[1] McGill Univ, Sch Populat & Global Hlth, Dept Epidemiol Biostat & Occupat Hlth, Montreal, PQ, Canada
[2] Univ N Carolina, Gillings Sch Global Publ Hlth, Dept Epidemiol, Chapel Hill, NC USA
[3] Stanford Univ, Sch Med, Stanford, CA USA
[4] McGill Univ, Fac Med & Hlth Sci, Sch Populat & Global Hlth, Dept Epidemiol Biostat & Occupat Hlth, 2001 McGill Coll Ave,Suite 1200, Montreal, PQ H3A 1G1, Canada