Author Affiliations: Science Integration Division, Centre for Chronic Disease Prevention and Control, Public Health Agency of Canada, Ottawa, Ontario, Canada (Dr Johnson); Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada (Dr Miller); School of Public Health, University of California, Berkeley (Dr Hammond); and Canadian Expert Panel on Tobacco Smoke and Breast Cancer Risk and Physicians for a Smoke-Free Canada, Ottawa (Mr Collishaw).
The findings from the Nurses Health Study1 of increased breast cancer risk associated with longer duration of smoking, higher pack-years, younger age at smoking initiation, and smoking before first birth are consistent with those from 9 cohort studies recently summarized by the Canadian Expert Panel on Tobacco Smoke and Breast Cancer Risk.2
Johnson KC, Miller AB, Hammond SK, Collishaw NE. Analysis of Passive Smoking and Breast Cancer of Limited Value. Arch Intern Med. 2011;171(16):1508-1510. doi:10.1001/archinternmed.2011.383