Cigarette smoking and postmenopausal breast cancer risk in a prospective cohort

Abstract

Background:The relationship between cigarette smoking and breast cancer risk has been inconsistent, potentially due to modification by other factors or confounding.Methods:We examined smoking and breast cancer risk in a prospective cohort of 186 150 female AARP (formerly American Association of Retired Persons) members, ages 50–71 years, who joined the study in 1995–96 by responding to a questionnaire. Through 2006, 7481 breast cancers were diagnosed. Multivariable-adjusted hazard ratios (HRs) were estimated, overall and stratified by breast cancer risk factors, using Cox proportional hazards regression. Multiplicative interactions were evaluated using the likelihood ratio test.Results:Increased breast cancer risk was associated with current (HR 1.19, 95% confidence interval (CI) 1.10–1.28) and former (HR 1.07, CI 1.01–1.13) smoking. The current smoking association was stronger among women without (HR 1.24, CI 1.15–1.35) as compared to those with a family history of breast cancer (HR 0.94, CI 0.78–1.13) (P-interaction=0.03). The current smoking association was also stronger among those with later (⩾15 years: HR 1.52, CI 1.20–1.94) as compared with earlier (⩽12 years: HR 1.14, CI 1.03–1.27; 13–14 years: HR 1.18, CI 1.05–1.32) ages at menarche (P-interaction=0.03).Conclusions:Risk was elevated in smokers, particularly in those without a family history or late menarche. Research into smoking's effects on the genome and breast development may clarify these relationships.

Association of the C677T polymorphism in the methylenetetrahydrofolate reductase gene with breast cancer in a Mexican population

“…In this context, these factors have been previously associated with BC (Davoodi et al, 2013;Greer et al, 2014;Nyante et al, 2014). In fact, there are several theories that attempt to explain the association of obesity with BC, which involve the roles of leptin, insulin, adipocytes, and other molecules that mediate the inflammatory process, peripheral circulating estrogens, and metabolic syndrome; these may in turn activate molecular processes that are mitogenic in breast epithelial cells and thereby stimulate neoplasia (Gómez Flores et al, 2013;Ramírez et al, 2013;Gallegos et al, 2014).…”

Cigarette Smoking and Breast Cancer Risk in Hispanic and Non-Hispanic White Women: The Breast Cancer Health Disparities Study

“…'' estimates for smoking by <10%, suggesting minimal confounding; however, we adjusted for alcohol in final models to maintain consistency with previous studies. Various studies have evaluated effect modification by alcohol consumption with the association between smoking and breast cancer risk; results have been mixed with some findings indicating no statistical evidence of effect modification [50][51][52] and other studies finding significant associations only among nondrinkers. 53,54 The CPS-II Nutrition Cohort reported significant associations among current drinkers for current (Hazard Ratio [HR] 1.36, 95% CI 1.14-1.36) and former (HR 1.19, 95% CI 1.09-1.31) smoking status, although the interaction was not statistically significant ( p = 0.11).…”

Social inequalities and smoking-associated breast cancer — Results from a prospective cohort study

“…The association between smoking and breast cancer is still under debate (Johnson et al, 2011;IARC. Internatinal Agency for Research on Cancer, 2012; U.S.Department of Health and Human Services, 2014). However, most recent, well conducted cohort studies of this relationship are relatively consistent with a 5-32% higher risk for current, and a 5-18% higher risk for former smokers, compared with never smokers (Reynolds et al, 2004;Nyante et al, 2014;Gram et al, 2005;Olson et al, 2005;Cui et al, 2006;Ha et al, 2007;Luo et al, 2011;Xue et al, 2011;DeRoo et al, 2011;Bjerkaas et al, 2013;Gaudet et al, 2013;Rosenberg et al, 2013;Dossus et al, 2014).…”

“…An increasing proportion of women in Norway will have high level of education in the future, adapting underlying breast cancer risk factors, increasing their risk for breast cancer in general. The past reductions in smoking prevalence among women in Norway will in the future reduce the incidence of smoking-associated diseases, which according to most recent studies (Reynolds et al, 2004;Nyante et al, 2014;Gram et al, 2005;Olson et al, 2005;Cui et al, 2006;Ha et al, 2007;Luo et al, 2011;Xue et al, 2011;DeRoo et al, 2011;Bjerkaas et al, 2013;Gaudet et al, 2013;Rosenberg et al, 2013;Dossus et al, 2014), includes breast cancer.…”