Carcinoma of the cervix and tobacco smoking: Collaborative reanalysis of individual data on 13,541 women with carcinoma of the cervix and 23,017 women without carcinoma of the cervix from 23 epidemiological studies†
Version of Record online: 4 OCT 2005
Copyright © 2005 Wiley-Liss, Inc.
International Journal of Cancer
Volume 118, Issue 6, pages 1481–1495, 15 March 2006
How to Cite
International Collaboration of Epidemiological Studies of Cervical Cancer (2006), Carcinoma of the cervix and tobacco smoking: Collaborative reanalysis of individual data on 13,541 women with carcinoma of the cervix and 23,017 women without carcinoma of the cervix from 23 epidemiological studies. Int. J. Cancer, 118: 1481–1495. doi: 10.1002/ijc.21493
Writing and analysis committee: Appleby P, Beral V, Berrington de González A, Colin D, Franceschi S, Goodill A, Green J, Peto J, Plummer M, Sweetland S.
Steering committee: La Vecchia C (Chairman), Bosch FX, Herrero R, Hildesheim A, Skegg D, Thomas D.
Collaborators: Rajkumar T, Cancer Institute (WIA), Chennai, India; Cuzick J, Cancer Research UK Epidemiology Group, Wolfson Institute of Preventive Medicine, UK; Appleby P, Beral V, Berrington de González A, Bull D, Crossley B, Green J, Reeves G, Sweetland S, Cancer Research UK Epidemiology Unit, Oxford, UK; Kjaer S, Danish Cancer Society, Denmark; Peto J, Department of Epidemiology and Population Health, LSHTM, London, UK; Painter R, Vessey M, Department of Public Health, Oxford, UK; Daling J, Madeleine M, Ray R, Thomas D, Fred Hutchinson Cancer Research Center, Seattle, USA; Hererro R, Guanacaste Epidemiological Project, Costa Rica; Ylitalo N, Department of Medical Epidemiology and Biostatistics, Karolinska Institut, Sweden; Bosch FX, Castellsague X, Institut Català d'Oncologia, Spain; Hammouda D, Institut Nacional de Santé Publique, Algiers, Algeria; Peto J, Institute of Cancer Research, Sutton, UK; Negri E, Istituto di Ricerche Farmacologiche ‘Mario Negri’, Milan, Italy; Santos C, Instituto Nacional de Enfermedades Neopláscias ‘Dr Eduardo Caceres Grazini’, Lima, Peru; Colin D, Franceschi S, Muñoz N, Plummer M, International Agency for Research on Cancer, Lyon, France; Dillner J, Silins I, Lund University, Mälmo, Sweden; Bayo S, Ministere de la Sante Publique et d'Affaires Sociales, Bamako, Mali; Chaouki N, Ministry of Health, Morocco; Rolon P, Ministry of Health, Paraguay; Brinton L, Hildesheim A, Lacey J, Jr, Schiffman M, National Cancer Institute, NIH, USA; Stein L, Urban MI, Cancer Epidemiology Research Group, National Health Laboratory Service, Johannesburg, South Africa; Hannaford P, Royal College of General Practitioners Oral Contraception Study, UK; Chichareon S, Prince of Songkla University, Songkla, Thailand; Sitas F, The Cancer Council New South Wales, Sydney, Australia; Eluf-Neto J, Universidade de São Paulo, Brazil; La Vecchia C, University of Milan, Italy; Skegg D, University of Otago, New Zealand; Pike M, Ursin G, University of Southern California, USA; Ngelangel C, University of the Philippines, Manila, The Philippines; Gram IT, University of Tromsø, Norway; Farley T, Meirik O, World Health Organization, Geneva, Switzerland.
- Issue online: 18 JAN 2006
- Version of Record online: 4 OCT 2005
- Manuscript Accepted: 22 JUL 2005
- Manuscript Received: 11 MAR 2005
- The UNDP/UNFPA/WHO/World Bank Special Program of Research, Development, and Research Training in Human Reproduction, Department of Human Reproductive Health and Research, WHO, Geneva
- Cancer Research, UK
- cervical cancer;
Tobacco smoking has been classified as a cause of cervical cancer, but the effect of different patterns of smoking on risk is unclear. The International Collaboration of Epidemiological Studies of Cervical Cancer has brought together and combined individual data on 13,541 women with and 23,017 women without cervical carcinoma, from 23 epidemiological studies. Relative risks (RRs) and 95% confidence intervals (CIs) of carcinoma of the cervix in relation to tobacco smoking were calculated with stratification by study, age, sexual partners, age at first intercourse, oral contraceptive use and parity. Current smokers had a significantly increased risk of squamous cell carcinoma of the cervix compared to never smokers (RR = 1.60 (95% CI: 1.48–1.73), p<0.001). There was increased risk for past smokers also, though to a lesser extent (RR = 1.12 (1.01–1.25)), and there was no clear trend with time since stopping smoking (p-trend = 0.6). There was no association between smoking and adenocarcinoma of the cervix (RR = 0.89 (0.74–1.06) and 0.89 (0.72–1.10) for current and past smokers respectively), and the differences between the RRs for smoking and squamous cell and adenocarcinoma were statistically significant (current smoking p<0.001 and past smoking p = 0.01). In current smokers, the RR of squamous cell carcinoma increased with increasing number of cigarettes smoked per day and also with younger age at starting smoking (p<0.001 for each trend), but not with duration of smoking (p-trend = 0.3). Eight of the studies had tested women for cervical HPV-DNA, and in analyses restricted to women who tested positive, there was a significantly increased risk in current compared to never smokers for squamous cell carcinoma (RR = 1.95 (1.43–2.65)), but not for adenocarcinoma (RR = 1.06 (0.14–7.96)). In summary, smokers are at an increased risk of squamous cell but not of adenocarcinoma of the cervix. The risk of squamous cell carcinoma increases in current smokers with the number of cigarettes smoked per day and with younger age at starting smoking. © 2005 Wiley-Liss, Inc.