Table 2.

Demographics

	Combination of Study 1 + Study 2 (N=1071)	Study 1 (N=608)	Study 2 (N=463)	Study 3 (N = 481)
% Women*	54.6	57.9	50.3	54.7
% White*	82.4	76.0	90.8	65.2
% African-American*	14.8	22.0	5.5	28.3
% high school or greater education*	92.9	90.7	95.7	95.9
% Married	45.0	46.5	43.0	44.7
Age (SD)*	40.48 (11.79)	41.78 (11.34)	38.76 (12.16)	45.49 (10.35)
Mean cigarettes per day (SD)	22.22 (10.11)	22.44 (9.87)	21.93 (10.44)	21.76 (9.84)
Baseline CO in ppm (SD)*	25.98 (11.80)	27.11 (11.69)	24.51 (11.80)	24.40 (12.59)

^*Statistically significant differences between the Study 1 and Study 2. Study 3 was not compared as it was not combined with any other data set.