Our sample included 16,718 participants with complete data (mean age 11.1 years (standard deviation; SD 2.8); 50.5% male) from the 17,263 youth (6–18 years of age) recruited at the Ontario Science Centre, a local science museum in Toronto, Canada. Informed consent, and assent where applicable, was obtained and the protocol was approved by The Hospital for Sick Children Research Ethics Board. We collected behavioral information about the participants from themselves if they were thought to be capable of self-reporting (18.2%) or from their parents (81.8%). Participants provided a saliva DNA sample using 2 mL Oragene® kits (DNA Genotek, Ottawa, Canada).
