Table 1.
Participant characteristics and study conditions of those with and without NAFLD
| All (n = 60) | Normal liver fat (n = 30) | Hepatic steatosis (n = 29) | p | |
|---|---|---|---|---|
| Age (years) | 25.9 (22.9–36.4) | 23.8 (21.2–27.2) | 31.02 (25.1–43.4) | <0.001† |
| Gender (male) | 37 (62%) | 19 (63%) | 18 (62%) | 0.920 |
| Weight (kg) | 81.9 (18.6) | 70.7 (13.6) | 91.7 (14.8) | <0.001∗ |
| BMI (kg/m2) | 27.9 (6.8) | 22.4 (21.0–25.0) | 30.4 (26.0–35.9) | <0.001† |
| Waist circumference (cm) | 90.4 (16.9) | 76.8 (72.5–83.8) | 101.4 (89.8–110.2) | <0.001† |
| Body fat (%)a | 30.6 (12.6) | 23.9 (9.6) | 37.4 (11.8) | <0.001∗ |
| Hepatic fat (%)b | 5.5 (4.6–7.1) | 4.6 (4.0–5.1) | 7.1 (6.2–8.5) | <0.001† |
| Pre-cold SCV PDFF (%) | 72.4 (8.0) | 67.9 (7.0) | 76.7 (6.2) | <0.001∗ |
| Absolute cold-induced decline in SCV PDFF (%) | 3.0 (2.4) | 3.6 (2.2) | 2.5 (2.4) | 0.082 |
| Cold-induced percentage decline in SCV PDFF (%) | 4.4 (3.9) | 4.7 (2.7–8.0) | 2.5 (1.2–5.7) | 0.019† |
| VAT (cm2)c | 30.3 (26.1) | 8.7 (5.2,17.2) | 58.6 (22.7–64.6) | <0.001† |
| SAT (cm2)c | 99.3 (68.1) | 43.2 (29.3–68.5) | 150.1 (87.2–188.3) | <0.001† |
| Fasting plasma glucose (mmol/L) | 4.7 (4.4–4.9) | 4.6 (4.1–4.8) | 4.8 (4.6–5.1) | 0.005† |
| 2 h glucose (mmol/L)d | 4.4 (3.8–5.8) | 4.4 (1.3) | 5.00 (1.4) | 0.299 |
| HbA1c (%) | 5.2 (4.9–5.5) | 5.1 (4.9–5.3) | 5.3 (4.9–5.6) | 0.112 |
| Total cholesterol (mmol/L) | 4.4 (0.8) | 4.1 (0.6) | 4.6 (0.8) | 0.005∗ |
| Triglycerides (mmol/L) | 0.8 (0.6–1.2) | 0.8 (0.2) | 1.3 (0.7) | <0.001∗ |
| HDL-C (mmol/L) | 1.3 (0.3) | 1.4 (0.3) | 1.2 (0.3) | 0.052 |
| LDL-C (mmol/L) | 2.6 (0.7) | 2.3 (0.6) | 2.8 (0.6) | 0.004∗ |
| Non-HDL-C (mmol/L) | 3.1 (0.8) | 2.7 (0.6) | 3.4 (0.8) | <0.001∗ |
| Systolic blood pressure (mm Hg) | 111.4 (12.1) | 105.6 (10.7) | 116.2 (9.9) | <0.001∗ |
| Diastolic blood pressure (mm Hg) | 74.4 (9.8) | 70.7 (9.4) | 77.8 (8.9) | 0.004∗ |
| AST (U/L) | 18.5 (16.0–21.0) | 18.0 (16.0–21.0) | 19.0 (16.0–25.5) | 0.326 |
| ALT (U/L) | 20.0 (15–25.8) | 16.5 (13.0–21.5) | 25.0 (19.0–35.5) | <0.001† |
| GGT (U/L) | 18.5 (14.0–25.0) | 14.5 (11.0–19.0) | 20.0 (18.0–29.5) | 0.001† |
| Outdoor temperature 1 h before visit 2 (°C) | 7.18 (10.0) | 4.3 (7.7) | 10.5 (11.2) | 0.015∗ |
| Shivering intensity (% MVC)e | 1.95 (1.0–2.9) | 2.3 (1.3–3.5) | 1.2 (0.8–2.6) | 0.017† |
| ΔOutlet-inlet of the suit (°C)f | 1.6 (0.2) | 1.6 (0.2) | 1.5 (0.2) | 0.671 |
Categorical variables are presented as n (%), and continuous variables are presented as mean (SD) for normally distributed variables and median (interquartile range) for non-normally distributed variables. BMI, body mass index; SCV, supraclavicular; PDFF, proton density fat fraction; VAT, visceral adipose tissue; SAT, subcutaneous adipose tissue; HbA1c, hemoglobin A1c; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; AST, aspartate aminotransferase; ALT, alanine aminotransferase; GGT, gamma-glutamyl transferase.
p < 0.05, independent-samples t test; †p < 0.05, Mann-Whitney U test. Differences in gender were assessed using the chi-square test.
One participant was above the weight threshold for body composition analysis via dual-energy X-ray absorptiometry (DEXA).
No liver scan was performed for one participant who did not fit inside the scanner.
No abdominal volume data were available for four participants (n = 2, acquisition error; n = 1, did not fit inside the scanner; n = 1, motion issues).
Two-hour glucose was not performed in 29 participants (n = 2, fainted during baseline bloodwork; n = 1, known type 2 diabetes; n = 26, glucose solution was later recalled, so the test was not reliable).
Motion artifacts were present for one participant.
No outlet-inlet data were available for five participants (n = 4, data were not acquired; n = 1, error in the data acquisition).