A clinician's guide to vitamin D and bone health in children.

Vitamin D and calcium are key determinants of bone health; deficiency in either or both can cause nutritional rickets in children and osteomalacia in children and adults. Vitamin D is essential for absorption and supply of calcium and phosphate for bone mineralisation. Individuals at risk of deficiency in either nutrient can be broadly classed into 2 categories; healthy at-risk population and those with pre-disposition due to underlying chronic health conditions. In the former, vitamin D deficiency (VDD) predominantly results from restricted Ultraviolet B, either due to environmental (high latitude residence), biological (dark skin pigmentation) or behavioural (sun avoidance, covered clothing) factors. Calcium deficiency is predominant in individuals with restricted diet. Only a small fraction of children, during states of high physiological demands such as infancy and adolescence, come to medical attention with symptomatic VDD (hypocalcaemic seizures, dilated cardiomyopathy, tetany) or rickets. The vast majority of at-risk population with osteomalacia (including pregnant women) remain unrecognised due to its non-specific presentation (malaise, tiredness). Clinicians can play an active role in recognising risk groups and optimising bone health through promotion of dietary calcium, vitamin D supplementation at every health care contact and biochemical surveillance in individuals with chronic conditions. Liberal supplementation of at-risk groups is more effective than biochemical testing; however large-scale prevention requires political support to implement robust supplementation and food fortification policies. This article briefly outlines what clinicians need to know about vitamin D and bone health in children and young people. [ABSTRACT FROM AUTHOR]