Baseline characteristics of participants stratified by traffic proximity*
| Characteristic | All participants (n=509) | Close to major roads (n=117) | Away from major roads (n=392) | p Value† |
|---|---|---|---|---|
| Age (year) | 46.8±9.0 | 47.2±9.2 | 46.7±8.9 | 0.581 |
| Sex, male (%) | 49 | 51 | 49 | 0.593 |
| Race (%) | 0.008 | |||
| Aboriginal | 14 | 22 | 12 | |
| Chinese | 30 | 32 | 29 | |
| European | 29 | 27 | 30 | |
| South Asian | 27 | 19 | 29 | |
| Education (%) | 0.589 | |||
| ≤High school | 27 | 29 | 27 | |
| >High school | 73 | 71 | 73 | |
| Annual household income (%) | 0.019 | |||
| <$30 000 | 24 | 29 | 22 | |
| $30 000 to $60 000 | 37 | 43 | 35 | |
| ≥$60 000 | 39 | 28 | 43 | |
| Smoke status (%) | 0.357 | |||
| Current | 7 | 9 | 6 | |
| Former | 27 | 24 | 28 | |
| Never | 66 | 67 | 66 | |
| Alcohol intake (yes, %) | 32 | 30 | 32 | 0.649 |
| Physical activity (hours per week)‡ | 3.5 (1.7–6.5) | 2.9 (1.6–6.5) | 1.3 (0.9–1.8) | 0.258 |
| Body mass index (kg/m2) | 27.2±4.7 | 27.5±4.3 | 27.1±4.8 | 0.459 |
| SBP (mm Hg) | 118±15 | 117±14 | 118±15 | 0.357 |
| DBP (mm Hg) | 77±9 | 77±10 | 77±9 | 0.826 |
| Total cholesterol (mmol/L) | 5.2±1.0 | 5.2±1.1 | 5.3±1.0 | 0.667 |
| LDL-C (mmol/L) | 3.2±0.9 | 3.2±0.9 | 3.3±0.9 | 0.311 |
| HDL-C (mmol/L) | 1.3±0.4 | 1.3±0.4 | 1.3±0.4 | 0.637 |
*Data are presented as percentage for categorical variables or mean±SD for continuous variables; unless otherwise specified.
†For comparisons between the group close to and the group away from major roads.
‡Median (IQR).
DBP, diastolic blood pressure; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; SBP, systolic blood pressure.