TABLE 1.
Baseline characteristics of national health and nutrition examination survey (NHANES) participants between 2001 and 2004 before propensity score matching (PSM).
| Characteristic | Non-ED | ED | p |
| Total patients | 2,649 | 1,096 | |
| Age (years), n (%) | < 0.001 | ||
| < 40 years | 1130 (30.2%) | 73 (1.9%) | |
| ≥ 40 years | 1519 (40.6%) | 1023 (27.3%) | |
| Race, n (%) | < 0.001 | ||
| Mexican American | 512 (13.7%) | 202 (5.4%) | |
| Other hispanic | 85 (2.3%) | 38 (1%) | |
| Non-hispanic white | 1428 (38.1%) | 674 (18%) | |
| Non-hispanic black | 531 (14.2%) | 160 (4.3%) | |
| Other race–including multi-racial | 93 (2.5%) | 22 (0.6%) | |
| Education level, n (%) | < 0.001 | ||
| Less than high school | 592 (15.8%) | 431 (11.5%) | |
| High school diploma | 692 (18.5%) | 220 (5.9%) | |
| More than high school | 1365 (36.4%) | 445 (11.9%) | |
| Marital status, n (%) | < 0.001 | ||
| Married | 1580 (42.2%) | 784 (20.9%) | |
| Unmarried | 1069 (28.5%) | 312 (8.3%) | |
| Annual household income, n (%) | < 0.001 | ||
| Over $20,000 | 2190 (58.5%) | 788 (21%) | |
| Under $20,000 | 459 (12.3%) | 308 (8.2%) | |
| BMI (kg/m2), n (%) | 0.010 | ||
| < 25.0 | 805 (21.5%) | 286 (7.6%) | |
| ≥ 25.0 | 1844 (49.2%) | 810 (21.6%) | |
| Hypertension, n (%) | < 0.001 | ||
| Yes | 631 (16.8%) | 584 (15.6%) | |
| No | 2018 (53.9%) | 512 (13.7%) | |
| Current health status, n (%) | < 0.001 | ||
| Excellent, very good, good | 2264 (60.5%) | 733 (19.6%) | |
| Fair or poor | 385 (10.3%) | 363 (9.7%) | |
| Diabetes, n (%) | < 0.001 | ||
| Yes | 134 (3.6%) | 256 (6.8%) | |
| No | 2485 (66.4%) | 822 (21.9%) | |
| Borderline | 30 (0.8%) | 18 (0.5%) | |
| Magnesium (mg), median (IQR) | 301 (217, 407) | 256.5 (185.75, 335) | < 0.001 |
| Zinc (mg), median (IQR) | 12.76 (8.49, 18.04) | 10.1 (6.93, 14.64) | < 0.001 |
| Copper (mg), median (IQR) | 1.34 (0.94, 1.83) | 1.1 (0.82, 1.5) | < 0.001 |
| Selenium (mcg), median (IQR) | 117.3 (85.1, 160.7) | 97.4 (71.57, 130.83) | < 0.001 |
For categorical variables, P values were analyzed by chi-square tests. For continuous variables, P values were analyzed by Wilcoxon rank sum test. BMI, body mass index; PSM, propensity score matching; IQR, interquartile range.