Vitamin D Intake and Status in 6-Year-Old Icelandic Children Followed up from Infancy

• Published in: Nutrients Vol. 8; no. 2; p. 75
• Main Authors: Thorisdottir, Birna, Gunnarsdottir, Ingibjorg, Steingrimsdottir, Laufey, Palsson, Gestur I, Birgisdottir, Bryndis E, Thorsdottir, Inga
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 04.02.2016; MDPI
• Subjects: 25-Hydroxyvitamin D; Age; Breast feeding; Child; Child Health; Child, Preschool; Children; Confidence intervals; Diet; Dietary Supplements; Female; Follow-Up Studies; Health risk assessment; Humans; Iceland - epidemiology; Infant; Infant Health; Infants; Logistic Models; Male; Motivation; Nutritional Status; Seasons; Statistical analysis; Sunlight; tracking; Vitamin D; Vitamin D - administration & dosage; Vitamin D - analogs & derivatives; Vitamin D - blood; Vitamin D Deficiency - blood; Vitamin D Deficiency - epidemiology; Vitamins - administration & dosage; Vitamins - blood; dietary supplements; seasons; 25-hydroxyvitamin D; tracking; vitamin D; child
• ISSN: 2072-6643; 2072-6643
• DOI: 10.3390/nu8020075

High serum 25-hydroxyvitamin D (25(OH)D) levels have been observed in infants in Nordic countries, likely due to vitamin D supplement use. Internationally, little is known about tracking vitamin D status from infancy to childhood. Following up 1-year-old infants in our national longitudinal cohort, our aims were to study vitamin D intake and status in healthy 6-year-old Icelandic children (n = 139) and to track vitamin D status from one year of age. At six years, the mean 25(OH)D level was 56.5 nmol/L (SD 17.9) and 64% of children were vitamin D sufficient (25(OH)D ≥ 50 nmol/L). A logistic regression model adjusted for gender and breastfeeding showed that higher total vitamin D intake (Odds ratio (OR) = 1.27, 95% confidence interval (CI) = 1.08-1.49), blood samples collected in summer (OR = 8.88, 95% CI = 1.83-43.23) or autumn (OR = 5.64, 95% CI = 1.16-27.32) compared to winter/spring, and 25(OH)D at age one (OR = 1.02, 95% CI = 1.002-1.04) were independently associated with vitamin D sufficiency at age six. The correlation between 25(OH)D at age one and six was 0.34 (p = 0.003). Our findings suggest that vitamin D status in infancy, current vitamin D intake and season are predictors of vitamin D status in early school age children. Our finding of vitamin D status tracking from infancy to childhood provides motivation for further studies on tracking and its clinical significance.