We determined whether children older than 1 year from non-western immigrant families had lower serum 25-hydroxyvitamin D levels than children from western born families. Children ages 1-6 years were recruited through the TARGet Kids! practice based research network. Univariable analysis revealed that non-western immigrant children had 4 nmol/L lower 25-hydroxyvitamin D (p=0.006; 95% CI:1.4-8.0) and increased odds of 25-hydroxyvitamin D <50 nmol/L (OR 1.9, 95% CI:1.3–2.9). After adjustment for known vitamin D determinants, cow’s milk intake, vitamin D supplements, season and age were significant covariates and current vitamin D supplementation had the strongest confounding effect. In order to use the ethnicity variable, we developed a new standardized geographically based closed-ended ethnicity question, which was a practical alternative to the widely used open-ended ethnicity questions. There was an association between non-western immigration and lower 25-hydroxyvitamin D in early childhood and this appears primarily related to known vitamin D determinants.

We determined whether children older than 1 year from non-western immigrant families had lower serum 25-hydroxyvitamin D levels than children from western born families. Children ages 1-6 years were recruited through the TARGet Kids! practice based research network. Univariable analysis revealed that non-western immigrant children had 4 nmol/L lower 25-hydroxyvitamin D (p=0.006; 95% CI:1.4-8.0) and increased odds of 25-hydroxyvitamin D <50 nmol/L (OR 1.9, 95% CI:1.3–2.9). After adjustment for known vitamin D determinants, cow’s milk intake, vitamin D supplements, season and age were significant covariates and current vitamin D supplementation had the strongest confounding effect. In order to use the ethnicity variable, we developed a new standardized geographically based closed-ended ethnicity question, which was a practical alternative to the widely used open-ended ethnicity questions. There was an association between non-western immigration and lower 25-hydroxyvitamin D in early childhood and this appears primarily related to known vitamin D determinants.