The Analysis Of Breast Cancer Risk Factors In Lanzhou City

Objective Breast cancer is one of the most common female cancers, which is a serious threat to women. Recently, it has increased quickly, especially in some economically developed regions and cities of China. In such regions, the incidence rate of breast cancer ranks as the first female malignancy. The incidence and development of breast cancer are the results of the in vivo and in vitro factors, and the etiology is still unclear. In this study, we used case-control study to explore the risk factors of breast cancer of women in Lanzhou city, to provide a reference basis for the prevention of breast cancer in women.Methods A hospital-based case-control study was conducted. The group of case came from the Maternal and Child-care Hospital of Gansu Province on January2005to January2010with pathologically confirmation.425cases of women with breast cancer were involved. The control group of healthy women were1108subjects who participating health examination. The contents of questionnaire include general information (gender, age, height, weight), the history of hormonal drug used, family history of breast cancer, previous history of breast benign diseases, menstrual and reproductive status/history and other contents.Results:In this study, there are significant difference in reproductive history, age of the first pregnancy, breast-feeding history, history of abortion, age at menarche, age at natural menopause, accumulative menstrual years, family history of breast cancer, history of hormonal drug use and history of previous benign diseases between case and control groups(P<0.05). Our results showed family history of breast cancer (OR=5.7895%CI=1.56～14.67), previous breast benign diseases(OR=1.66,95%CI=1.32～1.89) and prolonged the time during giving first birth to menarche age(OR=1.67,95%CI=1.43-1.86) are the risk factors of breast cancer. Breastfeeding history(OR=0.68,95%CI=0.38～0.85) and late age at menarche(OR=0.81,95%CI=0.41～0.97) are protective factors of breast cancer.To eliminate the influence of confounding factors, we used stratified analysis by menopausal status and found that in postmenopausal group, late age at menarche(OR=0.26,95%CI=0.16～0.42), full term pregnancy(OR=0.52,95%CI=0.33～0.82), no history of abortion (OR=0.44,95%CI=0.30～0.64) are the protective factors breast cancer. In the premenopausal group, prolonged the interval from first birth to menarche>17years (OR=1.81,95%CI=1.07-3.06) is a risk factor of breast cancer. Despite the menopausal status, the late age of first pregnancy(postmenopausal group:OR=3.01,95%CI=1.71-5.30; premenopausal group:OR=2.31,95%CI=1.35-3.98) is a risk factor of breast cancer, the breastfeeding (postmenopausal group:OR=0.45,95%CI=0.29-0.71; premenopausal group:OR=0.25,95%CI=0.16-0.41) is acted as a protective factor of breast cancer.Conclusion Our finding suggest that the family history of breast cancer, previous breast benign diseases, nulliparous women, prolonged the interval from giving first birth to menarche and accumulative menstrual years were the risk factors of breast cancer in Lanzhou city. Full term reproductive history and breastfeeding are protective factors of breast cancer. Health education, encouraging breastfeeding and having women with high risk factors of breast cancer to receive professional breast examination will reduce the incidence rate of breast cancer in Lanzhou.