Vitamin D supplementation and vitamin D status in children of immigrant background in Norway.

OBJECTIVE: Sufficient vitamin D status during infancy is important for child health and development. Several initiatives for improving vitamin D status among immigrant children have been implemented in Norway. The present study aimed to evaluate the vitamin D status and its determinants in children of immigrant background in Oslo.

DESIGN: Cross-sectional study.

SETTING: Child health clinics in Oslo.

SUBJECTS: Healthy children with immigrant background (n 102) aged 9-16 months were recruited at the routine one-year check-up from two child health clinics with high proportions of immigrant clients. Blood samples were collected using the dried blood spot technique and analysed for serum 25-hydroxyvitamin D (s-25(OH)D) concentration using LC-MS/MS.

RESULTS: Mean s-25(OH)D was 52·3 (sd 16·7) nmol/l, with only three children below 25 nmol/l and none below 12·5 nmol/l. There was no significant gender, ethnic or seasonal variation in s-25(OH)D. However, compared with breast-fed children, s-25(OH)D concentration was significantly higher among children who were about 1 year of age and not breast-fed. About 38 % of the children were anaemic, but there was no significant correlation between s-25(OH)D and Hb (Pearson correlation, r=0·1, P=0·33).

CONCLUSIONS: Few children in the study had vitamin D deficiency, but about 47 % of the children in the study population were under the recommended s-25(OH)D sufficiency level of ≥50 nmol/l.