Odds ratios (ORs) were estimated by unconditional logistic
regression models adjusted for age, ethnicity, socioeconomic
status (SES) measured by the median
family income for census tract of residence and by education
level, and smoking history as synthesized by the
comprehensive smoking index (CSI). The CSI integrates
into a single index information on smoking duration,
smoking intensity, and time since cessation and it has
been shown to be useful for the purpose of adjusting for
smoking in lung cancer studies . We first performed