Table 1.
Subject characteristics according to the presence of NAFLD
| Variables | Non-NAFLD group | NAFLD group | P-value |
|---|---|---|---|
| Unweighted number, n (%) | 8,168 (69.6) | 3,570 (30.4) | |
| Estimated population, n (%) | 16,415,120 (69.8) | 7,131,971 (30.2) | |
| Age (years), % | 45.93 (45.22–46.64) | 51.81 (50.84–52.78) | <0.001 |
| 20–39 | 36.9 (34.8–39.1) | 23.9 (21.4–26.6) | <0.001 |
| 40–59 | 42.1 (40.2–44.0) | 40.7 (38.3–43.1) | <0.001 |
| 60+ | 21.0 (19.6–22.5) | 35.4 (33.1–37.8) | <0.001 |
| Sex (male), % | 35.8 (34.2–37.4) | 48.3 (45.8–50.8) | <0.001 |
| BMI (kg/m2) | 23.27 (23.17–23.38) | 26.03 (25.85–26.21) | <0.001 |
| Smoking, % | <0.001 | ||
| Non-smoker | 64.8 (63.2–66.4) | 56.2 (53.7–58.6) | |
| Ex-smoker | 3.3 (2.8–3.8) | 5.9 (4.9–7.1) | |
| Current smoker | 31.9 (30.3–33.6) | 37.9 (35.5–40.4) | |
| Smoking amount (PYRs) | 18.13 (16.93–19.32) | 19.28 (17.83–20.73) | <0.001 |
| Metabolic syndrome, % | 12.6 (11.4–13.8) | 74.6 (72.1–77.0) | <0.001 |
| Diabetes mellitus, % | 1.8 (1.5–2.2) | 24.2 (22.2–26.2) | <0.001 |
| Hypertension, % | 15.5 (14.3–16.8) | 50.0 (47.3–52.7) | <0.001 |
| Pulmonary function test | |||
| FVC (L) | 3.56 (3.52–3.59) | 3.51 (3.45–3.56) | <0.001 |
| FEV1 (L) | 2.86 (2.83–2.89) | 2.78 (2.74–2.82) | <0.001 |
| FEV1 (%) | 92.62 (92.15–93.08) | 91.07 (90.44–91.70) | <0.001 |
| FEV1/FVC ratio | 0.80 (0.80–0.81) | 0.79 (0.79–0.80) | <0.001 |
| OLD, % | 8.5 (7.7–9.4) | 10.0 (8.8–11.4) | 0.060 |
| AST (IU/L) | 19.75 (19.50–20.01) | 27.22 (26.37–28.07) | <0.001 |
| ALT (IU/L) | 17.40 (17.09–17.71) | 33.89 (32.53–35.25) | <0.001 |
| LFSa | −1.83 (−1.86 to −1.80) | 0.63 (0.55–0.71) | <0.001 |
Notes: Values are presented as percentage and mean (95% CI) unless otherwise specified. OLD is defined as FEV1/FVC ratio <0.7.
a
LFS = 22.89 + 1.18 × metabolic syndrome + 0.45 × diabetes + 0.15 × fasting insulin + 0.04 × AST (IU/l) + 0.94 × AST/ALT ratio.
Abbreviations: NAFLD, non-alcoholic fatty liver disease; BMI, body mass index; PYRs, pack years; FVC, forced vital capacity; FEV1, forced expiratory volume; OLD, obstructive lung disease; AST, aspartate aminotransferase; ALT, alanine aminotransferase; LFS, liver fat score; CI, confidence interval.