Case-control Study On The Risk Factors Of Breast Cancer In Jiashan County

Background and ObjectiveBreast cancer is one of the feminine most common malignant tumor, and the incident rate increases in majority national and local. Today breast cancer is the first common feminine malignant tumor in western developed countries. China is a nation with a relatively low incidence of breast cancer, but the incidence rate is increasing rapidly specially in some economical developed areas and cities. Although the trends of cancer occurred age advancing and mortality rate increasing are obvious, the etiology hasn't been known yet. The increasing of breast cancer rate implies the relation with the changes of risk factors and their exposure level. Therefore, the study on life style of special person, diet custom, hormone level, environmental factors and so on may provide scientific basis for further research on etiology and breast cancer preventing and controlling stragety.Jiashan County in Zhejiang Province is a rich rural area. Breast cancer is common and the incident rate has an increasing trend. What's more, the complete cancer registration and report system in Jiashan County builds a good foundation for our research. This research plans to use case-control study to find out the risk factors of feminine breast cancer in Jiashan County and their changes.Materials and MethodsThe case and control groups had an origin of a cancer cohort-study population in Jiashan County. After about 15 years follow-up, 84 survival individuals, who had been diagnosed with breast cancer during 1st May 1990 to May 2005, composed the case group in this analysis; 269 participants were random selected based on age form cohort population as health group. A constructed questionnaire elicited information on the demographic and socio-economic condition, diet, history of selected diseases, family cancer history, occupation and psychological factors. All subjects were interviewed face-to-face by trained interviewers. For each food, amounts consumed were estimated according to models of the more frequently consumed foods for the accuracy of survey. Unconditional Logistic Regression model for simple factors or multi-factors models was used. All analyses were performed with SPSS for Windows 13.0 and Excel 2000.ResultsUnivariate analysis showed that high level of education, non-agricultural job, fatty meat, pickled meat, pickled fish, salty eggs, fried fish, noodle, animal oil, white meat (≥1.2 Kg/Year) , Animal offal, fresh fish in river (2.4-4.8 Kg/Year) , fresh fish in sea, fresh crabs and shellfish, boiled eggs, fried soybean, soybean sauce , smoking, passive smoking family, the workplace passive smoking, passive smoking for more than 11 years, angry easily, history of benign breast disease and unnatural amenorrhea increased the risk of breast cancer. Proper intake of salt (3.6-9 Kg/Year) , health care products, happy usually, satisfaction with the status of the family, later age of menarche (≥15), more than four times of full-term births, more than four childrenbreastfeeding, breastfeeding for more than 36 months might reduce risk. Multiple regression analysis showed that non-farming, noodle, higher intake of fresh fish in river (2.4-4.8 Kg/Year) and soybean sauce, smoking, passive smoking for more than 11 years, angry easily and history of benign breast disease were the risk factors; Proper intake of salt (3.6-9 Kg/Year) , health products and more than four times of full-term births were protective factors.ConclusionThe study finds that non-agricultural, intake of noodle, higher intake of fresh fish in river, intake of soybean sauce, smoking, passive smoking a long time, angry easily and history of benign breast diseases are risk factors of breast cancer; Protective factors contain proper intake of salt and taking health care of products, and many times of full-term births. Thus the incidence of breast cancer is the result of multifactors. The promotion of healthy lifestyles, maintaining a good mood, diet habits, reducing pollution, benign breast disease screening, intake of health care foods are appropriate and effective measures to control and reduce the incidence of female breast cancer in Jiashan County.