Tavani A, Gallus S, Negri E, Franceschi S, Talamini R, La Vecchia C
Istituto di Ricerche Farmacologiche Mario Negri, Milan, Milano, Italy.
Eur J Epidemiol. 1998 Oct;14(7):675-81. doi: 10.1023/a:1007545607059.
The relationship between smoking habit and risk of colon and rectal cancers was considered in a case-control study conducted between 1991 and 1996 in six Italian centers. Cases were 1225 patients below age 75 with histologically confirmed cancer of the colon and 728 with cancer of the rectum. Controls were 4154 patients admitted to hospital for a wide spectrum of acute, non-neoplastic diseases. Compared to neversmokers, the odds ratios (OR) for current smokers of 25 or more cigarettes/day was 0.90 for patients with colon and 0.86 for those with rectal cancer and those for ex-smokers were 1.02 and 1.09 for colon and rectal cancer, respectively. No increase in risk was found with duration of the habit, the OR for 40 or more years being 0.79 for colon and 0.87 for rectal cancer. Furthermore, no relationship was apparent with time since starting (the OR for 40 or more years were 0.94 for colon and 1.05 for rectal cancer), or age at starting (the OR for < 18 years were 1.02 for colon and 1.01 for rectal cancer), or for pack-years smoked (the OR for 40 or more pack-years were 0.93 for colon and 0.91 for rectal cancer) or time since stopping among ex-smokers. No increase in risk was found in smokers of > or = 15 cigarettes/day for 40 years or longer (OR: 0.93). No significant heterogeneity was found across strata of age at diagnosis, sex, education, physical activity at work, intake of alcohol, coffee, vegetables, total energy, and number of meals/day. Likewise, no significant association was apparent for various intestinal subsites. Thus, this study did not find cigarette smokers at higher risk for cancer of the bowel even after a long duration and a long period since starting.
1991年至1996年期间，在意大利的六个中心开展了一项病例对照研究，探讨吸烟习惯与结肠癌和直肠癌风险之间的关系。病例为1225名75岁以下经组织学确诊的结肠癌患者和728名直肠癌患者。对照为4154名因各种急性非肿瘤性疾病入院的患者。与从不吸烟者相比，每天吸烟25支及以上的现吸烟者患结肠癌的比值比（OR）为0.90，患直肠癌的比值比为0.86；既往吸烟者患结肠癌和直肠癌的比值比分别为1.02和1.09。未发现风险随吸烟习惯持续时间增加，吸烟40年及以上者患结肠癌的OR为0.79，患直肠癌的OR为0.87。此外，开始吸烟后的时间（吸烟40年及以上者患结肠癌的OR为0.94，患直肠癌的OR为1.05）、开始吸烟的年龄（<18岁开始吸烟者患结肠癌的OR为1.02，患直肠癌的OR为1.01）、吸烟包年数（吸烟40包年及以上者患结肠癌的OR为0.93，患直肠癌的OR为0.91）或既往吸烟者戒烟后的时间均未显示出明显关联。每天吸烟≥15支且持续40年或更长时间的吸烟者未发现风险增加（OR：0.93）。在诊断时的年龄、性别、教育程度、工作中的体力活动、酒精、咖啡、蔬菜摄入量、总能量和每日进餐次数等分层中未发现显著异质性。同样，在各个肠道亚部位也未发现明显的显著关联。因此，即使吸烟时间长且开始吸烟后经过很长时间，本研究也未发现吸烟者患肠癌的风险更高。
