Vitamin D status in preschool children and its relations to vitamin D sources and body mass index-Fish Intervention Studies-KIDS (FINS-KIDS)

Objectives The aims of this study were to determine vitamin D status (serum 25-hydroxyvitamin D3 [s-25(OH)D3]) and examine possible associations between vitamin D status and vitamin D–rich dietary sources, sun exposure, and body mass index in preschool children ages 4 to 6 y. Methods This is a cross-sectional study based on baseline data (collected in January-February 2015) from the two-armed randomized controlled trial Fish Intervention Studies-KIDS (FINS-KIDS) conducted in Bergen, Norway. S-25(OH)D3 concentration was determined by liquid chromatography–tandem mass spectrometry. Information regarding habitual dietary intake, recent sun vacations, and body mass index were assessed with questionnaires answered by the children's caregivers. Results The children (n = 212) had a mean (standard deviation) s-25(OH)D3 of 60.7 (13.8) nmol/L; 18.9% had s-25(OH)D3 ≤50 nmol/L. In logistic regression models, non-overweight versus overweight status was inversely associated with s-25(OH)D3 ≤50 nmol/L (odds ratio: 0.41; 95% confidence interval, 0.18–0.95; P = 0.037). Non-sun versus sun vacations were associated with s-25(OH)D3 ≤75 nmol/L (odds ratio: 5.33; 95% confidence interval, 1.93–14.77; P = 0.001). Conclusions The majority of the preschool children (81%) had s-25(OH)D3 >50 nmol/L. Children with overweight status had an increased risk of s-25(OH)D3 ≤50 nmol/L, and children who had not been on sun vacations were at a greater risk of s-25(OH)D3 ≤75 nmol/L.