Background Reducing cigarettes/day may lower the risk of lung cancer compared with continuing to smoke at the same intensity. Other changes in smoking behaviors, such as increasing cigarette consumption or quitting for a period and relapsing, may also affect lung cancer risk. Methods We examined changes in smoking status and cigarettes/day among 24,613 Finnish male smokers aged 50-69 years who participated in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study. Longitudinal data on smoking were collected during study follow-up visits three times a year (approximately every 4 months) between 1985 and 1993. Incident lung cancer cases through 2012 were identified by the Finnish Cancer Registry. Risk ratios (RRs) and 95% confidence intervals (95%CI) were estimated using Cox proportional hazards regression. Results Compared with smoking 20 cigarettes/day continuously across the intervention period, reducing an average of 5 cigarettes/day per year while smoking was associated with a 20% lower risk of lung cancer (95%CI : 0.71 to 0.90). A substantially lower risk of lung cancer was also observed when participants smoked at 50% (RR = 0.72; 95%CI : 0.57-0.90) and 10% (RR = 0.55; 95%CI : 0.36-0.83) of study visits, relative to smoked at 100% of study visits. Conclusions Smokers may lower their risk of lung cancer by reducing smoking intensity (cigarettes per day while smoking) and the time they smoke. However, quitting smoking completely is the most effective way for smokers to reduce their risk of lung cancer.

中文翻译：

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ATBC 研究中吸烟情况的变化和随后的肺癌风险


背景 与继续以相同强度吸烟相比，减少每天吸烟量可能会降低患肺癌的风险。吸烟行为的其他变化，例如增加吸烟量或戒烟一段时间后又复发，也可能会影响肺癌风险。方法 我们检查了参加α-生育酚、β-胡萝卜素癌症预防 (ATBC) 研究的 24,613 名 50-69 岁芬兰男性吸烟者的吸烟状况和每天吸烟量的变化。 1985 年至 1993 年间，每年 3 次（大约每 4 个月）的研究随访期间收集了有关吸烟的纵向数据。芬兰癌症登记处确定了 2012 年为止的肺癌病例。使用 Cox 比例风险回归估计风险比 (RR) 和 95% 置信区间 (95%CI)。结果 与在干预期间每天连续吸 20 支烟相比，每年平均减少 5 支烟/天，而吸烟与肺癌风险降低 20% 相关（95% CI：0.71 至 0.90）。当参与者在研究访问中吸烟率为 50%（RR = 0.72；95%CI：0.57-0.90）和 10%（RR = 0.55；95%CI：0.36-0.83）时，肺癌风险也显着降低，相对100% 的研究访问中吸烟。结论 吸烟者可以通过减少吸烟强度（吸烟时每天吸烟支数）和吸烟时间来降低患肺癌的风险。然而，完全戒烟是吸烟者降低肺癌风险最有效的方法。