Table 1.
Baseline characteristics of 13,328 NHANES III participants by serum 25(OH)D level
| Characteristic | 25(OH)D Levels (ng/ml) |
|||
|---|---|---|---|---|
| Total(n = 13,328) | ≥15(n = 11,238) | <15(n = 2090) | P | |
| Age (yr; mean [SE]) | 44.3 (0.5) | 44.3 (0.5) | 44.8 (0.6) | 0.42 |
| Female gender (% [SE]) | 52.1 (0.5) | 50.4 (0.5) | 69.5 (1.5) | <0.001 |
| Race/ethnicity (% [SE]) | ||||
| non-Hispanic white | 77.8 (1.2) | 81.2 (1.1) | 42.3 (2.7) | <0.001 |
| non-Hispanic black | 10.0 (0.6) | 7.3 (0.5) | 38.8 (2.2) | <0.001 |
| Mexican American | 4.8 (0.4) | 4.5 (0.4) | 7.2 (0.8) | <0.001 |
| other | 7.4 (0.8) | 7.0 (0.9) | 11.6 (1.8) | 0.004 |
| Diabetes (% [SE]) | 6.6 (0.3) | 6.3 (0.3) | 9.0 (1.0) | 0.003 |
| Hypertension (% [SE]) | 23.7 (0.8) | 23.4 (0.9) | 26.9 (1.5) | 0.02 |
| Smoking (% [SE]) | ||||
| former | 26.2 (0.6) | 26.7 (0.7) | 20.9 (1.5) | 0.001 |
| current | 28.3 (0.8) | 27.9 (0.9) | 32.3 (2.3) | 0.06 |
| History of CVD (% [SE]) | 7.6 (0.4) | 7.6 (0.5) | 7.6 (0.9) | 0.99 |
| Low SES (% [SE]) | 32.8 (1.2) | 32.0 (1.3) | 41.0 (1.8) | <0.001 |
| Season (% [SE]) | ||||
| Winter (January through March) | 16.4 (2.9) | 15.1 (2.6) | 30.3 (5.6) | <0.001 |
| Spring (April through June) | 25.9 (4.1) | 26.1 (4.2) | 23.8 (4.2) | 0.39 |
| Summer (July through September) | 33.3 (4.9) | 34.7 (5.1) | 18.8 (3.7) | <0.001 |
| Fall (October through December) | 24.3 (4.2) | 24.1 (4.3) | 27.0 (4.4) | 0.36 |
| Use of vitamin D supplementation (% [SE]) | 28.9 (0.7) | 30.3 (0.7) | 13.9 (1.5) | <0.001 |
| Physical activity level (% [SE]) | ||||
| moderate | 54.3 (0.9) | 55.0 (1.0) | 46.9 (1.7) | <0.001 |
| high | 21.4 (0.9) | 22.5 (0.9) | 10.8 (1.1) | <0.001 |
| BMI (kg/m2; mean [SE]) | 26.5 (0.1) | 26.4 (0.1) | 28.2 (0.3) | <0.001 |
| Albumin excretion ≥30 mg/g of creatinine (% [SE]) | 8.2 (0.4) | 7.9 (0.4) | 12.1 (1.2) | <0.001 |
| Use of cholesterol lowering medication (% [SE]) | 2.9 (0.2) | 2.8 (0.2) | 3.9 (1.0) | 0.14 |
| HDL cholesterol (mg/dl; mean [SE]) | 50.8 (0.3) | 50.6 (0.4) | 52.3 (0.6) | 0.002 |
| Total cholesterol (mg/dl; mean [SE]) | 203.7 (0.8) | 203.8 (0.9) | 202.2 (1.7) | 0.38 |
| Serum phosphate (mg/dl; mean [SE]) | 3.45 (0.01) | 3.44 (0.01) | 3.49 (0.02) | 0.005 |
| Serum hemoglobin (g/dl; mean [SE]) | 14.00 (0.03) | 14.20 (0.03) | 13.50 (0.05) | <0.001 |
| Serum albumin (g/dl; mean [SE]) | 4.18 (0.02) | 4.20 (0.02) | 4.05 (0.02) | <0.001 |
| C-reactive protein >0.021 (mg/L; % [SE]) | 28.1 (1.2) | 27.3 (1.3) | 37.2 (2.0) | <0.001 |
| eGFR <60 ml/min per 1.73 m2 (% [SE]) | 4 (0.3) | 4.0 (0.3) | 4.5 (0.7) | 0.48 |
CVD, cardiovascular disease.