OBJECTIVE: To examine the use of vitamin D supplements during infancy among the participants in an international infant feeding trial.

DESIGN: Longitudinal study.

SETTING: Information about vitamin D supplementation was collected through a validated FFQ at the age of 2 weeks and monthly between the ages of 1 month and 6 months.

SUBJECTS: Infants (n 2159) with a biological family member affected by type 1 diabetes and with increased human leucocyte antigen-conferred susceptibility to type 1 diabetes from twelve European countries, the USA, Canada and Australia.

RESULTS: Daily use of vitamin D supplements was common during the first 6 months of life in Northern and Central Europe (>80% of the infants), with somewhat lower rates observed in Southern Europe (> 60%). In Canada, vitamin D supplementation was more common among exclusively breast-fed than other infants (e.g., 71% v. 44% at 6 months of age). Less than 2% of infants in the U.S.A. and Australia received any vitamin D supplementation. Higher gestational age, older maternal age and longer maternal education were study-wide associated with greater use of vitamin D supplements.

CONCLUSIONS: Most of the infants received vitamin D supplements during the first 6 months of life in the European countries, whereas in Canada only half and in the U.S.A. and Australia very few were given supplementation.