[1] Univ Cape Town, ZA-7925 Cape Town, Western Cape, South Africa
[2] Univ Toronto, Div Clin Publ Hlth, Toronto, ON M5S 1A1, Canada
[3] Univ Toronto, Dalla Lana Sch Publ Hlth, Dept Family & Community Med, Toronto, ON M5S 1A1, Canada
[4] Bridgepoint Collaboratory Res & Innovat, Toronto, ON, Canada