Reduction in total and major cause-specific mortality from tobacco smoking cessation: a pooled analysis of 16 population-based cohort studies in Asia

Impact of smoking cessation duration on lung cancer mortality: A systematic review and meta-analysis

BACKGROUND

Smoking history is a heterogeneous situation for different populations, and numerous studies suggest that smoking cessation is conducive to reduce the mortality of lung cancer. However, no quantitative meta-analysis regarding smoking cessation duration based on different populations has demonstrated it clearly.

METHODS

We systematically searched four electronic databases (PubMed, Embase, the Cochrane Central Register of Controlled Trials, and Scoups) till February 2023. Eligible studies reported the association between lung cancer survival and duration of smoking cessation. Additionally, we stratified the study population according to whether they had lung cancer at the time they quit smoking. Studies were pooled with the random-effects model.

RESULTS

Out of the 11,361 potential studies initially identified, we included 24 studies involving 969,560 individuals in our analysis. Lung cancer mortality varied across two groups: general quitters and peri-diagnosis quitters. For general quitters, those who had quit smoking for less than 10 years exhibited an RR of 0.64 (95% CI [0.55-0.76]), while those who quit for 10-20 years had an RR of 0.33 (0.25-0.43), over 20 years had an RR of 0.16 (0.11-0.24), and never-smokers had an RR at 0.11 (0.07-0.15). Among peri-diagnosis quitters, the 1-year Overall Survival (OS) showed an RR of 0.80 (0.67-0.96), the 2-year OS had an RR of 0.89 (0.80-0.98), the 3-year OS had an RR of 0.93 (0.84-1.03), and the 5-year OS had an RR of 0.85 (0.76-0.96).

CONCLUSIONS

Earlier and longer smoking cessation is associated with reduced lung cancer mortality, no matter in which cessation stage for two different populations.

Prevalence and risk factors of colorectal neoplasia in individuals aged 40-49 years: Findings from screening program in China

BACKGROUND AND AIM

The incidence of colorectal cancer (CRC) in individuals under 50 is increasing worldwide. We conducted an analysis of colonoscopy findings in high-risk individuals under 50 in the CRC screening program in Tianjin, China, to determine the detection rate and risk factors of advanced adenomas (AA), advanced colorectal neoplasia (ACN), colorectal neoplasia (CN).

METHODS

Our study investigated individuals aged 40-49 who underwent CRC screening and completed colonoscopy, 2012-2020, while the 50-54 age group served as a control. We compared the detection rates of AA, ACN, and CN among three age groups using univariate and multivariable logistic regression analyses, and investigated the risk factors associated with AA, ACN, and CN among individuals aged 40-49.

RESULTS

We found a gradual increase in the detection rate of AA, ACN, and CN among individuals aged 40-54. The detection rates for AA (OR 0.58; 95% CI 0.41-0.81), ACN (OR 0.58; 95% CI 0.43-0.77), and CN (OR 0.64; 95% CI 0.56-0.74) were lower in individuals aged 40-44 compared to 45-49. The detection rates of AA (OR 1.08; 95% CI 0.87-1.34) and ACN (OR 1.12; 95% CI 0.93-1.35) in individuals aged 45-49 were comparable with 50-54. Besides, lifestyle factors, BMI, and FIT are not associated with the detection rates of AA, ACN, and CN among individuals aged 40-49.

CONCLUSIONS

Our study reveals screening data in individuals under 50, indicating comparable detection rates of AA and ACN in individuals aged 45-49 and 50-54. These findings provide valuable data support for optimizing the optimal age to initiate screening.

Lung Cancer Risk Prediction Models for Asian Ever-Smokers

INTRODUCTION

Although lung cancer prediction models are widely used to support risk-based screening, their performance outside Western populations remains uncertain. This study aims to evaluate the performance of 11 existing risk prediction models in multiple Asian populations and to refit prediction models for Asians.

METHODS

In a pooled analysis of 186,458 Asian ever-smokers from 19 prospective cohorts, we assessed calibration (expected-to-observed ratio) and discrimination (area under the receiver operating characteristic curve [AUC]) for each model. In addition, we developed the "Shanghai models" to better refine risk models for Asians on the basis of two well-characterized population-based prospective cohorts and externally validated them in other Asian cohorts.

RESULTS

Among the 11 models, the Lung Cancer Death Risk Assessment Tool yielded the highest AUC (AUC [95% confidence interval (CI)] = 0.71 [0.67-0.74] for lung cancer death and 0.69 [0.67-0.72] for lung cancer incidence) and the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial Model had good calibration overall (expected-to-observed ratio [95% CI] = 1.06 [0.90-1.25]). Nevertheless, these models substantially underestimated lung cancer risk among Asians who reported less than 10 smoking pack-years or stopped smoking more than or equal to 20 years ago. The Shanghai models were found to have marginal improvement overall in discrimination (AUC [95% CI] = 0.72 [0.69-0.74] for lung cancer death and 0.70 [0.67-0.72] for lung cancer incidence) but consistently outperformed the selected Western models among low-intensity smokers and long-term quitters.

CONCLUSIONS

The Shanghai models had comparable performance overall to the best existing models, but they improved much in predicting the lung cancer risk of low-intensity smokers and long-term quitters in Asia.

Tooth loss mediates the association between smoking and an increased risk of dementia among older adults: The JAGES prospective cohort study

AIM

Tooth loss has various causes; however, its cause-specific effects on health outcomes remain unclear. This study evaluated whether the association between past/current smoking and risk of dementia was mediated by tooth loss.

MATERIALS AND METHODS

This 9-year-follow-up prospective cohort study targeted adults aged ≥65 years. Dementia incidence during 2013-2019, smoking status (never, past/current) in 2010 and the number of remaining teeth (≤19, ≥20) in 2013 were the outcome, exposure and mediator, respectively. We used causal mediation analysis to fit the Cox proportional hazards model and estimated the hazard ratio (HR) and 95% confidence interval (CI) of the natural indirect effect (NIE) of smoking on dementia incidence through tooth loss and their mediated proportions.

RESULTS

Among 32,986 participants (mean age 72.6 years [1 SD = 5.4]; men 48.4%), the dementia incidence during follow-up was 2.11/100 person-years. Tooth loss significantly mediated the association between past/current smoking and dementia incidence; the NIE of fewer remaining teeth for past/current smokers compared to never smokers was HR = 1.03 (95% CI: 1.02-1.05), and the mediated proportion was 18.0%.

CONCLUSIONS

Tooth loss significantly mediates the association between past/current smoking and an increased risk of dementia among older adults.

Association of the age at smoking initiation and cessation on all-cause and cause-specific mortality: The Japan Collaborative Cohort Study

We estimated the association between the age at smoking initiation and cessation and all-cause and cause-specific mortality among Japanese men (n = 41,711; age 40-79 years) by analyzing data from the Japan Collaborative Cohort Study for the Evaluation of Cancer Risks. From 1988 and 1990 to 2009, 13,429 all-cause deaths (cancers, n = 4999; cardiovascular diseases, n = 3682) occurred in this cohort. Fitted Cox proportional hazard models, with never smokers as the reference group, were created. Former smokers demonstrated a lower risk for all-cause and cause-specific mortality than current smokers, with a dose-dependent reduction in the risk based on smoking-initiation age. Among former smokers who quit smoking aged 50 years or more, the highest hazard ratios were detected for those who started smoking at <20 years of age (all-cause, cancer, and cardiovascular disease mortality, hazard ratio [95% confidence interval] 1.51 [1.29-1.77], 1.68 [1.27-2.23], and 1.48 [1.12-1.96], respectively). Former smokers who quit smoking at <50 years of age had negligible all-cause or cardiovascular disease mortality regardless of the smoking-initiation age, whereas the cancer mortality risk remained significantly high among those who quit smoking at 40-49 years of age. Thus, smoking cessation significantly reduces the all-cause mortality risk; however, early initiation and later cessation do not provide a huge benefit, which earlier cessation does. Therefore, all smokers should be encouraged to quit smoking earlier in life regardless of their age at smoking initiation.

Current and recent cigarette smoking in relation to cardiovascular and non-cardiovascular mortality in an elderly male Chinese population

OBJECTIVE

To investigate the association between current and former smoking and the risk of mortality in elderly Chinese men.

METHODS

Our study participants were elderly (≥ 60 years) men recruited in a suburban town of Shanghai. Cigarette smoking status was categorized as never smoking, remote (cessation > 5 years) and recent former smoking (cessation ≤ 5 years), and light-to-moderate (≤ 20 cigarettes/day) and heavy current smoking (> 20 cigarettes/day). Cox proportional hazards models and restricted cubic splines were used to examine the associations of interest.

RESULTS

The 1568 participants had a mean age of 68.6 ± 7.1 years. Of all participants, 311 were never smokers, 201 were remote former smokers, 133 were recent former smokers, 783 were light-to-moderate current smokers and 140 were heavy current smokers. During a median follow-up of 7.9 years, all-cause, cardiovascular and non-cardiovascular deaths occurred in 267, 106 and 161 participants, respectively. Heavy current smokers had the highest risk of all-cause and non-cardiovascular mortality, with an adjusted hazard ratio (HR) of 2.30 (95% CI: 1.34-4.07) and 3.98 (95% CI: 2.03-7.83) versus never smokers, respectively. Recent former smokers also had a higher risk of all-cause (HR = 1.62, 95% CI: 1.04-2.52) and non-cardiovascular mortality (HR = 2.40, 95% CI: 1.32-4.37) than never smokers. Cox regression restricted cubic spline models showed the highest risk of all-cause and non-cardiovascular mortality within 5 years of smoking cessation and decline thereafter. Further subgroup analyses showed interaction between smoking status and pulse rate (≥ 70 beats/min vs. < 70 beats/min) in relation to the risk of all-cause and non-cardiovascular mortality, with a higher risk in current versus never smokers in those participants with a pulse rate below 70 beats/min.

CONCLUSIONS

Cigarette smoking in elderly Chinese confers significant risks of mortality, especially when recent former smoking is considered together with current smoking.

Smoking cessation after diagnosis of COPD is associated with lower all-cause and cause-specific mortality: a nationwide population-based cohort study of South Korean men

BACKGROUND

The most effective way to halt the advancement of COPD is smoking cessation. However, limited data are available on the question of whether quitting smoking within two years after COPD diagnosis reduces the risk of mortality. The goal of our research was to analyze the relationship between quitting smoking after COPD diagnosis and the risks of all-cause and cause-specific mortality, using the Korean National Health Insurance Service (NHIS) database.

METHODS

This study included 1,740 male COPD patients aged 40 years or more who had been newly diagnosed within the 2003-2014 time period and had smoked prior to their COPD diagnosis. The patients were categorized into two groups according to their smoking status after COPD diagnosis: (i) persistent smokers (ii) quitters (smoking cessation within two years of COPD diagnosis). Multivariate Cox proportional hazard regression was performed to determine the adjusted hazard ratio (HR) and 95% confidence interval (CI) for both all-cause and cause-specific mortality.

RESULTS

Among 1,740 patients (mean age, 64.6 years; mean follow-up duration, 7.6 years), 30.5% stopped smoking after COPD diagnosis. Quitters gained a 17% risk reduction in all-cause mortality (aHR, 0.83; 95% CI, 0.69-1.00) and a 44% risk reduction in cardiovascular mortality (aHR, 0.56; 95% CI, 0.33-0.95) compared with persistent smokers.

CONCLUSION

Our study found that patients who quit smoking within two years after COPD diagnosis had lower risks of all-cause and cardiovascular mortality relative to persistent smokers. These results can be used to encourage newly diagnosed COPD patients to stop smoking.

The effectiveness of smartphone application-based interventions for assisting smoking cessation: A systematic review and meta-analysis (Preprint)

BACKGROUND

Smoking is a leading cause of premature death globally. Quitting smoking reduces the risk of all-cause mortality by 11%-34%. Smartphone app-based smoking cessation (SASC) interventions have been developed and are widely used. However, the evidence for the effectiveness of smartphone-based interventions for smoking cessation is currently equivocal.

OBJECTIVE

The purpose of this study was to synthesize the evidence for the effectiveness of smartphone app-based interventions for smoking cessation.

METHODS

We conducted a systematic review and meta-analysis of the effectiveness of smartphone interventions for smoking cessation based on the Cochrane methodology. An electronic literature search was performed using the Cochrane Library, Web of Science, PubMed, Embase, PsycINFO, China National Knowledge Infrastructure, and Wanfang databases to identify published papers in English or Chinese (there was no time limit regarding the publication date). The outcome was the smoking abstinence rate, which was either a 7-day point prevalence abstinence rate or a continuous abstinence rate.

RESULTS

A total of 9 randomized controlled trials involving 12,967 adults were selected for the final analysis. The selected studies from 6 countries (the United States, Spain, France, Switzerland, Canada, and Japan) were included in the meta-analysis between 2018 and 2022. Pooled effect sizes (across all follow-up time points) revealed no difference between the smartphone app group and the comparators (standard care, SMS text messaging intervention, web-based intervention, smoking cessation counseling, or apps as placebos without real function; odds ratio [OR] 1.25, 95% CI 0.99-1.56, P=.06, I²=73.6%). Based on the subanalyses, 6 trials comparing smartphone app interventions to comparator interventions reported no significant differences in effectiveness (OR 1.03, 95% CI 0.85-1.26, P=.74, I²=57.1%). However, the 3 trials that evaluated the combination of smartphone interventions combined with pharmacotherapy compared to pharmacotherapy alone found higher smoking abstinence rates in the combined intervention (OR 1.79, 95% CI 1.38-2.33, P=.74, I²=7.4%). All SASC interventions with higher levels of adherence were significantly more effective (OR 1.48, 95% CI 1.20-1.84, P<.001, I²=24.5%).

CONCLUSIONS

This systematic review and meta-analysis did not support the effectiveness of delivering smartphone-based interventions alone to achieve higher smoking abstinence rates. However, the efficacy of smartphone-based interventions increased when combined with pharmacotherapy-based smoking cessation approaches.

TRIAL REGISTRATION

PROSPERO CRD42021267615; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=267615.

Clinical Implication of Smoking-Related Aryl-Hydrocarbon Receptor Repressor (AHRR) Hypomethylation in Japanese Adults

BACKGROUND

Tobacco smoking is a leading preventable cause of morbidity and mortality worldwide; still, the success rate of smoking cessation is low in general. From the viewpoint of public health and clinical care, an objective biomarker of long-term smoking behavior is sought.Methods and Results:This study assessed DNA methylation as a biomarker of smoking in a hospital setting through a combination of molecular approaches including genetic, DNA methylation and mRNA expression analyses. First, in an epigenome-wide association study involving Japanese individuals with chronic cardiovascular disease (n=94), genome-wide significant smoking association was identified at 2 CpG sites on chromosome 5, with the strongest signal at cg05575921 located in intron 3 of the aryl-hydrocarbon receptor repressor (AHRR) gene. Highly significant (P<1×10^-27) smoking-cg05575921 association was validated in 2 additional panels (n=339 and n=300). For the relationship of cg05575921 methylation extent with time after smoking cessation and cumulative cigarette consumption among former smokers, smoking-related hypomethylation was found to remain for ≥20 years after smoking cessation and to be affected by multiple factors, such ascis-interaction of genetic variation. There was a significant inverse correlation (P=0.0005) between cg05575921 methylation extent andAHRRmRNA expression.

CONCLUSIONS

The present study results support that reversion of AHRR hypomethylation can be a quantifiable biomarker for progress in and observance of smoking cessation, although some methodological points need to be considered.