title: Season and ethnicity are determinants of serum 25-hydroxyvitamin D concentrations in New Zealand children aged 5-14 y.
abstract: New Zealand children, particularly those of Māori and Pacific ethnicity, may be at risk for low vitamin D status because of low vitamin D intakes, the country's latitude (35-46 degrees S), and skin color. The aim of this study was to determine 25-hydroxyvitamin D concentrations and their determinants in a national sample of New Zealand children aged 5-14 y. The 2002 National Children's Nutrition Survey was designed to survey New Zealand children, including oversampling of Māori and Pacific children to allow ethnic-specific analyses. A 2-stage recruitment process occurred using a random selection of schools, and children within each school. Serum 25-hydroxyvitamin D concentration [mean (99% CI) nmol/L] in Māori children (n = 456) was 43 (38,49), in Pacific (n = 646) 36 (31,42), and in New Zealand European and Others (NZEO) (n = 483) 53 (47,59). Among Māori, Pacific, and NZEO, the prevalence (%, 99% CI) of serum 25-hydroxyvitamin D deficiency (<17.5 nmol/L) was 5 (2,12), 8 (5,14), and 3 (1,7), respectively. The prevalence of insufficiency (<37.5 nmol/L) was 41 (29,53), 59 (42,75), and 25 (15,35), respectively. Multiple regression analysis found that 25-hydroxyvitamin D concentrations were lower in winter than summer [adjusted mean difference (99% CI) nmol/L; 15 (8,22)], lower in girls than boys [5 (1,10)], and lower in obese children than in those of "normal" weight [6 (1,11)]. Relative to NZEO, 25-hydroxyvitamin D concentrations were lower in Māori [9 (3,15)] and Pacific children [16 (10,22)]. Ethnicity and season are major determinants of serum 25-hydroxyvitamin D. There is a high prevalence of vitamin D insufficiency in New Zealand children, which may or may not contribute to increased risk of osteoporosis and other chronic disease. There is a pressing need for more convincing evidence concerning the health risks associated with the low vitamin D status in New Zealand children.
authors.affiliation: Department of Human Nutrition, Preventive and Social Medicine, University of Otago, Dunedin, New Zealand.
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Rockell
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Green
authors.forename: C Murray
authors.initials: CM
authors.lastname: Skeaff
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Whiting
authors.forename: Rachael W
authors.initials: RW
authors.lastname: Taylor
authors.forename: Sheila M
authors.initials: SM
authors.lastname: Williams
authors.forename: Winsome R
authors.initials: WR
authors.lastname: Parnell
authors.forename: Robert
authors.initials: R
authors.lastname: Scragg
authors.forename: Noela
authors.initials: N
authors.lastname: Wilson
authors.forename: David
authors.initials: D
authors.lastname: Schaaf
authors.forename: Eljon D
authors.initials: ED
authors.lastname: Fitzgerald
authors.forename: Mark W
authors.initials: MW
authors.lastname: Wohlers
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005006:Ethnicity; D005060:Europe / Q000208:ethnology; D005260:Female; D006801:Humans; D008297:Male; D009520:New Zealand / Q000453:epidemiology; D009765:Obesity / Q000097:blood; D010139:Pacific Islands / Q000208:ethnology; D012044:Regression Analysis; D012621:Seasons; D012880:Skin Pigmentation; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D