Methodological issues in estimating smoking-attributable mortality in the United States

The authors explored two methodological issues in the estimation of smoking -attributable mortality for the United States. First, age-specific and age- adjusted relative risk, attributable fraction, and smoking-attributable mor tality estimates obtained using data from the American Cancer Society's sec ond Cancer Prevention Study (CPS II), a cohort study of 1.2 million partici pants (1982-1988), were compared with those obtained using a combination of data from the National Mortality Follow-back Survey (NMFS), a representati ve sample of US decedents in which information was collected from informant s (1986), and the National Health Interview Survey (NHIS), a nationally rep resentative household survey (1987). Second, the potential for residual con founding of the disease-specific age-adjusted smoking-attributable mortalit y estimates was addressed with a model-based approach. The estimated smokin g-attributable mortality based on the CPS II for the four most common smoki ng-related diseases-lung cancer, chronic obstructive pulmonary disease, cor onary heart disease, and cerebrovascular disease-was 19% larger than the es timated smoking-attributable mortality based on the NMFS/NHIS, yet the two data sources yielded essentially the same smoiting-attributable mortality e stimate for lung cancer alone. Further adjustment of smoking-attributable m ortality for disease-appropriate confounding factors (education, alcohol in take, hypertension status, and diabetes status) indicated little residual c onfounding once age was taken into account.