Table 1.
Baseline characteristics by quintile of serum retinol a(all reported P-values are two-sided at type I error rate of 0.05).
| Quintile of serum retinol | |||||
|---|---|---|---|---|---|
| Quintile 1 (n = 5,815) | Quintile 2 (n = 5,874) | Quintile 3 (n = 5,741) | Quintile 4 (n = 5,840) | Quintile 5 (n = 5,834) | |
| Serum retinol (µg/L) | 424 (52.5) | 516 (18.7) | 577 (17.1) | 642 (22.3) | 781 (93.4) |
| Age (y) | 58.1 (5.2) | 57.5 (5.1) | 57.2 (5.0) | 56.8 (5.0) | 56.4 (4.9) |
| Cigarettes/d | 20 (8) | 20 (8) | 20 (9) | 21 (9) | 21 (9) |
| Duration of smoking (y) | 37.3 (8.3) | 36.6 (8.3) | 35.9 (8.3) | 35.2 (8.6) | 34.7 (8.6) |
| Systolic blood pressure (mm Hg) | 140 (20) | 141 (19) | 141 (19) | 142 (19) | 145 (20) |
| Diastolic blood pressure (mm Hg) | 86 (11) | 87 (11) | 87 (11) | 88 (11) | 90 (11) |
| Serum total cholesterol (mmol/L) | 5.8 (1.1) | 6.1 (1.1) | 6.3 (1.1) | 6.4 (1.1) | 6.6 (1.2) |
| Serum HDL cholesterol (mmol/L) | 1.17 (0.30) | 1.18 (0.31) | 1.19 (0.31) | 1.20 (0.32) | 1.24 (0.35) |
| Serum beta-carotene (µg/L) | 210 (168) | 218 (180) | 221 (188) | 215 (178) | 194 (204) |
| BMI (kg/m2) | 25.5 (4.0) | 26.1 (3.8) | 26.3 (3.8) | 26.5 (3.7) | 26.9 (3.7) |
| Education (%, >elementary school) | 18.2 | 18.2 | 20.5 | 22.6 | 25.7 |
| Physically active (%) | 17.7 | 21.2 | 21.4 | 22.5 | 21.3 |
| History of CVD (%)b | 40.3 | 40.3 | 39.3 | 41.2 | 46.2 |
| History of diabetes mellitus (%) | 5.0 | 4.3 | 3.8 | 3.9 | 4.2 |
| Vitamin A supplement use (%) | 8.6 | 9.1 | 10.2 | 10.9 | 13.0 |
| Vitamin E supplement use (%) | 8.0 | 9.2 | 10.1 | 10.8 | 12.7 |
| Daily dietary intake | |||||
| Energy (kcal) | 2,666 (765) | 2,697 (759) | 2,698 (739) | 2,711 (753) | 2,672 (751) |
| Fat (triacylglycerol, g) | 106 (37) | 107 (37) | 107 (36) | 106 (36) | 103 (36) |
| Alcohol (g ethanol) | 13.5 (19.1) | 14.5 (18.6) | 16.8 (20.2) | 19.8 (21.9) | 25.4 (25.3) |
| Vitamin A (mg) | 1.78 (1.05) | 1.83 (1.07) | 1.87 (1.10) | 1.91 (1.07) | 1.94 (1.12) |
| Vitamin E (mg) | 12.2 (6.1) | 12.1 (5.8) | 12.0 (5.7) | 12.1 (5.6) | 11.8 (5.5) |
| Fruit (g) | 127 (101) | 130 (101) | 129 (103) | 130 (99) | 129 (106) |
| Vegetables (g) | 107 (70) | 110 (69) | 114 (70) | 118 (72) | 118 (72) |
| Red meat (g) | 70 (34) | 71 (35) | 72 (34) | 72 (33) | 72 (34) |
aValues are means with standard deviation unless otherwise indicated. ANOVA test for continuous variables and Chi-square test for categorical variables. All P value < 0.0001, with exception of fruit intake (P value > 0.05).
bCVD, cardiovascular disease; includes a history of deep vein thrombosis, superficial venous thrombosis, lung infarction or embolus, hypertension, arterial obstruction, stroke, heart arrhythmia, enlarged heart, valvular heart disease, myocardial infarction, coronary heart disease, and heart failure.