Association between allergies, asthma, and breast cancer risk among women in Ontario, Canada
Menée au Canada auprès de 3 101 cas et de 3 471 témoins, cette étude évalue l'association entre des allergies, de l'asthme, le rhume des foins et le risque de cancer du sein
Purpose : To investigate the association between allergies, asthma, and breast cancer risk in a large, population-based case–control study. Methods : Breast cancer cases (n = 3,101) were identified using the Ontario Cancer Registry and population controls (n = 3,471) through random digit dialing. Self-reported histories of allergies, hay fever, and asthma were collected by questionnaire. Logistic regression was used to assess associations between breast cancer risk and history of allergy/hay fever and asthma, with 16 possible confounders examined. Analyses were stratified by menopausal status. Results : A history of allergies or hay fever was associated with a small reduction in breast cancer risk [age-adjusted odds ratio (AOR) = 0.86, 95 % confidence interval (CI) 0.77–0.96] and did not differ by menopausal status. Asthma was not associated with breast cancer risk overall; however, among premenopausal women, asthma was associated with a reduced risk of breast cancer (AOR = 0.72, 95 % CI 0.54–0.97). Conclusions : A history of allergies may be associated with a modest reduction in breast cancer risk. Asthma does not appear to be associated with breast cancer risk overall; however, asthma may be associated with reduced breast cancer risk among premenopausal women