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Journal Club: Tobacco and Lung Cancer Risk: A Systematic Review and Meta-Analysis. Jiraboon Tosanguan. Outline. Introduction Comparative Risk Assessment (CRA) for smoking Systematic Review and Meta-Analysis on risk of lung cancer from tobacco. Conclusion. Introduction.
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Journal Club: Tobacco and Lung Cancer Risk: A Systematic Review and Meta-Analysis Jiraboon Tosanguan
Outline • Introduction • Comparative Risk Assessment (CRA) for smoking • Systematic Review and Meta-Analysis on risk of lung cancer from tobacco. • Conclusion
Introduction • Smoking has been causally associated with increased risk of premature mortality from lung cancer as well as other medical cause. • Smoking in Thailand: • 9.49 million regular smokers (2007) • Male:Female ~ 23:1 (2007) • The majority is in the lower socioeconomic status group • Disease burden attributed by smoking can be an important input for policymakers to formulate strategies for improving population health and priority setting
Comparative Risk Assessment • “Systematic evaluation of the changes in population health which would result from modifying the population exposure to a risk factor.” • The Population Attributable Fraction (PAF) approach is used.
CRA Methods for Smoking • Smoking Impact Ratio (SIR) Approach (Peto et al 1992) • Lung cancer mortality is an indicator of the accumulative hazard of smoking and the ‘maturity’ of smoking epidemic in a population • SIR can be used as ‘summarized’ prevalence.
Systematic Review Papers identified through searches of Pubmed using keywords: “smoking AND "lung cancer” AND cohort AND risk” (n=729) 2 paper could not be obtained found Excluded on basis of title and abstract if irrelevant, not about risk of LC from smoking etc. (n=695) Evaluated in Details (n=32) • Excluded if • No specific RR on Lung cancer (n=3) • RR on LC but not comparing smokers and non-smoker (n=5) • RR not sex-specific (n=1) • Irrelevant (n=2) Studies on risk of LC comparing smokers and non-smokers with sex-specific info (n=13) Excluded if data from the same cohort (n=2) Paper included in SR (M=9, FM=8, Total=10) Meta-analysis performed using Review Manager 5
Meta-Analysis • Results: Female
Meta-Analysis • Results: Males
Conclusion • From the review, It has been observed about the differences between relative risk in US and Asian populations. • The relative risks for lung cancer comparing current smokers and never-smokers were estimated to be 6.16 and 8.09 in male and female respectively. • However, heterogeneity is high. Scope of meta-analysis may need to be reconsidered or alternative methods may be required.