Dataset Information

Association of smoking reduction and mortality: protocol for a systematic review and meta-analysis of longitudinal observational studies.

ABSTRACT:

Introduction

Strong evidence shows that smoking cessation decreases mortality. Much less is known regarding the association between reduction in cigarettes per day (CPD) and mortality. The primary aim of this systematic review is to compare the mortality risk between smokers achieving a sustained reduction of CPD and smokers maintaining their smoking rate. The secondary aims are to compare the mortality risk between smokers achieving complete, sustained smoking cessation and (1) smokers maintaining their smoking rate and (2) smokers who achieved a sustained reduction in smoking rate.

Methods and analysis

MEDLINE, Web of Sciences and Embase will be searched using a prespecified search strategy, up to 23 November 2020, and will be limited to studies published in English and in French. Longitudinal observational studies using individual data including smokers with at least two distant CPD assessments and a follow-up period of systematic mortality data recording will be included. The main outcome will be the all-cause mortality. The secondary outcome will be specific mortality. The Newcastle-Ottawa Scale will be used to assess the risk of bias of individual studies. Outcomes will be analysed using HRs. All other outcomes' effect size reported in included studies will be converted in HRs using validated methods.

Ethics and dissemination

We intend to publish the results of our review in a peer-reviewed journal and to present the findings at national and international meetings and conferences.

Prospero registration number

CRD42019138354.

SUBMITTER: Aubin HJ

PROVIDER: S-EPMC7818821 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature

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Publications

Association of smoking reduction and mortality: protocol for a systematic review and meta-analysis of longitudinal observational studies.

Aubin Henri-Jean HJ Ali Oicheih Laetitia L Gabriel Sonia S Berlin Ivan I

BMJ open 20210120 1

<h4>Introduction</h4>Strong evidence shows that smoking cessation decreases mortality. Much less is known regarding the association between reduction in cigarettes per day (CPD) and mortality. The primary aim of this systematic review is to compare the mortality risk between smokers achieving a sustained reduction of CPD and smokers maintaining their smoking rate. The secondary aims are to compare the mortality risk between smokers achieving complete, sustained smoking cessation and (1) smokers ...[more]

PMID: 33472771

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Project description:Objectives We conducted a systematic literature review and meta-analysis of observational studies to investigate the association between diabetes, hypertension, body mass index (BMI) or smoking with the risk of death in patients with COVID-19 and to estimate the proportion of deaths attributable to these conditions. Methods Relevant observational studies were identified by searches in the PubMed, Cochrane library and Embase databases through 14 November 2020. Random-effects models were used to estimate summary relative risks (SRRs) and 95% CIs. Certainty of evidence was assessed using the Cochrane methods and the Grading of Recommendations, Assessment, Development and Evaluations framework. Results A total of 186 studies representing 210 447 deaths among 1 304 587 patients with COVID-19 were included in this analysis. The SRR for death in patients with COVID-19 was 1.54 (95% CI 1.44 to 1.64, I2=92%, n=145, low certainty) for diabetes and 1.42 (95% CI 1.30 to 1.54, I2=90%, n=127, low certainty) for hypertension compared with patients without each of these comorbidities. Regarding obesity, the SSR was 1.45 (95% CI 1.31 to 1.61, I2=91%, n=54, high certainty) for patients with BMI ≥30 kg/m2 compared with those with BMI <30 kg/m2 and 1.12 (95% CI 1.07 to 1.17, I2=68%, n=25) per 5 kg/m2 increase in BMI. There was evidence of a J-shaped non-linear dose–response relationship between BMI and mortality from COVID-19, with the nadir of the curve at a BMI of around 22–24, and a 1.5–2-fold increase in COVID-19 mortality with extreme obesity (BMI of 40–45). The SRR was 1.28 (95% CI 1.17 to 1.40, I2=74%, n=28, low certainty) for ever, 1.29 (95% CI 1.03 to 1.62, I2=84%, n=19) for current and 1.25 (95% CI 1.11 to 1.42, I2=75%, n=14) for former smokers compared with never smokers. The absolute risk of COVID-19 death was increased by 14%, 11%, 12% and 7% for diabetes, hypertension, obesity and smoking, respectively. The proportion of deaths attributable to diabetes, hypertension, obesity and smoking was 8%, 7%, 11% and 2%, respectively. Conclusion Our findings suggest that diabetes, hypertension, obesity and smoking were associated with higher COVID-19 mortality, contributing to nearly 30% of COVID-19 deaths. Trial registration number CRD42020218115.

Project description:BackgroundDisturbed cognitive function is associated with several causes of mortality; however, the association between cognitive function and the risk of cancer death has not been extensively investigated yet. We aimed to evaluate the association of cognitive function with the risk of cancer death and all-cause mortality in the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER) and Leiden 85-plus Study. Additionally, a systematic review and meta-analysis of longitudinal studies were conducted to evaluate the association of cognitive function and risk of cancer death.MethodsRisk of cancer death and all-cause mortality were reported using hazard ratios (HRs) with 95% confidence interval (CI) in tertiles of cognitive function of PROSPER and Leiden85-Plus Study. Additionally, PubMed, Embase, Web of Science, Cochrane, PsycINFO, Academic Search Premier, CINHAL, and Emcare were searched up to November 1st, 2020 to perform a systematic review and meta-analysis. The relative risks (RRs) with 95%CI of cancer death per each standard deviation lower performance in cognitive measurements were calculated.ResultsParticipants of PROSPER had 1.65-fold (95%CI 1.11-2.47) greater risk of cancer death (P for trend = 0.016) and 1.85-fold (95%CI 1.46-2.34) higher risk of all-cause mortality (P for trend<0.001), in multivariable models. Results of the Leiden-85 Plus Study showed that subjects with MMSE score below 24 had a lower chance of cancer death (HR 0.79, 95%CI 0.36-1.70, P for trend = 0.820) but had 2.18-fold (95%CI 1.57-3.02) higher risk of all-cause mortality compared to the reference group (P for trend<0.001). Besides, the results of systematic review and meta-analysis showed that per each standard deviation lower performance in cognitive function, individuals were at a 10% higher chance of cancer death (RR 1.10, 95%CI 1.00-1.20, P-value = 0.044).ConclusionsLower cognitive function performance is associated with a marginally increased risk of cancer death, in line with a significantly greater risk of all-cause mortality.

Dataset Information

Association of smoking reduction and mortality: protocol for a systematic review and meta-analysis of longitudinal observational studies.

Introduction

Methods and analysis

Ethics and dissemination

Prospero registration number

Publications

Association of smoking reduction and mortality: protocol for a systematic review and meta-analysis of longitudinal observational studies.

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