Grant: Operating Grant

Because of Canada's northern latitude, understanding vitamin D deficiency and associated preventable health problems is of major importance to Canadian children and their parents. There is reason for concern that low vitamin D levels may be contributing to the development of some of the commonest health issues affecting Canadian children including fractures, asthma, respiratory infections, obesity and high blood pressure. With previous support from CIHR, we have developed an innovative and powerful pediatric primary care practice based research network called TARGet Kids! to conduct studies on the nutritional health of Canada's young children. Using TARGet Kids!, we have recruited 2000 children between 1 and 5 years of age with detailed clinical and laboratory measurements including vitamin D level. Early results are suggesting that up to eighty percent of these young children have insufficient vitamin D levels. In this proposed longitudinal cohort study, we will follow children for 4 years during their regularly schedule primary healthcare visits to determine whether their vitamin D level increases their risk of developing asthma, respiratory infections, obesity or high blood pressure. Collectively, fractures, asthma and respiratory infections make up one third of all emergency department visits for children in Ontario and obesity alone costs Canada's health care system 1.8 billion dollars annually. If low vitamin D level is contributing to the development of any of these health conditions, measures to increase vitamin D levels may offer a significant benefit in reducing population wide illness and associated short-term and long-term healthcare costs. This study will launch Canada as a leader in childhood vitamin D research. Information from this study will assist parents, clinicians and policy makers in determining practice recommendations and health policy related to vitamin D supplementation and health policy for Canadian children.