Vitamin D is essential for healthy bone formation during childhood; sources of vitamin D include natural synthesis as a result of skin exposure to sunlight, and limited food sources that include fortified cereals and oily fish.
Brian Wharton from the Institute of Child Health, London, and Nick Bishop from the University of Sheffield, UK, outline three main reasons which are contributing to an increase in vitamin D deficiency and rickets: the promotion of exclusive breastfeeding for long periods without vitamin D supplementation, particularly for babies whose mothers are vitamin D deficient; reduced opportunities for production of the vitamin in the skin because of female modesty and fear of skin cancer; and the high prevalence of rickets in immigrant groups in more temperate regions.
Nick Bishop comments: "A safety net of extra dietary vitamin D should be re-emphasised, not only for children but also for pregnant women. The reason why many immigrant children in temperate zones have vitamin D deficiency is unclear. We speculate that in addition to differences in genetic factors, sun exposure, and skin pigmentation, iron deficiency may affect vitamin D handling in the skin or gut or its intermediary metabolism."