data for smoking status, and few observations with missing data for incense burning (four cases) and SHS (one case) exposure. Data from 1,109 lung cancer cases and 1,015 referents with complete information were included in the analyses. Generally, there were no significant differences in major characteristics (e.g., education, place of birth, alcohol drinking and smoking habits, family cancer history, and meat intakes) between cases or referents with missing data and those included in the analysis, with the exception of age. The referents with missing data were 4.4 years younger, on average, than