Most of the participants were white; the majority were married and had a higher level of education than the general population24,25 (Table 1). In the contemporary cohorts, approximately half the participants had at least a college or nursing-school education. At least 20% of participants in all the cohorts had no education beyond high school, a proportion that allowed us to perform analyses stratified according to or adjusted for educational level. In the contemporary cohorts, the prevalence of current smoking decreased over time to 9.3% among men and 9.7% among women, findings that are consistent with trends in the educated general population.26 More than half the current smokers in the contemporary cohorts reported smoking fewer than 20 cigarettes per day in 2000; about 25% had smoked for 50 or more years. Additional baseline characteristics are provided in Table S1 in the Supplementary Appendix.
