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Cervical carcinoma and reproductive factors: Collaborative reanalysis of individual data on 16,563 women with cervical carcinoma and 33,542 women without cervical carcinoma from 25 epidemiological studies
Author(s) -
Thangarajan Rajkumar,
Jack Cuzick,
Paul N. Appleby,
Ruanne V. Barnabas,
Valerie Beral,
Amy Berrington de González,
Diana Bull,
Karen Canfell,
Barbara Crossley,
J. Green,
Gillian Reeves,
S Sweetland,
Susanne K. Kjær,
Rosemary Painter,
Martin Vessey,
Janet R. Daling,
Margaret M. Madeleine,
Roberta M. Ray,
David B. Thomas,
Rolando Herrero,
Nathalie Ylitalo,
F. Xavier Bosch,
Sílvia de Sanjosé,
Xavier Castellsagué,
Vı́ctor Moreno,
Doudja Hammouda,
Eva Negri,
Giorgia Randi,
Manuel Álvarez,
Óscar Galdós,
Carlos Santos,
Carlos Velarde,
Didier Colin,
Silvia Franceschi,
Núbia Muñóz,
Martyn Plummer,
Julian Peto,
Joakim Dillner,
Ilvars Silins,
S Bayo,
Noureddine Chaouki,
P A Rolón,
Louise A. Brinton,
Allan Hildesheim,
J. Lacey,
Mark Schiffman,
Lara Stein,
Margaret Urban,
Hannaford Pc,
Saibua Chichareon,
Freddy Sitas,
José Eluf-Neto,
Carlo La Vecchia,
Skegg Dc,
Ruth Peters,
Malcolm C. Pike,
Giske Ursin,
Corazon A. Ngelangel,
Inger Torhild Gram,
Timothy M.M. Farley,
Olav Meirik
Publication year - 2006
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.21953
Subject(s) - medicine , cervical cancer , carcinoma in situ , pregnancy , carcinoma , relative risk , epidemiology , gynecology , obstetrics , cervical intraepithelial neoplasia , cervical carcinoma , confidence interval , cancer , biology , genetics
Abstract The International Collaboration of Epidemiological Studies of Cervical Cancer has combined individual data on 11,161 women with invasive carcinoma, 5,402 women with cervical intraepithelial neoplasia (CIN)3/carcinoma in situ and 33,542 women without cervical carcinoma from 25 epidemiological studies. Relative risks (RRs) and 95% confidence intervals (CIs) of cervical carcinoma in relation to number of full‐term pregnancies, and age at first full‐term pregnancy, were calculated conditioning by study, age, lifetime number of sexual partners and age at first sexual intercourse. Number of full‐term pregnancies was associated with a risk of invasive cervical carcinoma. After controlling for age at first full‐term pregnancy, the RR for invasive cervical carcinoma among parous women was 1.76 (95% CI: 1.53–2.02) for ≥≥7 full‐term pregnancies compared with 1–2. For CIN3/carcinoma in situ , no significant trend was found with increasing number of births after controlling for age at first full‐term pregnancy among parous women. Early age at first full‐term pregnancy was also associated with risk of both invasive cervical carcinoma and CIN3/carcinoma in situ . After controlling for number of full‐term pregnancies, the RR for first full‐term pregnancy at age <17 years compared with ≥≥25 years was 1.77 (95% CI: 1.42–2.23) for invasive cervical carcinoma, and 1.78 (95% CI: 1.26–2.51) for CIN3/carcinoma in situ . Results were similar in analyses restricted to high‐risk human papilloma virus (HPV)‐positive cases and controls. No relationship was found between cervical HPV positivity and number of full‐term pregnancies, or age at first full‐term pregnancy among controls. Differences in reproductive habits may have contributed to differences in cervical cancer incidence between developed and developing countries. © 2006 Wiley‐Liss, Inc.