Table 1.
Characteristics of the Study Participants
| Office Workers (n = 60) |
Truck Drivers (n = 60) |
p-valuea | ||
|---|---|---|---|---|
| Sex, n (%) | ||||
| Male | 40 (66.67) | 40 (66.67) | ||
| Female | 20 (33.33) | 20 (33.33) | 1.00 | |
| Age [Years], mean ± SD | 30.27 ± 7.96 | 33.53 ± 5.65 | 0.004 | |
| Smoking, n (%) | ||||
| Never smoker | 35 (58.33) | 34 (56.67) | ||
| Ex-smoker | 2 (3.33) | 2 (3.33) | ||
| Actual smoker | 23 (38.33) | 24 (40) | 1.00 | |
| Pack-years of smoking [kg/m2], mean ± SDb | 2.87 ± 3.59 | 11.7 ± 11.2 | <0.001 | |
| Cigarettes smoked during the study timec [cigarettes/day], mean ± SD | 2.85 ± 5.21 | 6.39 ± 9.41 | <0.001c | |
| BMI [kg/m2], mean ± SD | 22.76 ± 3.38 | 24.27 ± 3.21 | 0.01 | |
| Tea consumption during the time of the studyc, n (%) | ||||
| No | 109 (90.83) | 86 (71.67) | ||
| Yes | 11 (9.17) | 34 (28.33) | 0.003c | |
| Day of the weekc, n (%) | ||||
| Monday | 16 (13.33) | 19 (15.83) | ||
| Tuesday | 18 (15) | 13 (10.83) | ||
| Wednesday | 14 (11.67) | 15 (12.5) | ||
| Thursday | 15 (12.5) | 20 (16.67) | ||
| Friday | 17 (14.17) | 19 (15.83) | ||
| Saturday | 18 (15) | 16 (13.33) | ||
| Sunday | 22 (18.33) | 18 (15) | 0.88c | |
| Usual alcohol drinking, n (%) | ||||
| Yes | 14 (23.33) | 31 (51.67) | ||
| No | 46 (76.67) | 29 (48.33) | 0.002 | |
aP-values were calculated using Student's t-test and Fisher's exact test for continuous and categorical variables, respectively, except for the variables indicated at the footnote c below.
bOnly current or former smokers.
cCumulative of the two study days. Based on 240 total observations (120 study days for office workers and 120 study days for truck drivers). P-values were obtained from mixed-effect regression models.