The prevalence of vitamin D deficiency in children in the Northern Territory

Aims: The primary aim of this study was to determine the frequency of vitD deficiency/insufficiency in an opportunistic sample of Northern Territory (NT) children. The secondary aim was to evaluate whether: (i) 25(OH)vitD (25(OH)D) levels differ between Indigenous/non-Indigenous children; and (ii) VitD insufficiency is associated with increased acute/infective hospitalisations.

Methods: Twenty-five (OH)D levels were measured in 98 children <16 years between August 2011 and January 2012 (children hospitalised acutely/non-acutely and well children from other studies based in Darwin). VitD deficiency was defined as 25(OH)D < 50 nmol/L, and insufficiency was postulated to be <75 nmol/L. Demographic data were collected, and computer records were reviewed.

Results: Median age was 59 months (range 2–161); 3.1% were vitD deficient, 19.4% insufficient. There was no significant difference in mean 25(OH)D level between Indigenous (93.2, standard deviation (SD) 21.9, n = 42) and non-Indigenous (97.3, SD 27.9, n = 56) children (P = 0.32). Median number of hospitalisations/year were similar (P = 0.319) between vitD sufficient (0.34, range 0–12, n = 76) and insufficient (0.22, 0–6, n = 22) children. There was no significant difference between number of infective admissions per year between vitD sufficient/insufficient groups (P = 0.119).

Conclusions: Compared with US data (19% deficient, 65% insufficient) fewer NT children are vitD deficient/insufficient. In our limited sample, being vitD insufficient was not associated with increased acute/infective hospitalisations, but a larger unbiased sample of NT children is needed. More information is needed about the optimum level of vitD for non-bone-related health in children.