Journal of Epidemiology
Online ISSN : 1349-9092
Print ISSN : 0917-5040
ISSN-L : 0917-5040
Original Article
Hormonal Contraceptive Use and Breast Cancer in Thai Women
Arisara PoosariSupannee PromthetSiriporn Kamsa-ardKrittika SuwanrungruangJirapat LongkulSurapon Wiangnon
ジャーナル フリー

2014 年 24 巻 3 号 p. 216-220


Background: Breast cancer is the most common cancer in women worldwide. We investigated the association of hormonal contraceptive use and breast cancer in Thai women.
Methods: A cohort study was conducted in Khon Kaen, Thailand. There were 70 cases of histologically confirmed breast cancer among 11 414 women aged 30 to 69 years who were recruited as participants in the cohort study during the period from 1990 through 2001. The study population was followed-up until December 31, 2011. To identify factors associated with incidence of breast cancer, hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using a Cox proportional hazards model.
Results: The 11 414 women provided a total observation time of 157 200 person-years. Breast cancer risk among women with a history of hormonal contraceptive use was 1.31 times that of women without such a history, but the difference was not statistically significant (95% CI, 0.65–2.65). No type of hormonal contraceptive was associated with a significant increase in breast cancer risk as compared with women who had never used hormonal contraceptives (oral contraception: HR = 1.35, 95% CI, 0.65–2.78; injection contraception: HR = 1.25, 95% CI, 0.56–2.80), and there was no relationship between duration of hormonal contraceptive use and breast cancer.
Conclusions: There was no association between hormonal contraceptive use and breast cancer; however, this finding should be viewed with caution due to the small number of cases.

© 2014 Arisara Poosari et al. This is an open access article distributed under the terms of Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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