Serum selenium concentrations and dietary selenium intake of New Zealand children aged 5-14 years.

Serum Se concentrations and dietary Se intakes have been determined in relation to age, sex, ethnicity, region and index of deprivation in a nationally representative sample of New Zealand children aged 5-14 years from the 2002 National Children's Nutrition Survey. Dietary intake was assessed from computer-assisted, multiple-pass 24 h diet recall interviews (n 3275). Serum Se concentrations were obtained from a subset of urban-based children (n 1547). Mean (95 % CI) serum Se concentration in children was 0.96 (0.93, 1.00) micromol/l. Males (1.00 micromol/l) had higher serum Se levels than females (0.93 micromol/l; P = 0.027). Mäori children had lower serum Se than Pacific Islands children (P = 0.038) and New Zealand European and Other children (P = 0.005). Children in the Upper North Island (1.06 micromol/l) had higher mean serum Se values than those in the Lower North Island (0.98 micromol/l, P < 0.0005) and South Island (0.79 micromol/l, P < 0.0005), and serum Se in the Lower North Island was higher than that in the South Island (P < 0.0005). Mean dietary Se intake was 36 (34, 37) microg/d. The intakes of children aged 5-6 years (31 microg/d) were lower than those of children aged 7-10 and 11-14 years (35 and 38 microg/d, respectively; P < 0.00 005) and the intakes of 7-10-year-olds were lower than those of 11-14-year-olds (P = 0.002). Serum Se was associated with dietary Se after adjusting for all variables, including region (P = 0.006). The Se status of our children falls in the middle of the international range of serum Se concentrations, but that for children in the South Island is among the lowest values reported and may be a cause for concern.

Season and ethnicity are determinants of serum 25-hydroxyvitamin D concentrations in New Zealand children aged 5-14 y.

New Zealand children, particularly those of Maori 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 Maori 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 Maori 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 Maori, 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 Maori [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.