Table 1.
Characteristics of the study population stratified by serum TSH levels.
| TSH in Reference Range (n = 7003) |
Low TSH (n = 596) |
High TSH (n = 334) |
|
|---|---|---|---|
| Study | |||
| SHIP-START-2 | 26.2% | 37.6% | 18.0% |
| SHIP-TREND-0 | 50.1% | 58.4% | 45.5% |
| BASE-II | 23.7% | 4.0% | 36.5% |
| Age; years | 54.6 (15.7) | 60.7 (13.2) | 51.8 (17.7) |
| Females | 50.3% | 54.0% | 63.5% |
| Smoking status | |||
| Never | 39.8% | 36.7% | 40.7% |
| Former | 37.7% | 43.1% | 34.1% |
| Current | 22.6% | 20.1% | 25.2% |
| Body mass index; kg/m2 | 27.6 (5.0) | 28.3 (5.1) | 27.2 (5.7) |
| Waist circumference; cm | 92 (14) | 93 (14) | 90 (15) |
| Hypertension | 48.9% | 61.1% | 39.4% |
| Type 2 diabetes | 9.5% | 13.8% | 8.4% |
| HDL-cholesterol; mmol/L | 1.47 (0.40) | 1.45 (0.39) | 1.53 (0.43) |
| LDL-cholesterol; mmol/L | 3.31 (0.95) | 3.36 (0.98) | 3.30 (1.03) |
| TSH; mIU/L | 1.45 (0.72) | 0.31 (0.14) | 6.51 (7.82) |
| fT3; pmol/L | 4.73 (0.88) | 4.78 (0.99) | 4.69 (0.95) |
| fT4; pmol/L | 14.0 (2.3) | 15.1 (3.2) | 13.6 (3.0) |
| Thyroid medication | 9.7% | 25.7% | 24.3% |
| Serum creatinine; µmol/L | 78 (17) | 77 (19) | 79 (17) |
| eGFR (CKD-EPI); mL/min | 87 (18) | 84 (19) | 86 (19) |
| eGFR (CKD-EPI) < 60 mL/min | 6.9% | 11.7% | 8.4% |
| eGFR (FAS); mL/min | 84 (22) | 80 (23) | 81 (21) |
| eGFR (FAS) < 60 mL/min | 12.7% | 19.6% | 14.7% |
| Urea; mmol/L | 5.1 (1.5) | 5.4 (1.9) | 5.0 (1.4) |
| Uric acid; µmol/L | 294 (81) | 292 (82) | 285 (81) |
| ACR ≥ 30 mg/g | 11.9% | 15.8% | 14.1% |
TSH reference limits according to [17]; ACR, urinary albumin–creatinine ratio. Data are expressed as mean and standard deviation for continuous variables and as percentage for categorical variables.