Stressful life events and breast cancer risk: a hospital-based case-control study.

PURPOSE Elucidation of the factors contributing to the incidence of breast cancer is of crucial importance for the development of preventive or therapeutic strategies targeting the disease. Research on stress and breast cancer has been documented by various studies published over the years. In view of breast cancer importance as the most commonly occurring malignancy in females in Serbia, this study was undertaken to examine the association between stressful life events and breast cancer risk. METHODS The present hospital-based case-control study comprised 120 new breast cancer cases and 120 hospital controls matched with respect to age (± 2 years). This study used the Paykel Life Events Scale to obtain information about stressful life events in the years before diagnosis. The SPSS statistical package was used and odds ratios (OR) and 95% confidence intervals (95% CI) were calculated from multivariate conditional logistic regression model. RESULTS Multiple conditional logistic regression analysis revealed six independent predictors of breast cancer risk: experience of severe and moderate threats (first 25 life events from the scale) (OR=3.15, 95% CI=2.01-4.93), son's military service (OR=6.09, 95% CI=4.17-12.37), death of close family member (OR=7.98, 95% CI=2.18-9.14), moderate financial difficulties (OR=3.26, 95%CI=1.24-8.56), maternal death in childhood (OR=3.46, 95% CI=1.21-9.92) and serious financial difficulties (OR=3.55, 95% CI=1.20-10.52). CONCLUSION Stress exposure has been proposed to contribute to the etiology of breast cancer. There is a need for understanding the differing physiological effects of types or times of stress exposure.