McCredie M R, Dite G S, Giles G G, Hopper J L
Cancer Epidemiology Research Unit, New South Wales Cancer Council, Sydney, Australia.
Cancer Causes Control. 1998 Mar;9(2):189-98. doi: 10.1023/a:1008886328352.
A case-control-family study of breast cancer in women under the age of 40 was carried out in Melbourne and Sydney, Australia, from 1992 to 1995 to determine the risk factors for these women. Subjects included 467 incident cases identified by state cancer registries and 408 population-based controls.
All participants completed a structured risk-factor questionnaire and family pedigree during an in-person interview. Where possible, cancers in first- and second-degree relatives were verified.
Multiple logistic regression analysis showed that the strongest risk factor for breast cancer was a family history of the disease -- having at least one affected first-degree relative trebled the risk (relative risk [RR] = 3.3, 95 percent confidence interval [CI] = 1.9-5.8). Risk increased with height by three percent (standard error [SE] of one percent) per cm, and after adjusting for height, there was evidence for a decreased risk in women weighing 73 kg or more. There was an increased risk of breast cancer after the first full-term birth (RR = 1.8, CI = 1.0-3.5) but this risk fell by 30 percent (SE = 11 percent) with each subsequent livebirth.
The effects of other reproductive factors and oral contraceptive use, although not nominally significant, were in accord with published findings from similar studies in young women. This study of Australian women has indicated that some risk factors for breast cancer in women under age 40 differ from those reported for older women either in direction (e.g., weight) or relative importance (e.g., family history).
1992年至1995年在澳大利亚墨尔本和悉尼开展了一项针对40岁以下女性乳腺癌的病例对照家系研究，以确定这些女性的风险因素。研究对象包括由州癌症登记处确定的467例新发病例和408例基于人群的对照。
所有参与者在面对面访谈中完成了一份结构化的风险因素问卷和家系图。尽可能核实一级和二级亲属中的癌症情况。
多因素logistic回归分析显示，乳腺癌最强的风险因素是该病的家族史——有至少一位受影响的一级亲属会使风险增加两倍（相对风险[RR]=3.3，95%置信区间[CI]=1.9 - 5.8）。风险随身高每增加1厘米而增加3%（标准误[SE]为1%），在调整身高后，有证据表明体重73千克及以上的女性风险降低。首次足月分娩后患乳腺癌的风险增加（RR = 1.8，CI = 1.0 - 3.5），但随后每一次活产，该风险会降低30%（SE = 11%）。
其他生殖因素和口服避孕药使用的影响虽然名义上不显著，但与年轻女性类似研究已发表的结果一致。这项对澳大利亚女性的研究表明，40岁以下女性乳腺癌的一些风险因素在方向（如体重）或相对重要性（如家族史）方面与老年女性报告的不同。
