Vitamin D status of Canadians employed in northern latitudes

Background Vitamin D deficiency and insufficiency are prevalent worldwide, but relatively few studies have examined vitamin D status in working populations. Aims To assess the prevalence of vitamin D deficiency and insufficiency in Canadian workers and investigate risk factors in this population. Methods A cross-sectional study using data from a health programme enrolling workers mostly from Northern Alberta, Canada. As part of the programme, volunteers were invited to complete a lifestyle questionnaire. Blood was taken to determine plasma 25-hydroxyvitamin D (25(OH)D) levels. Logistic and linear regressions were used to investigate the relationships between individual characteristics and vitamin D status. Results Between October 2007 and December 2012, 6101 eligible workers enrolled in the health programme. The prevalence of vitamin D deficiency (plasma 25(OH) D, levels <27.5 nmol/l) and insufficiency (<37.5 nmol/l) were 3 and 8%, respectively. Male employees were significantly more likely to be vitamin D deficient and insufficient than females. Residing at a more northern latitude increased the likelihood of vitamin D deficiency and insufficiency. Age, assessments made in summer, better general health and physical activity and use of vitamin D supplementation were all related to lower likelihood of deficiency and insufficiency. Conclusions Vitamin D deficiency and insufficiency are a concern in this sample of Canadian workers. Vitamin D supplementation is recommended to reduce the prevalence of deficiency and insufficiency in this group.