Table 1.
Demographic, smoking, and carbon monoxide (CO) exposure characteristics of participants based on self-reported smoking status.
| Heavy smokers | Light smokers | Exposed non-smokers | Not exposed non-smokers | Group differences | Smokers versus non-smokers | |
|---|---|---|---|---|---|---|
| (n = 46) | (n = 44) | (n = 36) | (n = 46) | |||
| Age (mean ± SD) | 38.0 ± 9.5 | 39.3 ± 10.5 | 36.4 ± 12.8 | 30.9 ± 11.5 | P = 0.002 | P = 0.002 |
| Years education (mean ± SD) | 12.4 ± 1.7 | 12.9 ± 2.0 | 12.8 ± 2.3 | 13.7 ± 2.0 | P = 0.010 | P = 0.028 |
| Gender (% female) | 34.8 | 29.5 | 38.9 | 43.5 | NS | NS |
| Race (%) | P = 0.035 | NS | ||||
| African American | 56.5 | 68.3 | 91.7 | 71.7 | ||
| Asian | 0 | 4.5 | 0 | 2.2 | ||
| Caucasian | 41.3 | 22.7 | 8.3 | 23.9 | ||
| Other | 2.2 | 4.5 | 0 | 2.2 | ||
| Ethnicity (% Hispanic) | 2.2 | 6.8 | 0 | 4.3 | NS | NS |
| Minutes since last cigarette (mean ± SD) | 109.3 ± 132.7 | 142.6 ± 216.1 | NA | NA | NS | NA |
| Number of cigarettes today (mean ± SD) | 4.6 ± 3.3 | 2.6 ± 1.6 | NA | NA | P = 0.001 | NA |
| Cigarettes per day (mean ± SD) | 18.4 ± 6.5 | 8.7 ± 1.7 | NA | NA | P < 0.001 | NA |
| Years smoking (mean ± SD) | 19.3 ± 10.0 | 20.1 ± 12.8 | NA | NA | NS | NA |
| Exposed to passive smoke at home (%) | 54.3 | 43.2 | 91.7 | 0 | P < 0.001 | NS |
| Frequency exposed at home (%) | P < 0.001 | P = 0.003 | ||||
| Daily | 45.7 | 34.1 | 41.7 | 0 | ||
| Weekly, less than daily | 8.7 | 9.1 | 38.9 | 0 | ||
| Monthly, less than weekly | 0 | 0 | 11.1 | 0 | ||
| Never or rarely | 45.6 | 56.8 | 8.3 | 100.0 | ||
| When exposed, hours per day (mean ± SD) | 5.2 ± 4.1 | 4.8 ± 3.3 | 2.2 ± 3.1 | NA | P = 0.004 | P = 0.001 |
| If exposed, hours since last exposure at home (mean ± SD) | 10.7 ± 13.4 | 18.5 ± 30.1 | 35.0 ± 39.5 | NA | P = 0.012 | P = 0.004 |
| Exposed to passive smoke at work (%) | 19.6 | 9.1 | 13.9 | 0 | P = 0.019 | NS |
| Frequency exposed at work (%) | NS | NS | ||||
| Daily | 15.2 | 9.1 | 8.3 | 0 | ||
| Weekly, less than daily | 4.3 | 0 | 5.6 | 0 | ||
| Monthly, less than weekly | 0 | 0 | 0 | 0 | ||
| Never or rarely | 80.4 | 90.9 | 86.1 | 100.0 | ||
| When exposed, hours per day (mean ± SD) | 3.4 ± 3.0 | 3.1 ± 3.5 | 1.4 ± 1.8 | NA | NS | NS |
| If exposed, hours since last exposure at work (mean ± SD) | 31.6 ± 28.2 | 24.1 ± 24.8 | 43.4 ± 46.0 | NA | NS | NS |
| Drive car daily (%) | 23.9 | 29.5 | 50.0 | 41.3 | NS | P = 0.03 |
| If yes, minutes in car per day (mean ± SD) | 245.9 ± 248.6 | 190.8 ± 143.0 | 145.8 ± 189.5 | 112.9 ± 102.2 | NS | NS |
| Ride public transit daily (%) | 63.0 | 61.4 | 47.2 | 40.0 | P = 0.033 | P = 0.006 |
| If yes, minutes waiting for and riding transit per day (mean ± SD) | 144.0 ± 90.8 | 152.4 ± 96.6 | 157.8 ± 82.4 | 178.5 ± 104.9 | NS | NS |
| Home in city (%) | 76.1 | 79.5 | 75.0 | 58.7 | NS | NS |
| Occupational exposure to CO (%) | 26.1 | 22.7 | 11.1 | 8.7 | NS | P = 0.011 |
| LCMSMS urine cotinine (ng/ml) | 1482.0 ± 737.4 | 1361.8 ± 767.6 | 5.7 ± 12.6 | 11.8 ± 53.2 | P < 0.001 | P < 0.001 |
| LCMSMS saliva cotinine (ng/ml) | 339.0 ± 190.4 | 269.8 ± 139.4 | 0.8 ± 2.1 | 0.4 ± 1.1 | P < 0.001 | P < 0.001 |
Occupational exposures include construction; cooking; bus, taxi, limousine driver; industrial plant; and car repair. Group differences based on F-values, except for comparisons of smoking behaviors between light and heavy smokers. These comparisons and comparisons between smokers and non-smokers are based on t-tests. Differences between categorical variables are based on Pearson χ2 tests. SD: standard deviation; LCMSMS: liquid chromatography-tandem mass spectrometry; NA: not applicable; NS: not significant.