Madigan M P, Ziegler R G, Benichou J, Byrne C, Hoover R N
Environmental Epidemiology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
J Natl Cancer Inst. 1995 Nov 15;87(22):1681-5. doi: 10.1093/jnci/87.22.1681.
Few estimates of the fraction of cases of breast cancer attributable to recognized risk factors have been published. All estimates are based on selected groups, making their generalizability to the U.S. population uncertain.
Our goal was to estimate the fraction of breast cancer cases in the United States attributable to well-established risk factors (i.e., later age at first birth, nulliparity, higher family income, and first-degree family history of breast cancer), using data from the first National Health and Nutrition Examination Survey (NHANES I) Epidemiologic Follow-up Study (NHEFS), the survey and follow-up of a probability sample of the U.S. population.
From a cohort of 7508 female participants surveyed in the early 1970s, and followed up between 1982 and 1984 and again in 1987, 193 breast cancer cases were accrued for study. We calculated incidence rates, relative risks (RRs), and population attributable risks (PARs) for breast cancer risk factors and extended our results to the U.S. female population by using sample weights from the NHANES I survey.
Our PAR estimates suggest that later age at first birth and nulliparity accounted for a large fraction of U.S. breast cancer cases, 29.5% (95% confidence interval [CI] = 5.6%-53.3%); higher income contributed 18.9% (95% CI = -4.3% to 42.1%), and family history of breast cancer accounted for 9.1% (95% CI = 3.0%-15.2%). Taken together, these well-established risk factors accounted for approximately 47% (95% CI = 17%-77%) of breast cancer cases in the NHEFS cohort and about 41% (95% CI = 2%-80%) in the U.S. population.
The RRs for most of these risk factors were modest, but their prevalence as a group was high, leading to estimates that suggest that a substantial proportion of breast cancer cases in the United States are explained by well-established risk factors.
Elucidation of the determinants underlying recognized factors and study of other factors that may confer risk or protection are needed in efforts to advance understanding of breast cancer etiology and to aid in devising strategies for prevention.
已发表的关于可归因于公认风险因素的乳腺癌病例比例的估计很少。所有估计均基于特定人群，其对美国人群的普遍适用性尚不确定。
我们的目标是利用首次全国健康与营养检查调查（NHANES I）流行病学随访研究（NHEFS）的数据，估计美国乳腺癌病例中可归因于已确定风险因素（即初产年龄较大、未生育、家庭收入较高以及乳腺癌一级家族史）的比例，该研究是对美国人群概率样本进行的调查和随访。
从20世纪70年代初接受调查的7508名女性参与者队列中，选取在1982年至1984年以及1987年再次进行随访期间确诊的193例乳腺癌病例进行研究。我们计算了乳腺癌风险因素的发病率、相对风险（RRs）和人群归因风险（PARs），并通过使用NHANES I调查的样本权重将结果推广至美国女性人群。
我们的PAR估计表明，初产年龄较大和未生育占美国乳腺癌病例的很大比例，为29.5%（95%置信区间[CI]=5.6%-53.3%）；较高收入占18.9%（95%CI=-4.3%至42.1%）；乳腺癌家族史占9.1%（95%CI=3.0%-15.2%）。总体而言，这些已确定的风险因素在NHEFS队列中占乳腺癌病例的约47%（95%CI=17%-77%），在美国人群中约占41%（95%CI=2%-80%）。
大多数这些风险因素的RRs适中，但作为一个群体其患病率较高，则估计表明美国相当一部分乳腺癌病例可由已确定的风险因素解释。
为了增进对乳腺癌病因的理解并有助于制定预防策略，需要阐明公认因素背后的决定因素，并研究其他可能带来风险或保护作用的因素。
