Table 1.
Baseline characteristics of study participants by quartiles of hematocrit
| Hematocrit Q1 | Hematocrit Q2 | Hematocrit Q3 | Hematocrit Q4 | Hematocrit Q5 | P for trend | |
|---|---|---|---|---|---|---|
|
| ||||||
| N | 18,447 | 18,503 | 18,611 | 19,190 | 18,548 | |
| Age, years | 55.21±13.21 | 52.53±12.33 | 51.16±12.08 | 50.20±12.09 | 48.83±12.09 | <0.001 |
| Men, n (%) | 14,613 (79.22) | 14,542 (78.56) | 14,716 (79.07) | 15,426 (80.39) | 14,629 (78.87) | 0.23 |
| Current smoking, n (%) | 4,918 (26.22) | 5,723 (30.93) | 6,082 (32.68) | 6,742 (35.13) | 7,034 (37.92) | <0.001 |
| Current drinking, n (%) | 5,346 (28.98) | 6,137 (33.17) | 6,662 (35.80) | 7,242 (37.74) | 7,846 (42.43) | <0.001 |
| Body mass index, kg/m2 | 24.28±3.54 | 24.76±3.45 | 25.08±3.44 | 25.34±3.42 | 25.66±3.47 | <0.001 |
| Hypertension, n (%) | 7,552 (40.94) | 7,846 (42.40) | 8,090 (43.47) | 8,739 (45.54) | 8,307 (44.79) | <0.001 |
| Diabetes mellitus, n (%) | 1,425 (7.72) | 1,593 (8.61) | 1,569 (8.43) | 1,892 (9.86) | 1,940 (10.46) | <0.001 |
| Dyslipidemia, n (%) | 5,641 (30.58) | 6,178 (33.39) | 6,512 (34.99) | 6,956 (36.25) | 6,890 (37.15) | <0.001 |
| Atrial fibrillation, n (%) | 89 (0.48) | 68 (0.37) | 69 (0.37) | 82 (0.43) | 90 (0.49) | 0.66 |
| SBP, mmHg | 129.98±21.12 | 130.45±20.71 | 130.77±20.51 | 131.56±20.80 | 131.19±21.13 | <0.001 |
| DBP, mmHg | 81.64±11.51 | 83.05±11.56 | 83.64±11.53 | 84.43±11.82 | 84.53±12.12 | <0.001 |
| FPG, mmol/L | 5.32±1.58 | 5.42±1.63 | 5.44±1.57 | 5.55±1.78 | 5.55±1.80 | <0.001 |
| TC, mmol/L | 4.77±1.14 | 4.87±1.14 | 4.94±1.15 | 5.03±1.14 | 5.08±1.15 | <0.001 |
| LDL, mmol/L | 2.15±1.03 | 2.29±0.97 | 2.38±0.92 | 2.44±0.86 | 2.42±0.78 | <0.001 |
| HDL, mmol/L | 1.57±0.43 | 1.54±0.41 | 1.54±0.41 | 1.55±0.39 | 1.57±0.39 | 0.58 |
| TGs, mmol/L | 1.54±1.35 | 1.63±1.40 | 1.69±1.39 | 1.75±1.39 | 1.76±1.37 | <0.001 |
| EGFR, mL/min per 1.73 m2 | 82.87±29.74 | 83.18±25.22 | 82.43±23.25 | 81.39±25.92 | 79.37±24.30 | <0.001 |
Notes: Hematocrit levels were classified into sex-specific quartiles (men: Q1, <41.5%; Q2, 41.6%–44.0%; Q3, 44.0%–45.9%; Q4, 46.0%–48.5%; and Q5, >48.6%; women: Q1, <36.6%; Q2, 36.7%–38.8%; Q3, 38.9%–40.7%; Q4, 40.7%–43.1%; and Q5, >43.2%).
Abbreviations: EGFR, EGF receptor; FPG, fasting plasma glucose; HDL, high-density lipoprotein; LDL, low-density lipoprotein; TC, total cholesterol; TG, triglyceride; Q, quintile.