[1] Columbia Univ, Mailman Sch Publ Hlth, New York, NY USA
[2] Univ Ottawa, Sch Epidemiol & Publ Hlth, Fac Med, 600 Peter Morand Crescent, Ottawa, ON K1G 5Z3, Canada
[3] Univ Saskatchewan, Hlth Surveillance & Reporting, Saskatchewan Hlth Author, Community Hlth & Epidemiol, Saskatoon, SK, Canada
[4] Univ Saskatchewan, Sch Publ Hlth, Saskatoon, SK, Canada