Vitamin D deficiency in early childhood: prevalent in the sunny South Pacific

Abstract

AbstractObjectiveTo estimate the prevalence of and risk factors for vitamin D deficiency in young urban children in Auckland, New Zealand, where there is no routine vitamin D supplementation.DesignA random sample of urban children. Vitamin D deficiency was defined as serum 25-hydroxyvitamin D <27·5 nmol/l (<11 ng/ml). Logistic regression analysis was used to calculate odds ratios and, from these, relative risks (RR) and 95 % confidence intervals were estimated.SettingAuckland, New Zealand (36°52′S), where the daily vitamin D production by solar irradiation varies between summer and winter at least 10-fold.SubjectsChildren aged 6 to 23 months enrolled from 1999 to 2002.ResultsVitamin D deficiency was present in forty-six of 353 (10 %; 95 % CI 7, 13 %). In a multivariate model there was an increased risk of vitamin D deficiency associated with measurement in winter or spring (RR = 7·24, 95 % CI 1·55, 23·58), Pacific ethnicity (RR = 7·60, 95 % CI 1·80, 20·11), not receiving any infant or follow-on formula (RR = 5·69, 95 % CI 2·66, 10·16), not currently receiving vitamin supplements (RR = 5·32, 95 % CI 2·04, 11·85) and living in a more crowded household (RR = 2·36, 95 % CI 1·04, 4·88).ConclusionsVitamin D deficiency is prevalent in early childhood in New Zealand. Prevalence varies with season and ethnicity. Dietary factors are important determinants of vitamin D status in this age group. Vitamin D supplementation should be considered as part of New Zealand’s child health policy.