1 Linda Perron, Marc Simard, Denis Hamel, and Ernest Lo are with the Institut national de santé publique du Québec, Quebec City, Canada. Linda Perron and Jacques Brisson are with the Département de médecine sociale et préventive, Québec-Université Laval, Quebec City. Jacques Brisson is also with the Centre de recherche du CHU de Québec-Université Laval, Centre hospitalier universitaire de Québec, Quebec City. Ernest Lo is also with the Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Canada.