Grant: Operating Grant - Priority Announcement: INMD Start Up Funds (bridge funding)

Vitamin D can be made in the skin by exposure to sunlight and can be found in certain foods. Vitamin D levels are alarmingly low in many North American children. Several health issues have been linked with low vitamin D. These include colds caused by viruses and asthma attacks. However, no study has determined whether vitamin D supplementation can reduce the risk of these conditions in young children where they are most common and most severe. The goals of this study are to determine whether wintertime vitamin D supplementation of preschoolers can prevent colds and asthma attacks and find out what dose of vitamin D supplement works best. We also aim to work out how much money would be saved by the health care system and society if preschoolers were routinely supplemented with Vitamin D during the winter. We believe that the higher the dose of vitamin D, the less likely a child will have colds, asthma attacks, and low vitamin D levels and the less they will use the medical system and keep their parents away from work. Exposure to sunlight to make vitamin D is limited for much of the year in Canada. Therefore, understanding how much vitamin D should be taken by young children to decrease common child health issues like colds is of critical importance and may offer a significant reduction in suffering and associated economic costs. This information would be very important to parents, doctors and policy makers.