guangzhou University of Traditional Chinese Medicine, Guangzhou, China.|Key Laboratory of Orthopaedics & Traumatology, Guangzhou University of Traditional Chinese Medicine, Guangzhou, China.
authors.forename: Zhen-qiu
authors.initials: ZQ
authors.lastname: Chen
authors.affiliation: Department of Rehabilitation, General Hospital of Guangzhou Military Command of the People's Liberation Army, Guangzhou, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Tan
authors.affiliation: Department of Rehabilitation, General Hospital of Guangzhou Military Command of the People's Liberation Army, Guangzhou, China.
authors.forename: Hai-rong
authors.initials: HR
authors.lastname: Su
authors.affiliation: Department of Rehabilitation, General Hospital of Guangzhou Military Command of the People's Liberation Army, Guangzhou, China.
authors.forename: Xiao-xiang
authors.initials: XX
authors.lastname: Chen
authors.affiliation: Department of Orthopaedics Surgery, First Affiliated Hospital of Guangzhou University of Traditional Chinese Medicine, Guangzhou, China.|Key Laboratory of Orthopaedics & Traumatology, Guangzhou University of Traditional Chinese Medicine, Guangzhou, China.
authors.forename: Wei
authors.initials: W
authors.lastname: He
authors.affiliation: Department of Rehabilitation, General Hospital of Guangzhou Military Command of the People's Liberation Army, Guangzhou, China.
authors.forename: Wei-min
authors.initials: WM
authors.lastname: Deng
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood / Q000502:physiology*; D044466:Asian People / Q000706:statistics & numerical data; D015415:Biomarkers / Q000097:blood; D015519:Bone Density / Q000502:physiology*; D016723:Bone Remodeling / Q000502:physiology; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012727:Sex Characteristics; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology / Q000503:physiopathology; D055815:Young Adult
chemical_list: D015415:Biomarkers; D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: 25 hydroxyvitamin D; Age; Bone mineral density; Bone turnover markers