[1] Hosp Sick Children, Toronto, ON, Canada
[2] Univ Toronto, Dept Pediat, Toronto, ON, Canada
[3] Univ Toronto, Ophthalmol & Visual Sci, Toronto, ON, Canada
[4] Univ Toronto, Dept Otolaryngol Head & Neck Surg, Toronto, ON, Canada
[5] Univ Toronto, Inst Hlth Policy Management & Evaluat, Toronto, ON, Canada
[6] Univ Toronto, North York Gen Hosp, Toronto, ON, Canada
[7] Univ Toronto, Dalla Lana Sch Publ Hlth, Toronto, ON, Canada
[8] SickKids Res Inst, Child Hlth Evaluat Sci, Toronto, ON, Canada
[9] Univ Montreal, Sch Publ Hlth, Dept Pediat, Montreal, PQ, Canada
[10] Univ Montreal, Sch Publ Hlth, Dept Social & Prevent Med, Montreal, PQ, Canada
[11] CHU Sainte Justine, Dept Pediat, Div Gen Pediat, Montreal, PQ, Canada
[12] Univ Ottawa, Childrens Hosp Eastern Ontario, Dept Pediat, Ottawa, ON, Canada
[13] McMaster Univ, McMaster Childrens Hosp, Dept Pediat, Hamilton, ON, Canada
[14] Univ Toronto, Dept Paediat, Trillium Hlth Partners, Mississauga, ON, Canada
[15] Univ Calgary, Alberta Childrens Hosp, Dept Pediat, Calgary, AB, Canada
[16] Univ Alberta, Stollery Childrens Hosp, Dept Pediat, Edmonton, AB, Canada
[17] Queens Univ, Dept Paediat, London, England
[18] Lakeridge Hlth, Res, Oshawa, ON, Canada
[19] Queens Univ, Kingston Hlth Sci Ctr, Kingston, ON, Canada