Table 1.
Characteristics of the study population.
| Category | Low OPA (n = 338) | Moderate/ high OPA (n = 654) | P-value |
|---|---|---|---|
| Age (years, mean ± SD) | 40.1 ± 13.5 | 47.3 ± 10.2 | < 0.01a |
| Gender (man/woman, n, %) | 279/59 (82.5/17.5) | 563/91 (86.1/13.9) | 0.14c |
| Seniority (years, mean ± SD) | 11.3 ± 8.5 | 14.3 ± 9.1 | < 0.01a |
| Body mass index (kg/m2, n, %) | 23.7 ± 3.3 | 23.7 ± 3.4 | 0.71a |
| Education (< 9/≥9 years, n, %) | 116/222 (34.3/65.7) | 530/124 (81.0/19.0) | < 0.01c |
| Married (yes/no, n, %) | 202/136 (59.8/40.2) | 516/138 (78.9/21.9) | < 0.01c |
| Smoking (yes/no, n, %) | 134/204 (39.6/60.4) | 269/385 (41.1/58.9) | 0.03c |
| Drinking alcohol (yes/no, n, %) | 98/240 (29.0/71.0) | 246/390 (40.4/59.6) | < 0.01c |
| Bland diet habit (yes/no, n, %) | 79/259 (23.4/76.6) | 133/521 (20.3/79.7) | 0.03c |
| Average monthly earnings (¥ [yuan], n, %) | < 0.01c | ||
| < 5,000 | 142 (42.0) | 300 (45.9) | |
| 5,000–7,500 | 107 (31.7) | 279 (42.7) | |
| >7,500 | 89 (26.3) | 75 (11.5) | |
| Systolic blood pressure (mmHg, mean ± SD) | 123.88 ± 17.69 | 129.93 ± 17.85 | < 0.01a |
| Diastolic blood pressure (mmHg, mean ± SD) | 74.49 ± 11.89 | 77.28 ± 11.52 | < 0.01a |
| Heart rate (time/min, mean ± SD) | 80.37 ± 10.91 | 78.39 ± 11.30 | < 0.01a |
| Alanine aminotransferase (IU/L, median, IQR) | 19.50 (13.38, 29.15) | 17.70 (13.30, 25.10) | < 0.05b |
| AST (IU/L, median, IQR) | 19.40 (16.30, 23.50) | 20.20 (16.60, 24.50) | 0.07b |
| Albumin (g/L, mean ± SD) | 46.40 ± 2.73 | 45.55 ± 2.55 | < 0.01a |
| Fasting plasma glucose (moll/L, median, IQR) | 4.82 (4.51, 5.34) | 4.88 (4.53, 5.37) | 0.48b |
| Total cholesterol (mmol/L, median, IQR) | 4.67 (4.17, 5.29) | 4.74 (4.32, 5.38) | < 0.05b |
| Triglyceride (mmol/L, median, IQR) | 2.31 (1.52, 2.31) | 2.31 (1.46, 2.31) | 0.09b |
| White blood cell count (109/L, median, IQR) | 6.06 (5.25, 7.23) | 5.73 (4.88, 6.71) | < 0.01b |
| Platelet count (109/L, median, IQR) | 222.52 (193.75, 255.00) | 221.00 (190.75, 247.25) | 0.17b |
| Lymphocyte count (109/L, median, IQR) | 1.96 (1.65, 2.31) | 1.96 (1.62, 2.26) | 0.44b |
| Red blood cell count (1012/L, median, IQR) | 4.97 (4.62, 5.23) | 4.89 (4.60, 5.14) | < 0.01b |
| Mean platelet volume (fl, median, IQR) | 10.30 (9.60, 11.00) | 10.10 (9.50, 10.90) | 0.14b |
| Platelet distribution width (%, median, IQR) | 16.20 (15.90, 16.40) | 16.10 (15.90, 16.40) | 0.51b |
| Red blood cell distribution width (%, median, IQR) | 12.80 (12.40, 13.20) | 12.80 (12.50, 13.20) | 0.13b |
| NFS (mean ± SD) | −2.74 ± 1.24 | −2.26 ± 1.14 | < 0.01a |
| FIB-4 (median, IQR) | 0.77 (0.50, 1.10) | 1.02 (0.77, 1.36) | < 0.01b |
| APRI (median, IQR) | 0.22 (0.17, 0.29) | 0.23 (0.19, 0.30) | < 0.05b |
| AAR (median, IQR) | 0.97 (0.78, 1.29) | 1.12 (0.91, 1.35) | < 0.01b |
| RPR (median, IQR) | 0.06 (0.05, 0.06) | 0.06 (0.05, 0.07) | 0.11b |
OPA, occupational physical activity; IQR, interquartile range; AST, aspartate aminotransferase; NFS, non-alcoholic fatty liver disease fibrosis score; FIB-4, fibrosis index based on the four factors; APRI, aspartate aminotransferase to platelet ratio index; AAR, aspartate aminotransferase to alanine aminotransferase ratio; RPR, red blood cell distribution width to platelet.
aStudent's t-test was used for comparing the means of the continuous variables between the two groups.
bThe Mann–Whitney test was used to compare differences in non-normal variable distributions between the two groups.
cChi-square test was used to compare categorical variables between the two groups.