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Cigarette smoking and the risk of ovarian cancer in the Japanese population: Findings from the Japanese Collaborate Cohort study
Author(s) -
Niwa Yoshimitsu,
Wakai Kenji,
Suzuki Sadao,
Tamakoshi Koji,
Lin Yingsong,
Yatsuya Hiroshi,
Kondo Takaaki,
Nishio Kazuko,
Yamamoto Akio,
Tokudome Shinkan,
Hamajima Nobuyuki,
Toyoshima Hideaki,
Tamakoshi Akiko
Publication year - 2005
Publication title -
journal of obstetrics and gynaecology research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.597
H-Index - 50
eISSN - 1447-0756
pISSN - 1341-8076
DOI - 10.1111/j.1447-0756.2005.00261.x
Subject(s) - medicine , relative risk , confidence interval , ovarian cancer , cohort study , confounding , cohort , proportional hazards model , population , cancer , demography , gynecology , environmental health , sociology
Aim: The many studies into the relation between cigarette smoking and the risk of ovarian cancer have produced inconsistent results. Here we investigated this relation using data from the Japan Collaborative Cohort Study for Evaluation of Cancer Risk, initiated in 1988. Methods: A self‐administered questionnaire on smoking habits and other risk factors for cancer was completed by 34 639 Japanese women. After 7.6 years of follow up, 39 cases of ovarian cancer were available for analyses. Cox proportional‐hazards models were used to compute relative risks (RR) and to adjust for confounders. Results: Relative to those who had never smoked, the RR of ovarian cancer were 1.63 (95% confidence interval [CI] = 0.21–12.50) for former smokers and 2.27 (95% CI = 0.85–6.08) for current smokers. Among current smokers, the RR were 1.48 (95% CI = 0.20–10.92), 5.56 (95% CI = 1.68–19.06), and 1.86 (95% CI = 0.25–14.30) among women who smoked <10, 10–19, and at least 20 pack‐years ([number of cigarettes smoked per day/20] × number of years subject has smoked), respectively, relative to those who had never smoked. A test for trend was statistically significant ( P = 0.044). Conclusions: These data indicate that cigarette smoking increases the risk of developing ovarian cancer in the Japanese population.