Table 1 Characteristics of study participants in the National Health and Nutrition Examination Survey with complete data, randomly split into testing and training sets
From: Use of biomarkers of metals to improve prediction performance of cardiovascular disease mortality
Characteristic | Training data (n = 3,542) | Testing data (n = 3,543) |
|---|---|---|
Follow-up characteristics | ||
CVD mortality, number of cases (%) | 211 (6%) | 209 (5.9%) |
Follow-up time, mean (SD), years | 8.9 (4.0) | 8.7 (4.0) |
Baseline characteristics | ||
Age, mean (SD), years | 60 (12) | 60 (13) |
Race/ethnicity, number of participants (%) | ||
Non-Hispanic White | 1,689 (48%) | 1,667 (47%) |
Non-Hispanic Black | 713 (20%) | 720 (20%) |
Hispanic | 850 (24%) | 886 (25%) |
Other race | 290 (8.2%) | 270 (7.6%) |
Male, number of participants (%) | 1,795 (51%) | 1,748 (49%) |
Current smoker, number of participants (%) | 644 (18%) | 659 (19%) |
Systolic blood pressure, mean (SD), mmHg | 129 (20) | 129 (19) |
Total serum cholesterol, mean (SD), mg/dL | 199 (42) | 200 (43) |
HDL cholesterol, mean (SD), mg/dL | 54 (17) | 54 (17) |
BMI categories, number of participants (%) | ||
Under- and normal weight (< 25 kg/m2) | 921 (26%) | 918 (26%) |
Overweight (25–30 kg/m2) | 1,294 (37%) | 1,231 (35%) |
Obese (≥ 30 kg/m2) | 1,327 (37%) | 1,394 (39%) |
Hypertension, number of participants (%) | 1,688 (48%) | 1,721 (49%) |
Diabetes, number of participants (%) | 675 (19%) | 641 (19%) |
Blood lead, median (IQR), µg/dL | 1.41 (0.93, 2.19) | 1.41 (0.92, 2.23) |
Blood mercury, median (IQR), µg/L | 0.89 (0.46, 1.80) | 0.88 (0.47, 1.72) |
Blood cadmium, median (IQR), µg/L | 0.35 (0.22, 0.62) | 0.35 (0.21, 0.60) |
Urinary total arsenic, median (IQR), µg/L | 8.06 (3.89, 16.00) | 7.64 (3.88, 17.03) |
Urinary dimethylarsinic acid, median (IQR), µg/L | 3.61 (2.00, 6.12) | 3.56 (2.01, 6.29) |
Urinary arsenobetaine, median (IQR), µg/L | 1.30 (0.80, 6.36) | 1.30 (0.82, 6.16) |
Urinary cesium, median (IQR), µg/L | 4.46 (2.74, 6.62) | 4.53 (2.80, 6.86) |
Urinary molybdenum, median (IQR), µg/L | 40.20 (21.60, 68.66) | 40.70 (21.60, 69.60) |
Urinary thallium, median (IQR), µg/L | 0.15 (0.09, 0.23) | 0.15 (0.09, 0.24) |
Urinary cobalt, median (IQR), µg/L | 0.34 (0.21, 0.54) | 0.35 (0.21, 0.56) |
Urinary barium, median (IQR), µg/L | 1.12 (0.56, 2.16) | 1.17 (0.57, 2.24) |
Urinary lead, median (IQR), µg/L | 0.52 (0.28, 0.92) | 0.54 (0.30, 0.94) |
Urinary cadmium, median (IQR), µg/L | 0.28 (0.14, 0.54) | 0.29 (0.14, 0.57) |
Urinary mercury, median (IQR), µg/L | 0.34 (0.15, 0.76) | 0.34 (0.15, 0.76) |
Urinary uranium, median (IQR), µg/L | 0.01 (0.00, 0.01) | 0.01 (0.00, 0.01) |
Urinary tungsten, median (IQR), µg/L | 0.06 (0.03, 0.12) | 0.07 (0.03, 0.13) |
Urinary antimony, median (IQR), µg/L | 0.05 (0.03, 0.09) | 0.05 (0.03, 0.09) |
Urinary creatinine, median (IQR), mg/dL | 100.00 (58.00, 153.75) | 105.00 (60.00, 155.00) |