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- Beral, Valerie, et al.
(författare)
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Breast cancer and abortion: collaborative reanalysis of data from 53 epidemiological studies, including 83?000 women with breast cancer from 16 countries
- 2004
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Ingår i: The Lancet. - 1474-547X. ; 363:9414, s. 1007-1016
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The Collaborative Group on Hormonal Factors in Breast Cancer has brought together the worldwide epidemiological evidence on the possible relation between breast cancer and previous spontaneous and induced abortions. METHODS: Data on individual women from 53 studies undertaken in 16 countries with liberal abortion laws were checked and analysed centrally. Relative risks of breast cancer--comparing the effects of having had a pregnancy that ended as an abortion with those of never having had that pregnancy--were calculated, stratified by study, age at diagnosis, parity, and age at first birth. Because the extent of under-reporting of past induced abortions might be influenced by whether or not women had been diagnosed with breast cancer, results of the studies--including a total of 44000 women with breast cancer--that used prospective information on abortion (ie, information that had been recorded before the diagnosis of breast cancer) were considered separately from results of the studies--including 39000 women with the disease--that used retrospective information (recorded after the diagnosis of breast cancer). FINDINGS: The overall relative risk of breast cancer, comparing women with a prospective record of having had one or more pregnancies that ended as a spontaneous abortion versus women with no such record, was 0.98 (95% CI 0.92-1.04, p=0.5). The corresponding relative risk for induced abortion was 0.93 (0.89-0.96, p=0.0002). Among women with a prospective record of having had a spontaneous or an induced abortion, the risk of breast cancer did not differ significantly according to the number or timing of either type of abortion. Published results on induced abortion from the few studies with prospectively recorded information that were not available for inclusion here are consistent with these findings. Overall results for induced abortion differed substantially between studies with prospective and those with retrospective information on abortion (test for heterogeneity between relative risks: chi2(1) =33.1, p<0.0001). INTERPRETATION: Pregnancies that end as a spontaneous or induced abortion do not increase a woman's risk of developing breast cancer. Collectively, the studies of breast cancer with retrospective recording of induced abortion yielded misleading results, possibly because women who had developed breast cancer were, on average, more likely than other women to disclose previous induced abortions.
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| 2. |
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| 3. |
- Menvielle, Gwenn, et al.
(författare)
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The Contribution of Risk Factors to the Higher Incidence of Invasive and In Situ Breast Cancers in Women With Higher Levels of Education in the European Prospective Investigation Into Cancer and Nutrition
- 2011
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Ingår i: American Journal of Epidemiology. - : Oxford University Press (OUP). - 0002-9262 .- 1476-6256. ; 173:1, s. 26-37
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Tidskriftsartikel (refereegranskat)abstract
- The authors investigated the role of known risk factors in educational differences in breast cancer incidence. Analyses were based on the European Prospective Investigation Into Cancer and Nutrition and included 242,095 women, 433 cases of in situ breast cancer, and 4,469 cases of invasive breast cancer. Reproductive history (age at first full-term pregnancy and parity), exposure to endogenous and exogenous hormones, height, and health behaviors were accounted for in the analyses. Relative indices of inequality (RII) for education were estimated using Cox regression models. A higher risk of invasive breast cancer was found among women with higher levels of education (RII = 1.22, 95% confidence interval (CI): 1.09, 1.37). This association was not observed among nulliparous women (RII = 1.13, 95% CI: 0.84, 1.52). Inequalities in breast cancer incidence decreased substantially after adjusting for reproductive history (RII = 1.11, 95% CI: 0.98, 1.25), with most of the association being explained by age at first full-term pregnancy. Each other risk factor explained a small additional part of the inequalities in breast cancer incidence. Height accounted for most of the remaining differences in incidence. After adjusting for all known risk factors, the authors found no association between education level and risk of invasive breast cancer. Inequalities in incidence were more pronounced for in situ breast cancer, and those inequalities remained after adjustment for all known risk factors (RII = 1.61, 95% CI: 1.07, 2.41), especially among nulliparous women.
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| 4. |
- Reeves, Gillian K., et al.
(författare)
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Breast cancer risk in relation to abortion: Results from the EPIC study
- 2006
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 119:7, s. 1741-1745
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Tidskriftsartikel (refereegranskat)abstract
- The role of spontaneous and induced abortion on breast cancer risk is examined among 267,361 women recruited into the European Prospective Investigation into Cancer and nutrition between 1992 and 2000. The data were collected from 20 centers, across 9 countries, and included information on a total of 4,805 women with breast cancer, of whom 1,657 reported having ever had any type of abortion. Overall, the relative risk of breast cancer in women who reported ever having had a spontaneous abortion was not significantly elevated when compared with women who reported never having had such an abortion (RR = 1.07, 95 % CI = 0.99-1.14). However, there was some evidence of a slight increase in the risk of breast cancer among women who reported having had 2 or more spontaneous abortions (1.20,1.07-1.35). The relative risk of breast cancer among women who reported ever having had an induced abortion when compared to women who reported never having had an induced abortion was 0.95 (0.87-1.03). Overall, the findings provide further unbiased evidence of the lack of an adverse effect of induced abortion on breast cancer risk. (c) 2006 Wiley-Liss, Inc.
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| 5. |
- Tjonneland, Anne, et al.
(författare)
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Alcohol intake and breast cancer risk: the European Prospective Investigation into Cancer and Nutrition (EPIC)
- 2007
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Ingår i: Cancer Causes and Control. - : Springer Science and Business Media LLC. - 1573-7225 .- 0957-5243. ; 18:4, s. 361-373
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Tidskriftsartikel (refereegranskat)abstract
- Objective Most epidemiologic studies have suggested an increased risk of breast cancer with increasing alcohol intake. Using data from 274,688 women participating in the European Prospective Investigation into Cancer and Nutrition study (EPIC), we investigated the relation between alcohol intake and the risk of breast cancer. Methods Incidence rate ratios (IRRs) based on Cox proportional hazard models were calculated using reported intake of alcohol, recent (at baseline) and lifetime exposure. We adjusted for known risk factors and stratified according to study center as well as potentially modifying host factors. Results During 6.4 years of follow up, 4,285 invasive cases of breast cancer within the age group 35-75 years were identified. For all countries together the IRR per 10 g/day higher recent alcohol intake (continuous) was 1.03 (95% confidence interval (CI): 1.01-1.05). When adjusted, no association was seen between lifetime alcohol intake and risk of breast cancer. No difference in risk was shown between users and non-users of HRT, and there was no significant interaction between alcohol intake and BMI, HRT or dietary folate. Conclusion This large European study supports previous findings that recent alcohol intake increases the risk of breast cancer.
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