Oral contraceptive and IUD use and endometrial cancer: a population-based case-control study in Shanghai, China.
Oral contraceptive (OC) and intrauterine device (IUD) use have been shown to be protective factors for endometrial cancer in several epidemiological studies; however, few studies have been conducted in Chinese populations. We evaluated the association between OC and IUD use and endometrial cancer risk in a population-based case-control study among Chinese women in Shanghai, China. The study included 1,204 newly diagnosed endometrial cancer cases and 1,212 age frequency-matched healthy controls. Logistic regression models were used to estimate adjusted odds ratios (OR) and their 95% confidence intervals (95% CI). In our study population, 18.5% cases and 24.9% controls reported having ever used OCs with an OR of 0.75 (95% CI, 0.60-0.93), after adjusting for known risk or protective factors for endometrial cancer. The risk of endometrial cancer decreased with long-term use of OCs with the OR for more than 72 months of use being 0.50 (95% CI, 0.30-0.85). The effect of OC use remained 25 or more years after cessation of use; the associated OR was 0.57 (95% CI = 0.42-0.78) as compared to nonusers. Similarly, fewer cases than controls had ever used IUD, with the multivariable adjusted OR being 0.53 (95% CI = 0.43-0.65). A reduction in risk was observed regardless the duration of use or age at first and last use. These results suggest that OC and IUD use may confer long-term protection against endometrial cancer.
Tao
Meng Hua
MH
Department of Medicine, Center for Health Services Research, Vanderbilt-Ingram Cancer Center,Vanderbilt University School of Medicine, Nashville, TN 37232-8300, USA.
Xu
Wang Hong
WH
Zheng
Wei
W
Zhang
Zuo-Feng
ZF
Gao
Yu-Tang
YT
Ruan
Zhi Xian
ZX
Cheng
Jia Rong
JR
Gao
Jing
J
Xiang
Yong Bing
YB
Shu
Xiao Ou
XO
D000328:Adult; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D003276:Contraceptives, Oral / Q000009:adverse effects*; D016889:Endometrial Neoplasms / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007434:Intrauterine Devices / Q000009:adverse effects*; D008875:Middle Aged; D012307:Risk Factors; D012907:Smoking; D012959:Socioeconomic Factors; D013997:Time Factors
D003276:Contraceptives, Oral