Predictors of vitamin D supplementation amongst infants in Ireland throughout the first year of life

To investigate predictors of compliance with the recommendation that all infants in Ireland are supplemented daily from birth to 12 months of age with 5 mu g of vitamin D. A prospective observational study was conducted. Self-complete questionnaires recorded socio-demographic characteristics, health behaviours and supplementation practices for 158 mother-infant dyads at 4, 9 and 12 months post-partum. A 2-day food diary was also obtained on 12-month-old infants to examine the contribution of diet to vitamin D intakes. At 4, 9 and 12 months of age, 57.6% (n = 91), 34.2% (n = 54) and 23.4% (n = 37) of infants, respectively, were supplemented as recommended. In multivariate analyses, receiving supplementation advice from health professionals in the early post-partum period was the most significant predictor of correctly supplementing 4-month-old [p < 0.01; odds ratio, OR: 61.94 (95% confidence interval, CI: 11.53-332.83)], 9-month-old [p < 0.01, OR: 10.30 (95% CI: 2.29-46.27)] and 12-month-old [p = 0.04, OR: 3.85 (95% CI: 1.05-14.08)] infants. Amongst 12 month olds, mean intakes from diet and supplementation combined (7.6 +/- 4.7 mu g/day) were suboptimal. Suboptimal vitamin D supplementation practices were evident throughout infancy. Dietary intakes of vitamin D did not compensate for suboptimal supplementation practices. Supplementation practices may improve if health professionals advocate safe supplementation during routine infant health checks.