Table 1.

Demographic characteristics and smoking behavior history for participants (n = 202) at screening.

Characteristic	Total enrolled (n = 202)	Follicular quit group (n = 106)	Luteal quit group (n = 96)	P-value
Demographics†
Age (years)	29.8 ± 6.6	29.0 ± 6.4	30.6 ± 6.7	0.101
Education (years)	13.7 ± 2.0	13.7 ± 2.2	13.7 ± 1.7	0.974
Ethnic origin‡§
African American	4%	6%	2%	0.460
American Indian	9%	11%	7%
Asian	3%	2%	4%
White	82%	79%	84%
Other	3%	3%	2%
Hispanic¶	2%	2%	1%	0.614
Marital status§
Single	54%	58%	50%	0.333
Divorced	14%	12%	16%
Separated	2%	1%	3%
Married	30%	29%	31%
Yearly family income§
≤ $30 000	49%	52%	45%	0.779
$30 001–60 000	34%	29%	38%
> $60 000	18%	19%	17%
Smoking history†
Years of smoking	13.1 ± 7.0	12.6 ± 7.6	13.6 ± 7.0	0.316
Number cigarettes/day	16.6 ± 5.6	15.8 ± 4.7	17.5 ± 6.5	0.033
Fagerstrom score (1–11)††	4.1 ± 2.0	4.4 ± 1.9	3.8 ± 2.1	0.031
Number of quit attempts	2.7 ± 2.1	2.7 ± 1.9	2.8 ± 2.3	0.786*
Longest days abstinent	208.0 ± 489.7	141.5 ± 242.9	279.6 ± 653.5	0.578*
Screening measures†
PAF total	25.1 ± 9.5	25.1 ± 9.5	25.1 ± 9.6	0.993
PAF affect	10.0 ± 4.2	10.1 ± 4.1	9.9 ± 4.3	0.777
PAF pain	7.8 ± 3.6	8.0 ± 3.8	7.6 ± 3.5	0.418
PAF water	7.3 ± 3.4	7.0 ± 3.4	7.6 ± 3.5	0.240
MNWS total	5.3 ± 4.8	5.3 ± 4.7	5.2 ± 4.9	0.857
MNWS craving	2.7 ± 0.9	2.8 ± 0.7	2.6 ± 1.0	0.068
QSU factor 1	4.9 ± 1.2	4.9 ± 1.2	4.9 ± 1.2	0.965
QSU factor 2	2.8 ± 1.1	2.8 ± 1.1	2.8 ± 1.1	0.864
CO	17.7 ± 8.7	17.2 ± 8.0	18.3 ± 9.4	0.350
Cotinine	224.6 ± 112.4	210.1 ± 95.2	241.1 ± 128.8	0.235

^*t-test performed on the log of these numbers.

^†Statistics reported as means ± standard deviation unless otherwise noted.

^‡Reported as frequency (%).

^§P-value for categorical items is the Spearman’s correlation.

^¶Reported separately from race.

^††Fagerstrom (1978). PAF: Premenstrual Assessment Form; MNWS: Minnesota Nicotine Withdrawal Scale; QSU: Questionnaire on Smoking Urges; CO: carbon dioxide.