Table 3. Differences in metabolic parameters before and after a 6-month weight reduction intervention in participants with increased or decreased irisin levels.
| Variable | Increase in irisin | Decrease in irisin | ||||
|---|---|---|---|---|---|---|
| Before | After | P value | Before | After | P value | |
| Sex, male/female | 13 (4/9) | 9 (3/6) | ||||
| Age, yr | 48.2±15.0 | 43.1±17.8 | ||||
| Body weight, kg | 92.5±15.3 | 86.0±13.1 | <0.01 | 93.6±20.9 | 88.8±20.6 | <0.05 |
| Body mass index, kg/m2 | 36.8±5.0 | 34.0±3.7 | <0.01 | 37.0±5.2 | 35.2±5.7 | <0.05 |
| % Body fat, % | 48.2±10.4 | 43.2±7.8 | <0.05 | 43.7±9.0 | 45.1±8.0 | 0.45 |
| % Skeletal muscle, % | 49.5±5.4 | 53.4±6.7 | <0.01 | 49.5±4.9 | 51.9±4.5 | <0.01 |
| Skeletal muscle index | 7.6±1.3 | 7.5±1.2 | 0.15 | 7.9±1.2 | 7.8±1.1 | 0.69 |
| Leg strength, kg/kg | 1.3±0.3 | 1.2±0.2 | 0.11 | 1.5±0.4 | 1.7±0.3 | 0.20 |
| Exercise capacity | ||||||
| ATVO2, mL/min/kg | 11.1±1.7 | 12.0±1.6 | 0.14 | 11.1±2.1 | 12.5±2.4 | 0.07 |
| Peak VO2, mL/min/kg | 17.2±3.9 | 18.4±3.0 | 0.06 | 20.8±4.2 | 21.1±5.0 | 0.31 |
| Metabolic parameter | ||||||
| Visceral fat area, cm2 | 169.6±66.1 | 147.2±45.5 | <0.05 | 167.7±48.7 | 135.7±32.4 | <0.05 |
| Subcutaneous fat area, cm2 | 477.2±138.4 | 425.8±129.1 | <0.01 | 449.3±108.3 | 406.7±85.6 | 0.06 |
| HDL-C, mg/dL | 39.0±7.3 | 49.0±8.3 | <0.01 | 46.6±10.6 | 50.7±9.9 | <0.05 |
| LDL-C, mg/dL | 98.8±28.1 | 109.2±26.5 | <0.05 | 118.6±28.0 | 120.4±23.5 | 0.75 |
| Triglycerides, mg/dL | 152.1±53.6 | 122.7±42.8 | <0.05 | 128.9±43.8 | 152.7±63.1 | 0.23 |
| Fasting glucose, mg/dL | 97.3±10.5 | 92.4±8.3 | <0.01 | 96.1±11.1 | 93.3±7.6 | 0.33 |
| Fasting insulin, µU/mL | 11.1±4.0 | 9.7±4.8 | 0.20 | 17.8±11.0 | 16.4±8.2 | 0.52 |
| HOMA-IR, ×10-6 mol×IU×L-2 | 2.7±1.2 | 2.2±1.1 | 0.08 | 4.1±2.2 | 3.7±1.6 | 0.48 |
| HbA1c, % | 5.7±0.5 | 5.7±0.4 | 0.66 | 5.7±0.4 | 5.7±0.3 | 0.43 |
| Myokine | ||||||
| Serum irisin, ng/mL | 1.1±0.1 | 1.3±0.2 | <0.01 | 1.3±0.3 | 1.2±0.2 | <0.05 |
Values are presented as mean±standard deviation. Differences in metabolic parameters from before to after the intervention in each group were evaluated by paired t-test.
ATVO2, anaerobic threshold oxygen uptake; Peak VO2, peak oxygen uptake; HDL-C, high density lipoprotein cholesterol; LDL-C, low density lipoprotein cholesterol; HOMA-IR, homeostasis model assessment of insulin resistance; HbA1c, glycosylated hemoglobin.