Keiko Wada, Chisato Nagata, Mai Utada, Ritsu Sakata, Takashi Kimura, Akiko Tamakoshi, Yumi Sugawara, Ichiro Tsuji, Ren Sato, Norie Sawada, Shoichiro Tsugane, Isao Oze, Hidemi Ito, Tetsuhisa Kitamura, Yuriko N Koyanagi, Yingsong Lin, Keitaro Matsuo, Sarah K Abe, Manami Inoue
BACKGROUND: Epidemiological studies have shown inconsistent results regarding the link between smoking and breast cancer risk, despite the biological plausibility of a positive association. METHODS: Participants were 166 611 women from nine prospective cohort studies in Japan which launched in 1984-1994 and followed for 8-22 years. Information on smoking and secondhand smoke was obtained through self-administered baseline questionnaires. Breast cancer was defined as code C50 according to the International Classification of Diseases for Oncology, 3rd Edition or the International Classification of Diseases, 10th Revision...
April 11, 2024: International Journal of Epidemiology