Received: 20 January 2021
Accepted: 27 May 2021
First Online: 7 July 2021
: This study was approved by the Research Ethics Boards at The Hospital for Sick Children and Unity Health Toronto. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee (TARGet Kids! is registered at ExternalRef removed; NCT01869530) and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
: Informed consent was obtained from all individual participants included in the study.
: Not applicable.
: Jonathon Maguire received an unrestricted research grant for a completed investigator-initiated study from the Dairy Farmers of Canada (2011–2012) and Ddrops provided non-financial support (vitamin D supplements) for an investigator-initiated study on vitamin D and respiratory tract infections (2011–2015). The other authors have no other conflicts of interest to disclose.
: The funding agencies had no role in the design and conduct of the study, the collection/analysis, interpretation of the data, or the preparation and approval of the manuscript.