Table 1. Baseline characteristics of study participants by quartile of serum direct bilirubin (N = 5,900).
| Overall | Direct bilirubin | P value trend | ||||
| Quartile 1 | Quartile 2 | Quartile 3 | Quartile 4 | |||
| Number | 5900 | 2196 | 1,319 | 924 | 1461 | |
| Direct bilirubin, mg/dL * | 0.44 (0.21) | 0.25 (0.07) | 0.4 (0) | 0.5 (0) | 0.73 (0.16) | |
| Range | 0–1.7 | 0– | 0.4– | 0.5– | 0.6–1.7 | |
| Age, years * | 36.8 (4.9) | 37.0 (5.1) | 36.9 (4.9) | 36.6 (4.8) | 36.5 (4.7) | 0.004 |
| BMI, kg/m2 * | 22.9 (2.4) | 23.2 (2.4) | 22.9 (2.4) | 22.7 (2.4) | 22.4 (2.3) | <0.001 |
| Current smoker, % | 43.4 | 48.2 | 42.6 | 42.9 | 37.0 | <0.001 |
| Alcohol intake, % ‡ | 27.5 | 27.3 | 27.1 | 30.8 | 26.2 | 0.95 |
| Regular exercise, % § | 51.4 | 49.8 | 50.6 | 54.3 | 52.8 | 0.03 |
| Hypertension, % | 12.1 | 12.3 | 13.0 | 13.1 | 10.6 | 0.20 |
| Metabolic syndrome, % | 4.8 | 6.8 | 4.6 | 4.6 | 2.2 | <0.001 |
| Diabetes mellitus, % | 0.6 | 0.5 | 0.7 | 0.7 | 0.8 | 0.26 |
| Cardiovascular dis., % | 0.1 | 0.1 | 0.1 | 0.2 | 0.1 | 0.82 |
| Malignancy, % | 0.2 | 0.1 | 0.3 | 0.2 | 0.3 | 0.44 |
| Lipid lowering agent, % | 0.4 | 0.5 | 0.5 | 0.3 | 0.2 | 0.14 |
| Hemoglobin, g/dL | 15.0 (0.9) | 14.9 (0.9) | 15.0 (0.8) | 15.1 (0.8) | 15.2 (0.8) | <0.001 |
| Leukocyte, ×103/µL | 5.8 (1.4) | 6.0 (1.4) | 5.8 (1.4) | 5.7 (1.4) | 5.5 (1.3) | <0.001 |
| Systolic BP, mmHg * | 114.1 (12.2) | 114.1 (12.2) | 114.3 (12.0) | 114.3 (12.3) | 113.7 (12.3) | 0.38 |
| Diastolic BP, mmHg * | 73.8 (9.7) | 73.7 (9.7) | 74.3 (9.6) | 73.8 (10.0) | 73.6 (9.6) | 0.62 |
| Glucose, mg/dL * | 90.2 (11.6) | 91.7 (10.4) | 90.3 (11.4) | 90.0 (10.9) | 88.1 (13.4) | <0.001 |
| Uric acid, mg/dL * | 5.84 (1.07) | 5.83 (1.07) | 5.85 (1.07) | 5.86 (1.05) | 5.83 (1.09) | 0.95 |
| Tot. cholesterol, mg/dL * | 194.7 (32.2) | 201.3 (32.4) | 196.2 (32.5) | 191.2 (31.3) | 185.7 (29.6) | <0.001 |
| LDL-C, mg/dL * | 116.3 (27.7) | 120.8 (27.7) | 117.4 (27.7) | 114.0 (27.6) | 110.0 (26.5) | <0.001 |
| HDL-C, mg/dL * | 53.4 (11.6) | 51.1 (11.0) | 53.2 (11.8) | 54.0 (11.1) | 56.8 (11.7) | <0.001 |
| Triglycerides, mg/dL † | 109.0 (82.0–150.0) | 122.0 (90.0–166.0) | 113.0 (84.0–153.0) | 104.0 (80.0–142.0) | 96.0 (74.0–128.0) | <0.001 |
| Total bilirubin, mg/dL | 1.18 (0.48) | 0.80 (0.20) | 1.07 (0.18) | 1.28 (0.21) | 1.76 (0.48) | <0.001 |
| Indirect bilirubin, mg/dL | 0.73 (0.31) | 0.55 (0.18) | 0.67 (0.18) | 0.78 (0.21) | 1.03 (0.37) | <0.001 |
| Albumin, g/dL | 4.43 (0.19) | 4.43 (0.19) | 4.43 (0.19) | 4.43 (0.19) | 4.43 (0.19) | 0.59 |
| ALT, IU/L † | 20.0 (16.0–25.0) | 21.0 (17.0–27.0) | 21.0 (17.0–26.0) | 19.0 (16.0–25.0) | 19.0 (16.0–23.0) | <0.001 |
| AST, IU/L † | 21.0 (19.0–24.0) | 21.0 (19.0–24.0) | 21.0 (19.0–24.0) | 21.0 (19.0–24.0) | 21.0 (18.0–24.0) | 0.01 |
| GGT, IU/L † | 20.0 (15.0–27.0) | 21.0 (16.0–28.0) | 20.0 (15.0–28.0) | 20.0 (15.0–26.0) | 19.0 (15.0–25.0) | <0.001 |
| ALP, IU/L † | 54.0 (47.0–63.0) | 55.0 (47.0–64.0) | 54.0 (47.0–63.0) | 53.0 (47.0–62.0) | 53.0 (46.0–62.0) | <0.001 |
| hsCRP, mg/L † | 0.40 (0.20–0.80) | 0.50 (0.20–1.00) | 0.40 (0.20–0.80) | 0.40 (0.20–0.70) | 0.30 (0.20–0.60) | <0.001 |
| Insulin, µU/dL † | 6.33 (5.10–8.20) | 6.89 (5.36–8.99) | 6.41 (5.17–8.20) | 6.03 (4.92–7.60) | 5.88 (4.83–7.46) | <0.001 |
| HOMA2-IR † | 0.82 (0.66–1.07) | 0.90 (0.70–1.17) | 0.83 (0.67–1.07) | 0.78 (0.64–1.00) | 0.76 (0.63–0.96) | <0.001 |
Data are.
*
means (standard deviation),
†
medians (interquartile range), or percentages.
Abbreviations: ALT, alanine aminotransferase; AST, aspartate aminotransferase; BMI, body mass index; BP, blood pressure; GGT, gamma-glutamyltranspeptidase; ALP, alkaline phosphatase; HDL-C, high-density lipoprotein-cholesterol; hsCRP, high sensitivity C-reactive protein; HOMA2-IR, homeostasis model assessment 2 of insulin resistance; LDL-C: low-density lipoprotein-cholesterol.
‡
≥20 g of ethanol per day.
§
≥1 time/week.