[1] Univ Florida, Dept Pharmaceut Outcomes & Policy, Gainesville, FL USA
[2] US FDA, Dept Epidemiol, Silver Spring, MD USA
[3] Univ British Columbia, Dept Med, Child & Family Res Inst, Vancouver, BC, Canada
[4] McGill Univ, Dept Med, Montreal, PQ, Canada
[5] McGill Univ, Dept Epidemiol, Montreal, PQ, Canada
[6] Univ Washington, Dept Epidemiol, Seattle, WA 98195 USA