SELF-REPORTED STRESS AND RISK OF BREAST-CANCER

BACKGROUND. Many women attribute the development of their breast cance r to psychosocial factors such as stress and depression. Yet investiga tions of the relationship between breast cancer and stressful life eve nts have had inconsistent outcomes, due in part to studies with small sample sizes and reliance on hospital-based populations. METHODS. As p art of a population-based, case-control study of breast cancer etiolog y, we evaluated the association between stressful life events and the risk of breast cancer among 258 breast cancer patients and 614 randoml y selected population-based controls. Information on 11 stressful life events was collected in telephone interviews with women aged 50-79 wh o were participating in the ongoing study. RESULTS. Breast cancer pati ents and controls experienced the same number of stressful life events in the five years prior to diagnosis or an equivalent reference date (controls), averaging 2.4 and 2.6 events, respectively. After adjustme nt for known breast cancer risk factors, there was no association betw een weighted stressful life event scores and the risk of breast cancer (odds ratio [OR] = 0.90 per unit increase; 95% confidence interval [C I], 0.78-1.05). Only one life event, death of a close friend, was sign ificantly more often reported by controls (OR = 0.72; 95% CI, 0.52-1.0 0). Other life events were inconsistently and nonsignificantly associa ted with breast cancer risk. CONCLUSIONS. The results of this retrospe ctive study do not suggest any important associations between stressfu l life events and breast cancer risk. (C) 1996 American Cancer Society .