Halpern M T, Gillespie B W, Warner K E
Department of Public Health Policy and Administration, School of Public Health, University of Michigan, Ann Arbor 48109-2029.
J Natl Cancer Inst. 1993 Mar 17;85(6):457-64. doi: 10.1093/jnci/85.6.457.
It is well known that the relative risk (RR) of lung cancer mortality decreases following smoking cessation compared with the risk in persons who continue to smoke. However, changes in the absolute risk of lung cancer death following smoking cessation are not well documented. Further, few studies have examined the effect of age at smoking cessation on subsequent lung cancer death risk.
The purpose of this study was to examine and compare absolute and relative lung cancer death risks in former smokers as a function of age at cessation.
Using the American Cancer Society's Cancer Prevention Study II, a prospective cohort study with 6 years of follow-up, we modeled absolute risk of lung cancer mortality in individuals who had never smoked and in current and former smokers. The model was fit with the use of person-years logistic regression analysis.
Similar patterns of absolute risk of lung cancer death by age were found for all ages of smoking cessation up to the mid-60s. Lower lung cancer death risk was observed for those quitting earlier in life, and the risk for all former smokers was significantly lower than that for current smokers. For those quitting between ages 30 and 49, lung cancer death risk rose gradually with age at a rate slightly greater than that for those who had never smoked. Lung cancer death risk for former smokers quitting between ages 50 and 64 leveled off near the risk attained at the time of quitting until around age 75, when it rose sharply. At age 75, the RR for former smokers compared with current smokers was approximately 45% for those quitting in their early 60s, approximately 20% for those quitting in their early 50s, and less than 10% for those quitting in their 30s. For those who had never smoked, the RR at age 75 is less than 5%.
In terms of reduced risk of lung cancer mortality, smoking cessation is beneficial at any age, with much greater benefits accruing to those quitting at younger ages. Unlike previous research, which has primarily examined the effects of cessation as a function of years since quitting, our results demonstrate that age at cessation has a major impact on subsequent lung cancer risks.
Smokers of all ages should be encouraged to quit because cessation at any age decreases lung cancer risk relative to that of current smokers.
众所周知，与继续吸烟的人相比，戒烟后肺癌死亡的相对风险（RR）会降低。然而，戒烟后肺癌死亡绝对风险的变化尚无充分记录。此外，很少有研究考察戒烟年龄对后续肺癌死亡风险的影响。
本研究的目的是考察并比较不同戒烟年龄的既往吸烟者的肺癌死亡绝对风险和相对风险。
利用美国癌症协会的癌症预防研究II（一项有6年随访的前瞻性队列研究），我们对从不吸烟的个体以及当前吸烟者和既往吸烟者的肺癌死亡绝对风险进行了建模。该模型采用人年逻辑回归分析进行拟合。
在60多岁中期之前的所有戒烟年龄中，按年龄划分的肺癌死亡绝对风险模式相似。在生命早期戒烟者的肺癌死亡风险较低，所有既往吸烟者的风险显著低于当前吸烟者。对于30至49岁戒烟者，肺癌死亡风险随年龄逐渐上升，上升速度略高于从不吸烟者。50至64岁戒烟的既往吸烟者的肺癌死亡风险在接近戒烟时达到的风险水平保持平稳，直到75岁左右，此时风险急剧上升。在75岁时，与当前吸烟者相比，60岁出头戒烟者的RR约为45%，50岁出头戒烟者约为20%，30多岁戒烟者则不到10%。对于从不吸烟的人，75岁时的RR小于5%。
就降低肺癌死亡风险而言，任何年龄戒烟都是有益的，年轻时戒烟获益更大。与以往主要考察戒烟后年限对戒烟效果影响的研究不同，我们的结果表明，戒烟年龄对后续肺癌风险有重大影响。
应鼓励所有年龄段的吸烟者戒烟，因为任何年龄戒烟相对于当前吸烟者而言都能降低肺癌风险。
