Table 1.
Summary statistics of population demographic characteristics [median (range) or n (%)].
| Controls (n = 140)a | < 1 ppm (n = 70) | 1 to < 10 ppm (n = 149) | ≥ 10 ppm (n = 31) | p-Valueb | |
|---|---|---|---|---|---|
| Age (years) | 28 (18–51) | 28 (19–46) | 27 (18–49) | 36 (21–52) | 0.02 |
| BMI (kg/m2) | 21.6 (16.0–38.5) | 22.3 (15.4–30.1) | 22.0 (15.4–32.3) | 21.3 (17.7–28.3) | 0.89 |
| Sex [n (%)] | 0.30 | ||||
| Male | 52 (37) | 30 (43) | 45 (30) | 11 (35) | |
| Female | 88 (63) | 40 (57) | 104 (70) | 20 (65) | |
| Current alcohol use [n (%)] | 0.41 | ||||
| Yes | 43 (31) | 20 (29) | 35 (23) | 11 (35) | |
| No | 97 (69) | 50 (71) | 114 (77) | 20 (65) | |
| Current smoker [n (%)] | 0.19 | ||||
| Yes | 39 (28) | 17 (24) | 26 (17) | 8 (26) | |
| No | 101 (72) | 53 (76) | 123 (83) | 23 (74) | |
| Urinary benzene (μg/L) | 0.120 (0.007–10.1) | 7.89 (0.667–72.5) | 23.8 (0.50–1,400) | 359 (5.20–4,210) | < 0.001 |
| Airborne benzene (ppm) | 0.004 (< 0.01–0.53)c | 0.46 (0.26–1.00) | 2.07 (1.02–9.87) | 19.1 (10.0–54.5) | < 0.001 |
a
One missing datum for urinary (airborne) benzene (n = 139), and two missing data for BMI (n = 138).
b
Wilcoxon rank-sum test or chi-square test between smokers and nonsmokers.
c
Estimated from urinary benzene concentrations.