中国六城市女性生理生育因素与乳腺癌关系的病例对照研究

目的研究城市女性乳腺癌的危险因素，探讨城市女性生理生育因素的变化与城市女性乳腺癌发病的关联强度，促进乳腺癌的预防和控制。方法采用病例对照的研究方法，新发病例通过北京、天津、上海、重庆、武汉、广州六城市的乳腺癌监测点确定，对照从当地正常人群数据库中随机抽样，对收集到3332对1：1年龄配对的病例和对照进行问卷调查。通过条件Logistic模型进行相对危险度及剂量-反应效应估计。结果在调整年龄、职业、饮食等因素后，城市女性中乳腺癌发病的危险因素为初潮年龄的提前（≤14岁，OR=1.37，95％CI=1.12－1.66）、月经持续天数长（〉7天，OR=1.18，95％ CI=1.00－1.38）、有痛经（OR=1.21，95％ CI=1.03－1.42）、结婚晚（≥28岁，OR：2.13，95％ CI=1.63－2.79）、首次怀孕晚（≥30岁，OR=2.13，95％CI=1.63－2.79）等，而保护性因素有月经间隔天数长（ 〉28天，OR=0.81，95％ CI=0.68－0.95）、绝经年龄早（≤45岁，OR=0.58，95％ CI=0.47－0.72）、怀孕次数多（≥2次，OR=0.67，95％ CI=0.45－0.99），哺乳（≥4个月，OR=0.70，95％CI：0.60－0.83）。结论女性生理生育因素是影响城市女性乳腺癌发病的主要危险因素，可部分解释中国城市女性乳腺癌呈逐年上升趋势的原因。

Relationship between reproductive factors and breast cancer for women in six cities of China: a case-control study

Objective To study risk factors of breast cancer among urban women, and to explore the association between reproductive factors and breast cancer in order to control and prevent breast cancer among urban women in China. Methods A population-based case-control study was conducted in six cities including Beijing, Tianjin, Shanghai, Chongqing, Wuhan, and Guangzhou which were chosen as the sample areas. 3332 case with 1：1 matched controls were interviewed with a uniformed questionnaire. Conditional Logistic regression model was applied to estimate the association and the effect of dose-reaction between risk factors and the breast cancer for single and multivariate analysis. Results After adjustment for age, occupation, dieting and some other factors, the risk factors for the breast cancer among urban women included early age at menarche （≤14 years old, OR = 1.37, 95% CI= 1.12 - 1.66）, the days of menstruation （ 〉7 days, OR =1.18, 95% CI=1.00-1.38）, dysmenorrheal （OR =1.21, 95% CI=1.03 -1.42）, old age at marriage （≥28 years old, OR =2. 13, 95% CI=1.63-2.79）, late pregnancy （≥30 years old, OR =2.13, 95% CI=1.63-2.79）. The protection factors included the interval days of menstruation （ 〉28 days, OR =0.81, 95% CI=0.68-0.95）, early menopuase （≤45 years old, OR =0.58, 95% CI=0.47 -0.72）, number of pregnancy and birth （≥2, OR =0.67, 95% CI =0.45-0.99）, lactation （≥4 months, OR=0.70, 95% CI=0.60-0.83）. Conclusion The reproductive factors play independently an important role and can partly explain the rapid rising of breast cancer among Chinese urban women.