International Health Policy Program -Thailand Journal Club: Tobacco and Lung Cancer Risk: A Systematic Review and Meta-Analysis Jiraboon Tosanguan

International Health Policy Program -Thailand Outline Introduction Comparative Risk Assessment (CRA) for smoking Systematic Review and Meta-Analysis on risk of lung cancer from tobacco. Conclusion 2

International Health Policy Program -Thailand 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 3

International Health Policy Program -Thailand 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. 4

International Health Policy Program -Thailand 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. 5

International Health Policy Program -Thailand Systematic Review 6 Papers identified through searches of Pubmed using keywords: “smoking AND "lung cancer” AND cohort AND risk” (n=729) Evaluated in Details (n=32) Excluded on basis of title and abstract if irrelevant, not about risk of LC from smoking etc. (n=695) 2 paper could not be obtained found Excluded if 1)No specific RR on Lung cancer (n=3) 2)RR on LC but not comparing smokers and non-smoker (n=5) 3)RR not sex-specific (n=1) 4)Irrelevant (n=2) Studies on risk of LC comparing smokers and non-smokers with sex-specific info (n=13) Paper included in SR (M=9, FM=8, Total=10) Excluded if data from the same cohort (n=2) Meta-analysis performed using Review Manager 5

Included Paper ReferenceStudy PeriodNo. of subjects for analysis Source of subjectsEvent followed CategoryRRConfounding variables considered Kenfield et al womenfemale US registered nurses aged residing in 11 states MortalityFemale: Never Current Former ( ) 6.31 ( ) [HR] age, history of hypertension, DM, high cholesterol, BMI, weight change, alcohol intake, physical activities, previous use of oral contraceptives, HRT, menopausal status, family history of MI Freedman et al men, women Members of American Association of Retired Persons, aged residing in 8 states IncidenceMale Current Female Current (According to dose) Age, BMI, education, physical activities, alcohol intake, diet, pipe&cigar use, total energy intake. Bae J-M et al menMale beneficiaries of the Korean Medical Insurance Corporation (KMIC) incidenceMale Current4.18 ( )age, intake of coffee, raw fish and retinol. Jee S H et al Koreans eligible for the KMIC Mortality and incidence Male Current (incidence) Male Current (Mortality) Female Current (Incidence) Female Current (Mortality) 4.0 ( ) 4.6 ( ) 2.2 ( ) 2.5 ( ) age Thun et al 1997 (CPS-2) friends, neighbours and acquaintances of ACS volunteers from 50 states, born between mortalityMale Current Female Current 23.2 ( ) 12.8 ( ) age 7

Included Paper ReferenceStudy Period No. of subjects for analysis Source of subjects Event followed CategoryRR Confounding variables considered Wakai K et al (Pooled analysis) (4 studies) menvarious cohorts from different parts of Japan mortalityMale Current4.71 ( )age, and cohort Huxley R et al 2007 (Pooled Analysis) 31 studies ( ) (83% Asian 34% female) 31 studies in Australia, NZ, China, Japan, Singapore, S Korea, Taiwan and other Asian countries. MortalityMale Current (Asian) Male Current (ANZ) Female Current (Asian) Female Current (ANZ) 2.48 ( ) 9.87 ( ) 2.35 ( ) ( ) Wakai K et al (Meta-analysis) 22 studies ( ) 8 cohorts (3 pop-based) 14 case-control (all hosp-based) Mortality and incidence Male Current Female Current 4.39 ( ) 2.79 ( ) Jacobs D R et al 1999 (Pooled Analysis) 25 studies men16 cohorts in 9 countries (US, Finland, Holland, Italy, Croatia, Serbia, Greece, Japan) MortalityMale: Current 1-9 > ( ) 6.5 ( ) age, residence, BMI, Cholesterol, BP, history of CHD. Liu et al 1998 (Retrospective proportional mortality study) interviewed family members of 1 million who died between areas of China (24 cities and 74 rural counties) N/AMale Current >70 Female Current > (0.05) 2.47 (0.07) 2.64 (0.08) 2.50 (0.09) age, resident 8

International Health Policy Program -Thailand Meta-Analysis Results: Female 9

International Health Policy Program -Thailand Meta-Analysis Results: Males 10

International Health Policy Program -Thailand 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. 11