Table 2.
Baseline Characteristics by Quintiles of Red Cell Distribution Width. The Tromsø Study
| Red cell distribution width | Quintile 1 | Quintile 2 | Quintile 3 | Quintile 4 | Quintile 5 |
|---|---|---|---|---|---|
| N | 5081 | 4702 | 4886 | 4900 | 6043 |
| Median, % (range) | 12.0 (10.7 to 12.2) | 12.4 (12.3 to 12.5) | 12.7 (12.6 to 12.8) | 13.0 (12.9 to 13.2) | 13.7 (13.3 to 30.5) |
| Age, y | 40.2 (12.0) | 43.4 (13.2) | 45.4 (13.9) | 48.8 (14.7) | 52.8 (15.8) |
| Systolic blood pressure, mm Hg | 130 (17) | 133 (19) | 134 (20) | 136 (21) | 139 (23) |
| Diastolic blood pressure, mm Hg | 75 (11) | 77 (12) | 78 (12) | 79 (12) | 80 (14) |
| Hypertension, %* | 32.2 (1306) | 33.3 (1469) | 31.9 (1614) | 31.2 (1843) | 32.7 (2719) |
| Body mass index, kg/m2 | 24.6 (3.4) | 25.0 (3.7) | 25.2 (3.7) | 25.3 (3.9) | 25.5 (4.3) |
| Total cholesterol, mmol/L | 5.7 (1.2) | 5.9 (1.3) | 6.0 (1.3) | 6.2 (1.3) | 6.3 (1.3) |
| High‐density lipoprotein cholesterol, mmol/L | 1.5 (0.4) | 1.5 (0.4) | 1.5 (0.4) | 1.5 (0.4) | 1.6 (0.4) |
| Triglycerides, mmol/L | 1.5 (1.1) | 1.5 (1.0) | 1.6 (1.1) | 1.5 (1.0) | 1.5 (1.0) |
| Daily smoking, % | 26.8 | 31.8 | 36.2 | 41.8 | 47 |
| Self‐reported diabetes, % | 1.9 | 1.8 | 2.1 | 1.3 | 1.1 |
| Hemoglobin (total), g/dL | 14.1 (1.1) | 14.1 (1.1) | 14.1 (1.1) | 14.1 (1.1) | 13.7 (1.4) |
| Hemoglobin (women), g/dL | 13.4 (0.8) | 13.4 (0.8) | 13.4 (0.9) | 13.4 (0.9) | 13.0 (1.2) |
| Hemoglobin (men), g/dL | 15.0 (0.8) | 14.9 (0.8) | 14.9 (0.9) | 14.8 (0.9) | 14.5 (1.1) |
| Mean corpuscular volume, fL | 89 (3.3) | 89 (3.5) | 89 (3.6) | 89 (3.8) | 88 (5.8) |
| Red blood cells, ×1012/L | 4.6 (0.4) | 4.7 (0.4) | 4.7 (0.4) | 4.6 (0.4) | 4.6 (0.4) |
| White blood cells, ×109/L | 6.9 (1.8) | 7.0 (1.9) | 7.1 (2.1) | 7.1 (2.0) | 7.3 (2.2) |
| Platelets, ×109/L | 251 (51) | 250 (52) | 250 (53) | 252 (55) | 260 (66) |
Age at baseline and age‐adjusted baseline characteristics by quintiles of red cell distribution width, expressed as means (with SD in parentheses) for continuous variables and percentages for dichotomous variables.
*
Defined as systolic blood pressure ≥140 mm Hg or diastolic blood pressure ≥90 mm Hg or self‐reported use of antihypertensive medication.