title: Comparison of Prevalence- and Smoking Impact Ratio-Based Methods of Estimating Smoking-Attributable Fractions of Deaths.
abstract: BACKGROUND
  Smoking is a major modifiable risk factor for premature mortality. Estimating the smoking-attributable burden is important for public health policy. Typically, prevalence- or smoking impact ratio (SIR)-based methods are used to derive estimates, but there is controversy over which method is more appropriate for country-specific estimates. We compared smoking-attributable fractions (SAFs) of deaths estimated by these two methods.
  
  
  METHODS
  To estimate SAFs in 2012, we used several different prevalence-based approaches using no lag and 10- and 20-year lags. For the SIR-based method, we obtained lung cancer mortality rates from the Korean Cancer Prevention Study (KCPS) and from the United States-based Cancer Prevention Study-II (CPS-II). The relative risks for the diseases associated with smoking were also obtained from these cohort studies.
  
  
  RESULTS
  For males, SAFs obtained using KCPS-derived SIRs were similar to those obtained using prevalence-based methods. For females, SAFs obtained using KCPS-derived SIRs were markedly greater than all prevalence-based SAFs. Differences in prevalence-based SAFs by time-lag period were minimal among males, but SAFs obtained using longer-lagged prevalence periods were significantly larger among females. SAFs obtained using CPS-II-based SIRs were lower than KCPS-based SAFs by >15 percentage points for most diseases, with the exceptions of lung cancer and chronic obstructive pulmonary disease.
  
  
  CONCLUSIONS
  SAFs obtained using prevalence- and SIR-based methods were similar for males. However, neither prevalence-based nor SIR-based methods resulted in precise SAFs among females. The characteristics of the study population should be carefully considered when choosing a method to estimate SAF.
authors.affiliation: Clinical Trial Center, Ewha Womans University Medical Center.
authors.forename: Kyoung Ae
authors.initials: KA
authors.lastname: Kong
authors.forename: Kyung-Hee
authors.initials: KH
authors.lastname: Jung-Choi
authors.forename: Dohee
authors.initials: D
authors.lastname: Lim
authors.forename: Hye Ah
authors.initials: HA
authors.lastname: Lee
authors.forename: Won Kyung
authors.initials: WK
authors.lastname: Lee
authors.forename: Sun Jung
authors.initials: SJ
authors.lastname: Baik
authors.forename: Su Hyun
authors.initials: SH
authors.lastname: Park
authors.forename: Hyesook
authors.initials: H
authors.lastname: Park
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002423:Cause of Death / Q000639:trends*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology* / Q000401:mortality