Persistence of vitamin D-deficiency rickets in Toronto in the 1990s

In 1946, Professor F.F. Tisdall, an eminent nutrition scientist of the time, predicted that childhood vitamin D deficiency would soon no longer be a public health problem.1 His optimism stemmed from the knowledge that vitamin D deficiency rickets could easily be prevented by exposure of the skin to sunlight or by the addition of a small amount of supplemental vitamin D to infant formula. This view has been shared by the medical community and the public, such that in 1966 Harrison described nutritional rickets as a medical curiosity.2 In Canada vitamin D-deficiency rickets appears to be a continuing problem. In 1967 we published a study3 based on 39 infants with vitamin D deficiency seen at The Hospital for Sick Children in Toronto and the Montreal Children's Hospital. The persistence of vitamin D deficiency among native populations in Manitoba communities has been well documented.4,5 Except for one study on vita- min D deficiency among children of vegetarian parents,6 we are not aware of reports describing a large number of vitamin D-deficient children in Canadian cities in recent years. This paper presents evidence that infantile vitamin D deficiency is a persisting problem in Toronto in the 1990s. We also examined the factors that make the children in these cases susceptible to vitamin D deficiency.