11月2日,《美国医学会杂志》上的一则研究披露，每周饮3至6杯酒精性饮料与乳腺癌风险的小幅增加有关，而在早期和后期成年阶段饮酒也都与该风险的增加有关。
根据文章的背景资料：“许多研究显示，较多地饮用酒精性饮料与乳腺癌风险的增加有关系。然而，在美国常见的少量饮酒的影响一直没有得到良好的量化。此外，人们对饮酒模式（如饮酒的频度及‘狂饮’）以及在成年后的不同时期饮酒所起的作用也不甚了解。”
波士顿布里格姆及妇女医院和哈佛医学院的Wendy Y. Chen, M.D., M.P.H.及其同事对乳腺癌与成年时饮酒之间的关系进行了检查，其中包括饮酒的量、频度及饮酒的年龄。这项研究包括了10万又5986位参加护士健康研究的妇女，对她们所做的追踪有成年早期的饮酒评估以及8项更新的饮酒评估，时间是从1980年直到2008年。研究人员所测定的初步结果为发生浸润性乳腺癌的风险。
在随访期间，该研究的参与者中有7690人被诊断罹患浸润性乳腺癌。数据分析表明，低度饮酒（每天酒精摄入量5.0 至 9.9克，相当于每周饮酒3-6玻璃杯）与乳腺癌风险增加15%有关，这种相关度虽小但却有统计学上的显著性。另外，平均每日摄入至少30克酒精（每日至少2杯酒）的女性与从来不饮酒的妇女相比，其罹患乳腺癌的风险增加了51%。
研究人员还发现，当单独检测时，在18至40岁期间及在40岁后的饮酒水平都与罹患乳腺癌的风险具有很强的相关性。在成年早期饮酒与乳腺癌的相关性甚至会持续到在40岁后开始控制酒精摄入之后。
在对累积酒精摄入量进行校正之后，狂饮但非频繁性饮酒也与罹患乳腺癌风险的增加有关。
文章的作者补充说，虽然饮酒与乳腺癌之间的关联的确切机制尚不清楚，但一个可能的解释也许涉及到酒精对循环雌激素水平的影响。
研究人员写道：“总之，我们在一个大型的前瞻性群组研究中对酒精摄入的时间、频度、数量及饮酒的类型与乳腺癌风险之间的关系提供了一个全面的评估。该研究含有乳腺癌风险因子的详细资讯。我们的结果凸显了在评估酒精以及其它可能对致癌过程有影响的饮食因子时，需要考虑一生中对这些因子的接触总体重要性。然而，个人则需要对轻度至中度饮酒会有发生乳腺癌的少量风险以及其对心血管疾病所具有的有利影响进行斟酌以做出有关饮酒的最佳的个人选择。”(生物谷 Bioon.com)
doi:10.1001/jama.2011.1590
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Moderate Alcohol Consumption During Adult Life, Drinking Patterns, and Breast Cancer Risk
Wendy Y. Chen, MD, MPH; Bernard Rosner, PhD; Susan E. Hankinson, ScD; Graham A. Colditz, MD, DrPH; Walter C. Willett, MD, DrPH
Context Multiple studies have linked alcohol consumption to breast cancer risk, but the risk of lower levels of consumption has not been well quantified. In addition, the role of drinking patterns (ie, frequency of drinking and “binge” drinking) and consumption at different times of adult life are not well understood.
Objective To evaluate the association of breast cancer with alcohol consumption during adult life, including quantity, frequency, and age at consumption.
Design, Setting, and Participants Prospective observational study of 105 986 women enrolled in the Nurses' Health Study followed up from 1980 until 2008 with an early adult alcohol assessment and 8 updated alcohol assessments.
Main Outcome Measures Relative risks of developing invasive breast cancer.
Results During 2.4 million person-years of follow-up, 7690 cases of invasive breast cancer were diagnosed. Increasing alcohol consumption was associated with increased breast cancer risk that was statistically significant at levels as low as 5.0 to 9.9 g per day, equivalent to 3 to 6 drinks per week (relative risk, 1.15; 95% CI, 1.06-1.24; 333 cases/100 000 person-years). Binge drinking, but not frequency of drinking, was associated with breast cancer risk after controlling for cumulative alcohol intake. Alcohol intake both earlier and later in adult life was independently associated with risk.
Conclusions Low levels of alcohol consumption were associated with a small increase in breast cancer risk, with the most consistent measure being cumulative alcohol intake throughout adult life. Alcohol intake both earlier and later in adult life was independently associated with risk.
