title: Serum 25-hydroxyvitamin D concentrations of New Zealanders aged 15 years and older.
abstract: BACKGROUND
  Vitamin D plays an important role in bone health. Our purpose was to measure serum 25-hydroxyvitamin D concentrations and their determinants in a national sample (n=2,946) of New Zealanders aged 15 years and over.
  
  
  RESULTS
  Mean (99% CI) serum 25-hydroxyvitamin D concentrations were 47 (45-50) nmol/l in women and 52 (49-55) nmol/l in men. Mean concentrations in New Zealand European and Others (NZEO, n=2,440), Māori (n=370), and Pacific (n=136) were 51 (49-53), 42 (38-46) and 37 (33-42) nmol/l, respectively. Three percent of New Zealanders had serum 25-hydroxyvitamin D concentrations indicative of deficiency (<or=17.5 nmol/l); 48% and 84% were insufficient based on cutoffs of <or=50 and <or=80 nmol/l. Determinants of serum 25-hydroxyvitamin D concentrations in women were age, ethnicity, obesity, latitude and season; determinants in men were ethnicity and season. Serum 25-hydroxyvitamin D in women declined with age; mean concentration was 13 (8-18) nmol/l lower in women 65 years or older and 9 (5-13) nmol/l lower in women 45-64 years compared with women 15-18 years. Spring to summer differences in serum 25-hydroxyvitamin D were 31 (28-34) and 28 (25-31) nmol/l in women and men, respectively. Obese women had lower vitamin status than normal-weight women by 6 (3-10). Women living in the South Island had a mean serum 25-hydroxyvitamin D that was 6 (3-9) nmol/l lower than women living in the North Island. Ethnicity and season are the major determinants of serum 25-hydroxyvitamin D in New Zealanders.
  
  
  CONCLUSIONS
  The high prevalence of vitamin D insufficiency in New Zealanders, particularly in older women, may warrant strategies to improve vitamin D status.
authors.affiliation: Department of Human Nutrition, University of Otago, P.O. Box 56, Dunedin, New Zealand.
authors.forename: J E P
authors.initials: JE
authors.lastname: Rockell
authors.forename: C M
authors.initials: CM
authors.lastname: Skeaff
authors.forename: S M
authors.initials: SM
authors.lastname: Williams
authors.forename: T J
authors.initials: TJ
authors.lastname: Green
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000097:blood; D015992:Body Mass Index; D005006:Ethnicity / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D009749:Nutrition Surveys; D015995:Prevalence; D012016:Reference Values; D012621:Seasons; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000453:epidemiology
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D