Title |
Menstrual Cycle Characteristics and History of Ovulatory Infertility in Relation to Breast Cancer Risk in a Large Cohort of US Women
|
---|---|
Published in |
American Journal of Epidemiology, April 1998
|
DOI | 10.1093/oxfordjournals.aje.a009504 |
Pubmed ID | |
Authors |
Miriam Garland, David J. Hunter, Graham A. Colditz, JoAnn E. Manson, Meir J. Stampfer, Donna Spiegelman, Frank Speizer, Walter C. Willett |
Abstract |
Menstrual cycle characteristics and ovulatory infertility were evaluated in relation to breast cancer risk among 116,678 women in the Nurses' Health Study II, a prospective cohort study of female registered nurses who were aged 25-42 years and living in 14 US states at enrollment in 1989. During 396,299 person-years of follow-up between return of the baseline questionnaire and June 1993, 251 cases of breast cancer were identified in this cohort. The multivariate relative risk (RR) associated with age at menarche > 13 years compared with age < or = 12 years was 0.66 (95% confidence interval (CI) 0.44-0.99). Short and long menstrual cycle lengths at ages 18-22 years were associated with reduced risk. Compared with menstrual cycle length 26-31 days, the multivariate relative risks (95% CIs) for more extreme cycle lengths were: < 26 days, 0.50 (0.25-0.98); 32-39 days, 0.81 (0.51-1.28); and > 39 days or too irregular for estimation of a usual cycle length, 0.41 (0.18-0.94). The multivariate relative risk associated with a history of ovulatory infertility, compared with no such history, was 0.41 (95% CI 0.18-0.93). These results are consistent with the hypothesis that reduced exposure to ovulatory menstrual cycles provides a protective effect against breast cancer. |
Mendeley readers
Geographical breakdown
Country | Count | As % |
---|---|---|
Spain | 1 | 3% |
Portugal | 1 | 3% |
Unknown | 28 | 93% |
Demographic breakdown
Readers by professional status | Count | As % |
---|---|---|
Student > Postgraduate | 4 | 13% |
Student > Doctoral Student | 3 | 10% |
Researcher | 3 | 10% |
Student > Bachelor | 2 | 7% |
Unspecified | 2 | 7% |
Other | 6 | 20% |
Unknown | 10 | 33% |
Readers by discipline | Count | As % |
---|---|---|
Agricultural and Biological Sciences | 6 | 20% |
Medicine and Dentistry | 4 | 13% |
Unspecified | 2 | 7% |
Biochemistry, Genetics and Molecular Biology | 1 | 3% |
Psychology | 1 | 3% |
Other | 3 | 10% |
Unknown | 13 | 43% |