Discrepancy between the Recommended and Functional Cut Offs of Vitamin D among Under-five Children: Experiences from a Pilot Study

BACKGROUND AND OBJECTIVES: Vitamin D is a key determinant of bone health and calcium homeostasis in children. Vitamin D deficiency (VDD) in early years may have an effect on total bone mass and risk of osteoporosis. Despite widespread prevalence of VDD among children, there is limited information in under-five age group. The objectives of the current study were to estimate the community-based prevalence of VDD and to identify the factors associated with children aged 1–5 years. MATERIALS AND METHODS: A community-based cross-sectional study was conducted among 201 apparently healthy children (aged 1–5 years) in an urban slum of the selected geographical area in Mumbai. VDD was defined as serum 25-hydroxy Vitamin D (25[OH]D) levels <20 ng/ml as per the US Endocrine society classification. RESULTS: The prevalence of VDD was found to be 74.6% (95% of confidence interval [68.6–80.6]). It was significantly higher (P = 0.04) among children staying indoors (44.8%). 25(OH)D was negatively correlated with parathyroid hormone (PTH) ([r = −0.199, P = 0.005]) and Alkaline phosphatase ([r = −0.140, P = 0.05]). However, the increase in PTH was observed when 25(OH)D levels were <10 ng/ml unlike anticipated increase at <20 ng/ml. CONCLUSION: The study revealed a high prevalence of VDD in 1–5 years age group. It was observed that the outdoor activities and sun exposure have a significant association with Vitamin D status. Majority of children had normal PTH levels despite VDD. The study endorses the importance of sun exposure and throws light on that fact that functional cutoffs for VDD may be lower in under-five children and also highlights the need of redefining cutoffs of Vitamin D among the Indian children.