Table 1.
Demographics, Smoking-Related Characteristics and Hormone Levels by Study Group
| Oral Contraceptives Users (OC) (n=14) | Naturally Cycling Participants (NC) (n=28) | p-value | |
|---|---|---|---|
| Age, Mean ± SE | 24.2 ± 1.1 | 26.2 ± 1.1 | <.001 |
| Education, n (%) at least some college | 13 (92.9%) | 26 (92.9%) | 1.00 |
| White, n (%) Non-Hispanic race | 12 (85.7%) | 21 (75.0%) | .437 |
| Cigarettes per day, Mean ± SE | 10.5 ± 1.3 | 11.6 ± 1.0 | .468 |
| Nicotine dependence (FTND score), Mean ± SE | 2.6 ± 0.5 | 3.4 ± 0.5 | .011 |
| Time to first cigarette in the morning, n (%) | |||
| 5 minutes or less | 2 (14.3%) | 2 (7.1%) | .024 |
| 6-30 minutes | 4 (28.6%) | 14 (50.0%) | |
| 31-60 minutes | 1 (7.1%) | 10 (35.7%) | |
| More than 60 minutes | 7 (50.0%) | 2 (7.1%) | |
| Study week order | |||
| Anticipated low progesterone week first | 8 (57.1%) | 13 (46.4%) | .513 |
| Anticipated high progesterone week first | 6 (42.9%) | 15 (53.6%) | |
| Hormones, Mean ± SE | |||
| Anticipated Low Progesterone Week | |||
| Ad Libitum Smoking | |||
| Progesterone (ng/ml) | 0.51 ± 0.12 | 0.94 ± 0.09 a | 0.009 |
| Estradiol (pg/ml) | 21.41 ± 7.82 | 54.28 ± 5.42 a | 0.002 |
| Progesterone/Estradiol ratio | 25.68 ± 6.87 | 26.47 ± 4.76 a | 0.926 |
| Smoking Abstinence | |||
| Progesterone (ng/ml) | 0.56 ± 0.08 | 0.72 ± 0.06 a | 0.154 |
| Estradiol (pg/ml) | 26.00 ± 11.87 | 68.21 ± 8.58 a | 0.006 |
| Progesterone/Estradiol ratio | 30.43 ± 4.63 | 16.86 ± 3.45 a | 0.017 |
| Anticipated High Progesterone Week | |||
| Ad Libitum Smoking | |||
| Progesterone (ng/ml) | 0.45 ± 1.34 | 7.91 ± 0.87 b | <.001 |
| Estradiol (pg/ml) | 21.36 ± 14.85 | 122.38 ± 9.66 b | <.001 |
| Progesterone/Estradiol ratio | 32.86 ± 13.12 | 71.92 ± 8.54 b | 0.021 |
| Smoking Abstinence | |||
| Progesterone (ng/ml) | 0.45 ± 1.24 | 11.44 ± 0.88 b | <.001 |
| Estradiol (pg/ml) | 13.81 ± 18.61 | 148.01 ± 14.15 b | <.001 |
| Progesterone/Estradiol ratio | 44.06 ± 14.60 | 86.69 ± 10.33 b | 0.025 |
Notes. p-values are from linear/generalized linear mixed models with a random intercept for matched set, FTND = Fagerstrom test for nicotine dependence
a
Value significantly (p<0.001) different from corresponding hormone values during the Anticipated High Progesterone Week.
b
Value significantly (p<0.001) different from corresponding hormone values during the Anticipated Low Progesterone Week.