Table 1.
Characteristics of the study population at baseline stratified by quartiles of TNF-α
| TNF-α quartiles | 1 | 2 | 3 | 4 | Pa |
|---|---|---|---|---|---|
| n | 386 | 401 | 385 | 386 | |
| TNF-α (pg/ml) | 2.2 (0.02) | 3.2 (0.01) | 4.0 (0.01) | 5.9 (0.09) | |
| Demographics | |||||
| Age (yr) | 53.6 (0.4) | 55.3 (0.4) | 55.6 (0.4) | 57.9 (0.4) | <0.0001 |
| Gender (male/female, %) | 41/59 | 47/53 | 45/55 | 45/55 | NS |
| Ethnicity, n (%) | <0.0001 | ||||
| Non-Hispanic whites | 130 (34) | 164 (41) | 149 (39) | 139 (36) | |
| African-American | 185 (48) | 116 (29) | 82 (21) | 58 (15) | |
| Hispanic | 71 (18) | 121 (30) | 154 (40) | 189 (49) | |
| Smoking (never/former/current, %) | 45/39/18 | 45/37/18 | 45/37/17 | 40/43/18 | NS |
| Obesity | |||||
| BMI (kg/m2) | 28.0 (0.3) | 29.0 (0.3) | 30.3 (0.3) | 30.6 (0.3) | <0.0001 |
| Waist circumference (cm) | 89.0 (0.6) | 92.2 (0.6) | 95.9 (0.7) | 96.8 (0.7) | <0.0001 |
| Hypertension (%, yes/no) | 31/69 | 37/63 | 41/59 | 46/54 | <0.0001 |
| Glucose/insulin | |||||
| Fasting glucose (mg/dl) | 113.8 (2.1) | 119.6 (2.5) | 131.1 (2.9) | 128.8 (2.5) | <0.0001 |
| Two-hour glucose | 160.2 (4.6) | 178.1 (5.1) | 204.9 (5.7) | 204.1 (5.6) | <0.0001 |
| Fasting insulin (μU/ml) | 15.9 (0.9) | 16.3 (0.8) | 19.9 (0.8) | 21.4 (0.6) | <0.0001 |
| Two-hour insulin | 82.4 (4.0) | 95.7 (4.8) | 101.7 (4.4) | 120.5 (5.3) | <0.0001 |
| Proinsulin (pmol/liter) | 7.1 (0.7) | 8.4 (0.5) | 11.1 (0.6) | 14.1 (0.9) | <0.0001 |
| Proinsulin/insulin | 0.50 (0.03) | 0.67 (0.08) | 0.69 (0.04) | 0.68 (0.03) | <0.05 |
| SI (×104/min−1 × μU−1 × ml−1) | 2.1 (0.1) | 1.9 (0.1) | 1.3 (0.09) | 1.2 (0.09) | <0.0001 |
| AIR (μU/ml) | 52.5 (2.8) | 52.8 (2.6) | 52.0 (2.4) | 56.1 (2.8) | NS |
| AIR (adjusted for SI) | 53.8 (2.7) | 54.5 (2.7) | 52.0 (2.7) | 55.2 (2.7) | NS |
| Lipids | |||||
| Total cholesterol (mg/dl) | 209.5 (1.9) | 212.9 (2.4) | 217.0 (2.2) | 211.3 (2.2) | NS |
| LDL (mg/dl) | 141.8 (1.8) | 141.6 (1.7) | 144.1 (1.9) | 137.7 (1.9 | NS |
| HDL (mg/dl) | 51.0 (0.7) | 45.9 (0.7) | 42.0 (0.7) | 40.5 (0.7) | <0.0001 |
| Triglycerides (mg/dl) | 108.8 (3.5) | 141.3 (4.6) | 172.3 (7.7) | 189.0 (7.0) | <0.0001 |
| Coagulation/inflammation | |||||
| PAI-1 (ng/ml) | 18.6 (1.0) | 22.8 (0.9) | 28.0 (1.0) | 31.7 (1.4) | <0.0001 |
| Fibrinogen (mg/dl) | 273.3 (2.9) | 277.7 (3.0) | 287.3 (2.8) | 291.8 (3.1) | <0.0001 |
| CRP (mg/liter) | 3.1 (0.31) | 3.4 (0.2) | 4.4 (0.3) | 5.5 (0.4) | <0.0001 |
Data are proportions (percentage), means (±se). NS, Nonsignificant.
a
P value for trend across TNF-α categories.