Table 2.
Baseline characteristics of initial non-HTN participants according to baseline bilirubin quartiles
| Variable | Overall | STB quartiles | ||||
|---|---|---|---|---|---|---|
| 1 (Lowest) | 2 | 3 | 4 | P value | ||
| < 9.3 (μmol/L) | 9.3 ~ 11.8 (μmol/L) | 11.9 ~ 15.2 (μmol/L) | > 15.2 (μmol/L) | |||
| N = 1881 | n = 470 | n = 456 | n = 478 | n = 477 | ||
| Age (years) | 61.00 (59.00–66.00) | 62.00 (59.00–67.00) | 61.00 (59.25–66.00) | 61.00 (59.00–66.00) | 61.00 (59.00–65.00) | 0.107 |
| Length of follow-up (Person-years) | 3.68 ± 1.69 | 3.54 ± 1.73 | 3.86 ± 1.67 | 3.61 ± 1.72 | 3.71 ± 1.61 | 0.025 |
| Male (n, %) | 823 (43.75) | 189 (40.21) | 174 (38.16) | 212 (44.35) | 248 (51.99) | < 0.001 |
| WC (cm) | 81.00 (75.00–88.00) | 81.00 (74.00–87.00) | 81.00 (76.00–88.00) | 81.00 (75.00–87.00) | 80.00 (74.00–87.00) | 0.211 |
| BMI (kg/m2) | 22.26 (20.45–24.46) | 22.15 (20.44–24.34) | 22.66 (20.95–24.94) | 22.21 (20.44–24.44) | 22.04 (20.03–24.25) | 0.007 |
| SBP (mm Hg) | 127.00 (117.00–138.00) | 127.00 (116.75–138.00) | 129.00 (118.00–139.00) | 125.50 (116.00–137.00) | 127.00 (117.50–137.50) | 0.094 |
| DBP (mm Hg) | 78.00 (72.00–84.00) | 77.00 (71.00–84.00) | 78.00 (72.00–85.00) | 78.00 (72.00–84.00) | 78.00 (72.00–85.00) | 0.389 |
| Leukocyte (× 109/L) | 5.90 (5.10–7.01) | 5.90 (5.29–7.10) | 5.80 (5.00–7.10) | 6.00 (5.20–7.10) | 5.96 (4.90–7.90) | 0.169 |
| Platelet (× 109/L) | 217.00 (190.00–252.00) | 225.00 (201.00–261.25) | 217.00 (190.25–251.00) | 215.00 (185.00–250.25) | 212.00 (184.00–242.00) | < 0.001 |
| Hemoglobin (g/L) | 135.00 (126.00–144.00) | 132.00 (124.75–142.00) | 134.00 (126.00–142.00) | 136.00 (126.75–145.00) | 138.00 (129.50–147.00) | < 0.001 |
| FPG (mmol/L) | 4.99 (4.50–5.60) | 4.94 (4.50–5.60) | 4.90 (4.40–5.50) | 4.99 (4.67–5.60) | 5.10 (4.50–5.70) | 0.278 |
| ALT (U/L) | 20.90 (16.30–27.50) | 19.20 (14.68–25.63) | 20.70 (16.40–27.10) | 21.90 (17.00–29.25) | 21.90 (17.65–27.50) | < 0.001 |
| AST (U/L) | 21.00 (18.00–24.10) | 19.95 (17.30–24.00) | 20.00 (17.93–23.30) | 21.00 (18.20–25.00) | 21.00 (19.00–25.00) | < 0.001 |
| Albumin (g/L) | 44.50 (42.90–46.00) | 44.45 (42.50–45.93) | 44.20 (42.60–46.00) | 44.60 (42.90–46.10) | 44.80 (43.30–46.10) | 0.024 |
| CB (μmol/L) | 3.20 (2.20–4.50) | 2.40 (1.60–3.10) | 3.10 (2.30–3.70) | 3.50 (2.48–4.50) | 4.50 (2.85–5.80) | < 0.001 |
| UCB (μmol/L) | 8.50 (5.90–11.50) | 5.00 (3.70–6.00) | 7.40 (6.50–8.38) | 9.90 (8.60–11.13) | 14.00 (11.60–16.75) | < 0.001 |
| SCr (μmol/L) | 62.80 (51.70–75.80) | 63.70 (51.48–77.33) | 60.05 (48.10–73.75) | 62.55 (52.43–75.43) | 64.40 (54.00–77.00) | 0.001 |
| TC (mmol/L) | 5.03 (4.40–5.71) | 4.94 (4.20–5.65) | 5.07 (4.35–5.70) | 5.07 (4.43–5.72) | 5.04 (4.46–5.76) | 0.135 |
| TG (mmol/L) | 1.04 (0.77–1.48) | 1.08 (0.81–1.62) | 1.07 (0.78–1.46) | 1.03 (0.77–1.49) | 0.99 (0.72–1.39) | 0.007 |
| T2DM (n, %) | 178 (9.46) | 52 (11.06) | 42 (9.21) | 43 (8.81) | 41 (8.78) | 0.510 |
| Hyperuricemia (n, %) | 468 (24.88) | 82 (17.44) | 107 (23.46) | 142 (29.71) | 137 (28.78) | < 0.001 |
| Marriage (n, %) | 0.976 | |||||
| Married | 1638 (87.08) | 405 (86.17) | 395 (86.62) | 421 (88.08) | 417 (87.42) | |
| Widowed | 229 (12.17) | 61 (12.98) | 58 (12.72) | 53 (11.09) | 57 (11.95) | |
| Unspecified | 14 (0.74) | 4 (0.85) | 3 (0.66) | 4 (0.84) | 3 (0.63) | |
| Smoking Status (n, %) | 0.069 | |||||
| Non-smoker | 1331 (70.76) | 335 (71.28) | 335 (73.46) | 340 (71.13) | 321 (67.30) | |
| Former Smoker | 53 (2.82) | 9 (1.91) | 10 (2.19) | 11 (2.30) | 23 (4.82) | |
| Current Smoker | 491 (26.10) | 125 (26.60) | 110 (24.12) | 124 (25.94) | 132 (27.67) | |
| Drinking Status (n, %) | 0.019 | |||||
| Non-drinker | 1560 (82.93) | 396 (84.26) | 388 (85.09) | 402 (84.10) | 374 (78.41) | |
| Current Drinker | 311 (16.53) | 70 (14.89) | 67 (14.69) | 73 (15.27) | 101 (21.74) | |
| Exercise Frequency (n, %) | 0.013 | |||||
| Low | 1102 (58.59) | 307 (65.32) | 257 (56.36) | 269 (56.28) | 269 (56.39) | |
| Medium | 322 (17.12) | 55 (11.70) | 87 (19.08) | 89 (18.62) | 91 (19.08) | |
| High | 457 (24.30) | 108 (22.98) | 112 (24.56) | 120 (25.10) | 117 (24.53) | |
| Incident HTN (n, %) | 435 (6.29) | 81 (4.87) | 104 (5.92) | 121 (7.01) | 129 (7.28) | 0.018 |
Normally distributed variables are presented as mean ± SD, skewed variables as median (interquartile range), and categorical variables as n (%). Incidence rate was calculated as the number of hypertension incident cases divided by 100 person-years of follow-up. Continuous variables were compared using one-way ANOVA or Kruskal–Wallis test depending on distribution. Pearson’s χ2 tests were used to compare categorical values
HTN, hypertension; WC, waist circumference; BMI, body mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure; FPG, fasting plasm blood; ALT, alanine aminotransferase; AST, aspartate aminotransferase; STB, serum total bilirubin; CB, conjugated bilirubin; UCB, unconjugated bilirubin; SCr, serum creatinine; TC, total cholesterol; TG, triglyceride; T2DM, type 2 diabetes mellitus