Characteristics of the study population
| Total population n=3882 | No NAFLD n=2545 (65.6%) | NAFLD n=1337 (34.4%) | P value* | |
| Demographics | ||||
| Age (years) | 69.7±8.8 | 69.6±9.2 | 70.0±8.2 | 0.164 |
| Female (%) | 58.3 | 59.1 | 56.8 | 0.184 |
| Caucasian (%) | 97.6 | 97.4 | 98.0 | 0.458 |
| Education level (%) | ||||
| Low | 48.4 | 45.0 | 54.9 | <0.001 |
| Intermediate | 30.2 | 31.4 | 28.1 | |
| High | 21.3 | 23.6 | 17.0 | |
| Smoking status (%) | ||||
| Never | 36.1 | 38.3 | 31.8 | <0.001 |
| Past or current | 63.9 | 61.7 | 68.2 | |
| Alcohol (units/day) | 0.45 (0.05 to 1.20) | 0.45 (0.06 to 1.21) | 0.43 (0.05 to 1.19) | 0.422 |
| Physical activity† | 40.6 (15.7 to 77.6) | 43.8 (17.2 to 81.3) | 34.6 (13.5 to 70.0) | <0.001 |
| Physical examination | ||||
| BMI (kg/m2) | 26.9 (24.5 to 29.7) | 25.8 (23.7 to 28.0) | 29.3 (27.0 to 32.3) | <0.001 |
| Lean | 30.2 | 40.9 | 9.9 | <0.001 |
| Overweight | 69.7 | 59.1 | 90.1 | |
| Waist circumference (cm) | ||||
| Men | 98.2±10.6 | 95.0±9.1 | 104.1±10.5 | <0.001 |
| Women | 89.1±12.2 | 85.0±10.5 | 97.4±11.3 | <0.001 |
| Biochemistry | ||||
| AST (U/L) | 24 (21 to 28) | 24 (21 to 28) | 25 (21 to 29) | <0.001 |
| ALT (U/L) | 18 (15 to 24) | 17 (14 to 22) | 21 (16 to 29) | <0.001 |
| GGT (U/L) | 23 (17 to 34) | 21 (15 to 30) | 28 (20 to 39) | <0.001 |
| Platelets (×109/L) | 262 (223 to 305) | 260 (222 to 303) | 266 (225 to 310) | 0.031 |
| HOMA-IR | 2.6 (1.7 to 4.1) | 2.1 (1.5 to 3.1) | 4.1 (2.7 to 6.1) | <0.001 |
| Total cholesterol (mmol/L) | 5.4±1.1 | 5.5±1.1 | 5.4±1.1 | 0.002 |
| HDL-C (mmol/L) | 1.5±0.4 | 1.5±0.4 | 1.3±0.4 | <0.001 |
| Triglycerides (mmol/L) | 1.3 (1.0 to 1.7) | 1.2 (0.9 to 1.5) | 1.6 (1.2 to 2.1) | <0.001 |
| Comorbidities | ||||
| Metabolic syndrome | 51.9 | 40.8 | 73.0 | <0.001 |
| WC>88 cm (♀) or>120 cm(♂) | 43.2 | 29.1 | 69.9 | <0.001 |
| Triglycerides>150 mg/dL | 46.0 | 39.0 | 59.4 | <0.001 |
| HDL-C<40 mg/dL(♂) or 50 mg/dL(♀) | 44.7 | 38.3 | 56.7 | <0.001 |
| Blood pressure≥130/85 mm Hg | 84.3 | 80.5 | 91.5 | <0.001 |
| FPG>100 mg/dL | 41.5 | 31.1 | 61.2 | <0.001 |
| Diabetes mellitus (%) | 13.1 | 7.5 | 23.7 | <0.001 |
| Hypertension (%) | 74.0 | 68.9 | 83.7 | <0.001 |
| Dietary data (E%) | ||||
| Total kcal/day | 2031 (1620 to 2515) | 2052 (1642 to 2537) | 1996 (1579 to 2456) | 0.003 |
| Total protein | 15.6 (14.0 to 17.4) | 15.4 (13.8 to 17.2) | 16.0 (14.3 to 17.8) | <0.001 |
| Animal protein | 9.2 (7.5 to 11.2) | 9.0 (7.2 to 10.9) | 9.5 (7.9 to 11.6) | <0.001 |
| Vegetable protein | 6.3 (5.5 to 7.1) | 6.3 (5.5 to 7.1) | 6.2 (5.4 to 7.1) | 0.076 |
| Total fat | 31.9 (27.9 to 36.1) | 31.7 (27.8 to 35.9) | 32.4 (28.2 to 36.5) | 0.039 |
| Saturated fat | 11.5 (9.7 to 13.3) | 11.4 (9.7 to 13.2) | 11.6 (9.9 to 13.5) | 0.018 |
| MUFA | 10.7 (9.2 to 12.4) | 10.7 (9.1 to 12.3) | 10.8 (9.3 to 12.6) | 0.055 |
| PUFA | 6.4 (5.3 to 7.6) | 6.4 (5.4 to 7.6) | 6.4 (5.3 to 7.6) | 0.276 |
| Trans fatty acid | 0.51 (0.41 to 0.62) | 0.50 (0.41 to 0.61) | 0.53 (0.42 to 0.64) | 0.002 |
| Total carbohydrate | 46.2 (41.9 to 50.7) | 46.6 (42.2 to 51.0) | 45.5 (41.5 to 50.3) | <0.001 |
| Monosaccharide and disaccharide | 22.8 (18.2 to 27.7) | 23.2 (18.7 to 28.0) | 21.9 (17.5 to 26.9) | <0.001 |
| Polysaccharide | 22.7 (19.8 to 26.0) | 22.7 (19.7 to 26.0) | 22.7 (19.9 to 25.9) | 0.683 |
| Fibre | 2.6 (2.2 to 3.0) | 2.6 (2.2 to 3.1) | 2.6 (2.1 to 3.0) | 0.013 |
| Total alcohol | 1.4 (0.2 to 3.4) | 1.4 (0.2 to 3.4) | 1.3 (0.1 to 3.5) | 0.939 |
Pooled data based on 10 imputations represent % for categorical variables and for continuous variables mean±SD or median (P25 to P75).
*P value is based on t-test, Wilcoxon rank sum test, χ² test or Fisher’s exact test and is a comparison between the no NAFLD and NAFLD columns.
†Physical activity in metabolic equivalent task hours/week.
ALT, alanine aminotransferase; AST, aspartate aminotransferase; BMI, body mass index; FPG, fasting plasma glucose; GGT, gamma-glutamyl transferase; HDL-C, high-density lipoprotein cholesterol; HOMA-IR, homeostasis model assessment of insulin resistance; MUFA, mono-unsaturated fatty acid; NAFLD, non-alcoholic fatty liver disease; PUFA, poly-unsaturated fatty acid; WC, waist circumference.