Risch H A, Howe G R
Department of Epidemiology and Public Health, Yale University School of Medicine, New Haven, CT 06510.
Am J Epidemiol. 1994 Apr 1;139(7):670-83. doi: 10.1093/oxfordjournals.aje.a117057.
The association between the occurrence of carcinoma of the breast and previous usage of menopausal estrogens, progestins, and oral contraceptives is examined in a record-linkage study using the Saskatchewan Health Prescription-Drug-Plan Database. Saskatchewan Health is a governmental agency that funds publicly insured health care for essentially all residents of the province. For this study, all women aged 43-49 years in 1976 resident in Saskatchewan were identified from the Saskatchewan Health master registration file. These women were linked by registration beneficiary number to the Drug-Plan Database for the period from January 1976 to June 1987 and to the Provincial Cancer Registry Database for the period from March 1960 to December 1990. The fact and date of death or emigration from the province were obtained through the annual updates of the health plan. Of the 33,003 women initially in the cohort, 213 had a breast cancer diagnosed before 1976 and were omitted from this analysis. Between 1976 and 1990, 742 new primary breast cancer cases occurred. Women taking estrogens unopposed by progestins had an elevated risk of breast cancer, the risk increasing by 7% (relative risk = 1.072, 95% confidence interval 1.02-1.13; p = 0.008) for each 252 tablets used (approximately 1 year of use). Usage of estrogens opposed by progestins showed no association with risk (p = 0.48). Women taking oral contraceptives during this follow-up period also had a higher risk, increasing by 14% (relative risk = 1.144, 95% confidence interval 1.05-1.24; p = 0.002) for every 252 tablets used. These 1-year risk elevations are small but become appreciable at longer durations. For example, at 5 years of unopposed estrogen use, the relative risk is 1.42; for 5 years of oral contraceptive use, it is 1.96.
利用萨斯喀彻温省健康处方药物计划数据库，通过一项记录链接研究，对乳腺癌发病与既往使用绝经后雌激素、孕激素及口服避孕药之间的关联进行了调查。萨斯喀彻温省健康局是一个政府机构，为该省基本上所有居民的公共保险医疗保健提供资金。在本研究中，从萨斯喀彻温省健康局主登记档案中识别出1976年居住在萨斯喀彻温省、年龄在43 - 49岁的所有女性。这些女性通过登记受益号码与1976年1月至1987年6月期间的药物计划数据库以及1960年3月至1990年12月期间的省级癌症登记数据库建立了关联。通过健康计划的年度更新获取死亡或离开该省的事实及日期。在最初纳入队列的33,003名女性中，有213名在1976年之前被诊断出患有乳腺癌，被排除在本分析之外。在1976年至1990年期间，出现了742例新的原发性乳腺癌病例。单独使用雌激素的女性患乳腺癌的风险升高，每使用252片（约1年用量），风险增加7%（相对风险 = 1.072，95%置信区间1.02 - 1.13；p = 0.008）。使用雌激素加用孕激素与风险无关联（p = 0.48）。在此随访期间服用口服避孕药的女性风险也较高，每使用252片，风险增加14%（相对风险 = 1.144，95%置信区间1.05 - 1.24；p = 0.002）。这些1年的风险升高幅度较小，但在更长时间使用时会变得明显。例如，单独使用雌激素5年时，相对风险为1.42；使用口服避孕药5年时，相对风险为1.96。
