Table 1. Demographic characteristics and biochemical indices among bus drivers and stratified by metabolic syndrome (n = 707).
| Variables | All drivers (N = 707) | MetS (N = 327) | Non-MetS (N = 380) | p-value |
|---|---|---|---|---|
| Continuous variables | ||||
| Age (years), mean (SD) | 43.5 (6.9) | 43.8 (6.5) | 43.2 (7.2) | 0.285 |
| BMI (kg/m2), mean (SD) | 26.1 (4.0) | 28.4 (3.8) | 24.1 (3.0) | <0.001 |
| Systolic blood pressure (mmHg), mean (SD) | 126.9 (13.1) | 132.2 (12.2) | 122.4 (12.1) | <0.001 |
| Diastolic blood pressure (mmHg), mean (SD) | 80.9 (10.3) | 85.1 (10.0) | 77.3 (9.1) | <0.001 |
| Total cholesterol (mg/dl), mean (SD) | 203.5 (38.0) | 210.1 (38.0) | 197.8 (37.1) | <0.001 |
| Triglyceride (mg/dl), mean (SD) | 209.9 (181.3) | 287.1 (226.0) | 143.6 (87.9) | <0.001 |
| HDL cholesterol (mg/dl), mean (SD) | 37.7 (9.3) | 33.6 (7.0) | 41.2 (9.7) | <0.001 |
| Fasting blood glucose (mg/dl), mean (SD) | 102.7 (41.5) | 115.2 (53.2) | 91.9 (22.7) | <0.001 |
| Categorical variables | ||||
| CVD after follow-up | 0.012 | |||
| Yes | 77(10.9) | 46(14.1) | 31(8.2) | |
| No | 630(90.1) | 281(85.9) | 349(91.8) | |
| Marital status, n (%) | 0.899 | |||
| Unmarried | 123 (17.4) | 59 (18.0) | 64 (16.8) | |
| Married | 506 (71.2) | 233 (71.3) | 273 (71.8) | |
| Others | 78 (11.4) | 35 (10.7) | 43 (11.4) | |
| Education, n (%) | 0.563 | |||
| ≤ Junior high school | 206 (29.1) | 93 (28.4) | 113 (29.7) | |
| Senior high and vocational school | 451 (63.8) | 214 (65.4) | 237 (62.4) | |
| University and College | 50 (7.1) | 20 (6.2) | 30 (7.9) | |
| Cigarette smoking, n (%) | 0.033 | |||
| Never smokers | 241 (34.1) | 99 (30.3) | 142 (37.4) | |
| Ex-smokers | 47 (6.6) | 17 (5.2) | 30 (7.9) | |
| Current smokers | 414 (59.3) | 207 (64.5) | 207 (54.7) | |
| Missing n = 5 | ||||
| Alcohol use, n (%) | 0.489 | |||
| No | 557 (82.4) | 253 (77.4) | 304 (80.0) | |
| Yes | 146 (17.6) | 71 (22.6) | 75 (20.0) | |
| Missing n = 4 | ||||
| Betel nut chewing | 0.110 | |||
| No | 583 (82.5) | 262 (80.1) | 321 (84.5) | |
| Yes | 123 (17.5) | 65 (19.9) | 58 (15.5) | |
| Missing n = 1 | ||||
| Moderate exercise, n (%) | 0.159 | |||
| No | 516 (72.9) | 248 (75.8) | 268 (70.5) | |
| Yes | 181 (27.1) | 76 (24.2) | 105 (29.5) | |
| Missing n = 10 | ||||
| Working hour, n (%) | 0.134 | |||
| ≤ 12 hr | 424 (59.9) | 186 (56.9) | 238 (62.6) | |
| > 12 hr | 278 (40.1) | 138 (43.1) | 140 (37.4) | |
| Missing n = 5 | ||||
| SSOS, n (%) | 0.966 | |||
| + 2 ~ +1 | 161 (22.8) | 66 (20.2) | 95 (25.0) | |
| -2 ~ 0 | 544 (77.2) | 261 (79.8) | 283 (75.0) | |
| Missing n = 2 | ||||
| SOFI, n (%) | 0.610 | |||
| < 3.0 | 316 (44.7) | 143 (43.7) | 173 (45.5) | |
| ≥3.0 | 390 (55.3) | 184 (56.3) | 206 (54.2) | |
| Missing n = 1 | ||||
| Shift work, n (%) | 0.083 | |||
| No | 127 (17.9) | 50 (15.3) | 77 (20.3) | |
| Yes | 579 (82.1) | 277 (84.7) | 302 (79.5) | |
| Missing n = 1 | ||||
SD, standard deviation; MetS, metabolic syndrome; BMI, body mass index; HDL, high-density lipoprotein; SSOS, Stress Satisfaction Offset Score; SOFI, Swedish Occupational Fatigue Inventory