Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China.
JNCI Cancer Spectr. 2022 Jan 5;6(1). doi: 10.1093/jncics/pkac005.
It remains unknown how cancer risks vary by duration of smoking cessation and whether the benefit is attenuated by postcessation weight gain.
We prospectively followed 198 565 persons from the Nurses' Health Study (1978-2016), Nurses' Health Study II (1991-2017), and Health Professionals Follow-up Study (1988-2016) who were free of cancer at baseline. We used proportional hazard Cox models to compare cancer risk between current smokers and former smokers with different durations of smoking cessation and postcessation weight gains.
During 4 718 199 person-years of follow-up, we identified 32 456 cases of total cancer. Compared with current smokers, the risks for total and smoking-related cancer in past smokers were reduced to the level similar to never smokers after abstaining smoking for more than 26 years, with the hazard ratio of 0.69 (95% confidence interval [CI] = 0.63 to 0.76) for total cancer and 0.31 (95% CI = 0.26 to 0.37) for smoking-related cancer, whereas no risk reduction was found for obesity-related cancer. Comparing former smokers with current smokers, the multivariable-adjusted hazard ratios for postcessation weight gain of 0-4.9 kg, 5-9.9 kg, and 10 kg or higher were 0.85 (95% CI = 0.81 to 0.89), 0.88 (95% CI = 0.83 to 0.93), and 0.93 (95% CI = 0.88 to 1.00) for total cancer and 0.62 (95% CI = 0.58 to 0.67), 0.65 (95% CI = 0.60 to 0.71), and 0.71 (95% CI = 0.65 to 0.78) for total smoking-related cancer. In contrast, higher weight gain following smoking cessation was associated with a modest increased obesity-related cancer risk.
Smoking cessation overall has a strong net association with lower risk of total cancer irrespective of weight gain. However, this inverse association may be attenuated by substantial postcessation weight gain, largely because of an increased risk of obesity-related cancers.
目前尚不清楚癌症风险随戒烟持续时间的变化情况，以及戒烟后体重增加是否会减弱这种益处。
我们前瞻性地随访了来自护士健康研究（1978-2016 年）、护士健康研究 II（1991-2017 年）和健康专业人员随访研究（1988-2016 年）的 198565 名基线时无癌症的人员。我们使用比例风险 Cox 模型比较了当前吸烟者与不同戒烟持续时间和戒烟后体重增加的前吸烟者之间的癌症风险。
在 4718199 人年的随访期间，我们共发现 32456 例癌症病例。与当前吸烟者相比，戒烟 26 年以上的既往吸烟者的总癌症和与吸烟相关的癌症风险降低至与从不吸烟者相似的水平，总癌症的风险比为 0.69（95%置信区间[CI]为 0.63 至 0.76），与吸烟相关的癌症为 0.31（95%CI=0.26 至 0.37），而肥胖相关的癌症则没有风险降低。与当前吸烟者相比，戒烟后体重增加 0-4.9kg、5-9.9kg 和 10kg 或以上的多变量校正风险比分别为 0.85（95%CI=0.81 至 0.89）、0.88（95%CI=0.83 至 0.93）和 0.93（95%CI=0.88 至 1.00），总癌症为 0.62（95%CI=0.58 至 0.67）、0.65（95%CI=0.60 至 0.71）和 0.71（95%CI=0.65 至 0.78）。相比之下，戒烟后体重增加与肥胖相关的癌症风险适度增加有关。
总体而言，戒烟与总癌症风险降低有很强的净关联，而不论体重增加与否。然而，这种负相关可能会因戒烟后体重显著增加而减弱，这主要是由于肥胖相关癌症的风险增加所致。
