From: Methodologies used to estimate tobacco-attributable mortality: a review
 | Peto's et al method | Prevalence-based analysis in case-control studies | Basic method |
---|---|---|---|
Variation respect prevalence-based analysis in cohort studies | Problem: Smoking prevalence is a poor proxy for cumulative hazards of smoking. Solution: Defining SIR (Smoking impact ratio or Synthetic prevalence) authors avoid prevalence limitations. | Problem: RR extrapolation to different populations than the original is inconsistent. Solution: Designing a case-control study OR could be assessed. | Problem: RR extrapolation to different populations than the original is inconsistent. Solution: RR can be estimated applying a calculation procedure. |
Calculation procedure |
where CLC, NLC, S*LC, N*LC are age-sex specific lung cancer mortality rates for smokers and never smokers in the study and in the reference population (*). |
where p1 is the prevalence between the cases a1 is exposed cases b1 is exposed controls a0 is non exposed cases b0 is non exposed controls | Packs-function in smokers RRs = 1 + ac((t - 5))-t0) Multistage-function in smokers RRs = 1 + [(t - 5)4.5 + ac(1 + 2ac)((t - 5)-t0)4.5 + 2ac((t - 5)4.5-t0 4.5)]/(t - 5)4.5 Where a is a constant, c is the number of packs of cigarettes smoked per year, t is the current age and t 0 is age at start of smoking. In former smokers t1 replaces (t - 5) and t1 is age at stop smoking. |