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Use of oral contraceptives, intrauterine devices and tubal sterilization and cancer risk in a large prospective study, from 1996 to 2006
Author(s) -
Dorjgochoo Tsogzolmaa,
Shu XiaoOu,
Li HongLan,
Qian HanZhu,
Yang Gong,
Cai Hui,
Gao YuTang,
Zheng Wei
Publication year - 2009
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.24232
Subject(s) - medicine , gynecology , obstetrics , hazard ratio , thyroid cancer , breast cancer , prospective cohort study , cohort study , stomach cancer , population , cancer , ovarian cancer , endometrial cancer , confidence interval , environmental health
The association of contraceptive methods, including oral contraceptives (OC), intrauterine devices (IUD) and tubal sterilization (TS), with overall and site‐specific cancer were prospectively investigated in a cohort of 66,661 Chinese women in Shanghai, 76.7% of whom used contraception. During a median follow‐up time of 7.5 years, 2,250 women were diagnosed with cancer. Ever‐use of any contraceptive method was not associated with overall cancer risk [adjusted hazard ratio (HR adj ) = 1.02, 95% CI, 0.92–1.12]. Use of any contraceptive method was associated with increased risk of rectal cancer (HR adj = 1.68, 95% CI, 1.08–2.62) and reduced risk of thyroid cancer (HR adj = 0.63, 95% CI, 0.38–1.04). Risk of gallbladder cancer increased with ever use of OC (HR adj = 2.38, 95% CI, 1.26–4.49). IUD use was associated with a possible reduced risk of thyroid cancer (HR adj = 0.64, 95% CI, 0.38–1.07). Longer duration of IUD use decreased risk for breast, thyroid and lung cancers. Ever having a TS was associated with increased uterine body cancer (HR adj = 2.50, 95% CI, 1.47–4.25) and decreased risk of stomach cancer (HR adj = 0.59, 95% CI, 0.39–0.91). We did not find any contraceptive method to be related to the risk of ovarian cancer but the analyses were based on few events. Although chance findings are a likely explanation for some of the associations found in our study, these findings suggest that various contraceptive methods or reproductive patterns may play a role in the etiology of cancer. © 2008 Wiley‐Liss, Inc.