Heineman E F, Zahm S H, McLaughlin J K, Vaught J B
Epidemiology and Biostatistics Program, National Cancer Institute, Rockville, MD 20852.
Int J Cancer. 1994 Dec 15;59(6):728-38. doi: 10.1002/ijc.2910590603.
To clarify the relationship between tobacco use and risk of colorectal cancer, we evaluated a cohort of 248,046 American veterans followed prospectively for 26 years. In comparison with veterans who had never used tobacco, the risk of death was significantly increased for colon cancer and rectal cancer among current and former cigarette smokers and among pipe or cigar smokers, controlling for social class and occupational physical activity. Rectal-cancer risk was also significantly elevated among users of chewing tobacco or snuff. For both sites, risk increased significantly with pack-years, earlier age at first use, and number of cigarettes. These results reinforce 2 recent reports of the association of cigarette smoking and colorectal cancer in men and women. Inconsistencies in the findings of earlier epidemiologic studies appear to be due in large part to differences in length of follow-up or in choice of controls. Studies with at least 20 years of follow-up or population-based controls have tended to find elevated risk with tobacco smoking, while those with shorter follow-up or hospital controls have not. This, plus the strength and consistency of the association of smoking and colon polyps, suggest that smoking may primarily affect an early stage in the development of colon cancer. If this association is causal, tobacco use may be responsible for 16% of colon-cancer and 22% of rectal-cancer deaths among these veterans.
为了阐明烟草使用与结直肠癌风险之间的关系，我们对一组248,046名美国退伍军人进行了前瞻性随访，为期26年。与从未使用过烟草的退伍军人相比，在控制了社会阶层和职业体力活动的情况下，当前和既往吸烟者以及烟斗或雪茄吸烟者患结肠癌和直肠癌的死亡风险显著增加。嚼烟或鼻烟使用者患直肠癌的风险也显著升高。对于这两个部位，风险均随着吸烟包年数、首次使用烟草的年龄以及吸烟数量的增加而显著上升。这些结果强化了最近两项关于男性和女性吸烟与结直肠癌关联的报告。早期流行病学研究结果的不一致性似乎在很大程度上归因于随访时间的差异或对照选择的不同。随访至少20年或采用基于人群对照的研究往往发现吸烟会增加风险，而随访时间较短或采用医院对照的研究则未发现此关联。这一点，再加上吸烟与结肠息肉关联的强度和一致性，表明吸烟可能主要影响结肠癌发展的早期阶段。如果这种关联是因果关系，那么在这些退伍军人中，烟草使用可能导致16%的结肠癌死亡和22%的直肠癌死亡。
