[1] Univ British Columbia, Dept Pediat, Pediat Residency Program, Vancouver, BC V6T 1W5, Canada
[2] Univ British Columbia, Dept Pediat, Div Emergency Med, Vancouver, BC V6T 1W5, Canada
[3] Univ Calgary, Dept Med, Div Rheumatol, Calgary, AB, Canada
[4] Hlth Canada, Food Directorate, Ottawa, ON K1A 0L2, Canada
[5] Montreal Childrens Hosp, Dept Pediat, Emergency Dept, Montreal, PQ H3H 1P3, Canada
[6] Univ British Columbia, Dept Pediat, Div Allergy & Immunol, Fac Med,BC Childrens Hosp, Vancouver, BC V6T 1W5, Canada
[7] Univ British Columbia, Vancouver, BC V5Z 1M9, Canada
[8] McGill Univ, Dept Med, Ctr Hlth, Div Clin Epidemiol, Montreal, PQ, Canada
[9] Montreal Childrens Hosp, Dept Pediat, Div Clin Immunol & Allergy, Montreal, PQ H3H 1P3, Canada