Trends in smoking by birth cohorts born between 1900 and 1977 in Japan Tomomi Marugame a, * , Ken-ichi Kamo b , Tomotaka Sobue a , Suminori Akiba c , Shoichi Mizuno d , Hiroshi Satoh e , Takaichiro Suzuki f , Kazuo Tajima g , Akiko Tamakoshi h , Shoichiro Tsugane i a Statistics and Cancer Control Division, Research Center for Cancer Prevention and Screening, National Cancer Center, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan b Division of Mathematics, School of Medicine, Liberal Arts and Sciences, Sapporo Medical University, Minami-1, Nishi-17, Chuo-ku, Sapporo, Hokkaido 060-8543, Japan c Department of Epidemiology and Preventive Medicine, Faculty of Medicine, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8520, Japan d Epidemiology and Health Promotion, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan e Environmental Health Sciences, Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan f Department of Cancer Control and Statistics, Osaka Medical Center for Cancer and Cardiovascular Diseases, 1-3-3 Nakamichi, Higashinari-ku, Osaka 537-8511, Japan g Division of Epidemiology and Prevention, Aichi Cancer Center Research Institute, 1-1 Kanokoden, Chikusa-ku, Nagoya 464-8681, Japan h Department of Preventive Medicine/Biostatistics and Medical Decision Making, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan i Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan Available online 3 November 2005 Abstract Background. The present study aimed to elucidate the changing patterns of smoking among successive birth cohorts in Japan. Methods. Birth-cohort-specific smoking prevalence was estimated for birth cohorts born from 1900 to 1952, using data pooled from four prospective studies (242,330 men and 274,075 women), and for birth cohorts born from 1925 to 1977, using National Nutrition Survey data. Results. For men, two peaks were observed in smoking prevalence, in the 1925 and late-1950s birth cohorts, while a trough was observed for the 1938 birth cohort. For women, ever smoking prevalence was lowest among the 1930s birth cohorts. After the female 1940s birth cohorts, no peak was observed until the end of our observations, the 1970s birth cohorts. Although Japanese women have historically tended to start smoking at later ages, recently, smoking habits have widely expanded among females in young birth cohorts. Conclusions. Smoking trends in Japanese men and women vary by birth cohorts. Smoking cessation should continue to be strongly promoted among men, although the younger generation has widely adopted a nonsmoking lifestyle. For women, efforts for preventing the onset of smoking, while necessary among the younger generation, should even be enhanced among middle-aged women. D 2005 Elsevier Inc. All rights reserved. Keywords: Smoking prevalence; Birth cohort; Pooled analysis; Japan Introduction Cigarette smoking is a major public health problem and is known to cause premature death. In Japan, estimates have indicated that among men 22% of all deaths, 25% of all cancer deaths, and 17% of all deaths from circulatory system diseases may be attributable to smoking (Hara et al., 2002), while, among women, these figures are 5%, 3%, and 11%, respec- tively (Hara et al., 2002). Trends in smoking prevalence according to age group have been monitored by annually repeated cross-sectional surveys conducted by Japan Tobacco Industry, Inc., and the National 0091-7435/$ - see front matter D 2005 Elsevier Inc. All rights reserved. doi:10.1016/j.ypmed.2005.09.009 * Corresponding author. Fax: +81 3 3546 0630. E-mail address: tmarugam@gan2.res.ncc.go.jp (T. Marugame). Preventive Medicine 42 (2006) 120 – 127 www.elsevier.com/locate/ypmed