Table 1.
Sample characteristics
| Clinical variables | Men (N=1837) | Women (N=2140) |
|---|---|---|
| Age, years | 40±9 | 40±9 |
| Height, m | 1.78±0.07 | 1.64±0.06 |
| Weight, kg | 88.1±15.8 | 69.5±16.4 |
| Body mass index, kg/m2 | 27.8±4.6 | 25.8±6.0 |
| Systolic blood pressure, mmHg | 121±13 | 113±14 |
| Diastolic blood pressure, mmHg | 78±9 | 73±9 |
| Hypertension, % | 20 | 12 |
| Diabetes mellitus, % | 3 | 2 |
| Smoking, % | 16 | 15 |
| Alcohol consumption, ounces per month | 13.6±18 | 5.9±8.0 |
| Glomerular filtration rate, ml/min/1.73m2 | 99.7±17.2 | 99.5±18.8 |
| Total cholesterol, mg/dl | 193±37 | 185±34 |
| HDL cholesterol, mg/dl | 47±12 | 61±16 |
| LDL cholesterol, mg/dl | 120±31 | 104±30 |
| Triglycerides (median, 25th–75th percentile), mg/dl | 107 (72–160) | 80 (59–114) |
| HOMA-IR | 1.20±1.02 | 0.97±0.75 |
| Insulin resistance, % | 31 | 20 |
| IGF-1, ng/ml | 128±39 | 129±45 |
| IGFBP-3, ng/ml | 2905±1079 | 3097±1096 |
| IGF-1:IGFBP-3 ratio (median, 25th–75th percentile) | 0.044 (0.034–0.057) | 0.042 (0.032–0.054) |
Values are mean±SD unless otherwise indicated.
HDL, high density lipoprotein; LDL, low density lipoprotein; HOMA-IR, homeostatic model assessment of insulin resistance, calculated using the equation HOMA-IR = (FPI × FPG)/22.5 where FPI = fasting plasma insulin in mU/l and FPG = fasting plasma glucose in mmol/l25; The presence of insulin resistance was defined as HOMA-IR at or above the 75th percentile of 1.25; IGF-1, insulin-like growth factor-1; IGFBP-3, insulin-like growth factor binding protein-3; IQR, interquartile range.
To calculate the molar ratio of IGF-1 to IGFBP-3 using molar weights of 7.65 kDa for IGF-1 and 30.5 kDa45 for IGFBP-3, multiply ratio values by 3.987.