Grant: Operating Grant

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 'high dose' vitamin D supplementation of preschoolers can prevent colds and asthma attacks. 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 preschoolers receiving 'high dose' vitamin D supplementation during the wintertime will be less likely to have colds, asthma attacks, and low vitamin D levels and will be less likely to 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 whether vitamin D supplementation can decrease common child health issues like colds and asthma attacks is of critical importance and may offer a large reduction in suffering and economic costs. This information would be very important to parents, doctors, employers and policy makers.