Table 3.
Baseline characteristics of NHANES participants between 2007 and 2018 after PSM.
| Characteristic | Total | None-stone formers | Stone formers | P -value |
|---|---|---|---|---|
| No. (%) | No. (%) | No. (%) | ||
| Total patients | 5,488 | 2,744 (50.0) | 2,744 (50.0) | |
| Gender | 0.786 | |||
| Male | 3,056 (55.7) | 1,523 (55.5) | 1,533 (55.9) | |
| Female | 2,432 (44.3) | 1,221 (44.5) | 1,211 (44.1) | |
| Age | 0.459 | |||
| <50 years | 1,876 (34.2) | 925 (33.7) | 951 (34.7) | |
| ≥50 years | 3,612 (65.8) | 1,819 (66.3) | 1,793 (65.3) | |
| Race | 0.783 | |||
| Non-Hispanic white | 3,059 (55.7) | 1,542 (56.2) | 1,517 (55.3) | |
| Non-Hispanic black | 711 (13.0) | 359 (13.1) | 352 (12.8) | |
| Mexican American | 697 (12.7) | 343 (12.5) | 354 (12.9) | |
| Other Hispanic | 610 (11.1) | 306 (11.2) | 304 (11.1) | |
| Other | 411 (7.5) | 194 (7.1) | 217 (7.9) | |
| Education level | 0.991 | |||
| Less than high school | 1,363 (24.8) | 683 (24.9) | 680 (24.8) | |
| High school or equivalent | 1,240 (22.6) | 621 (22.6) | 619 (22.6) | |
| College or above | 2,885 (52.6) | 1,440 (52.5) | 1,445 (52.7) | |
| Marital status | 0.155 | |||
| Married | 3,200 (58.3) | 1,626 (59.3) | 1,574 (57.4) | |
| Unmarried | 2,288 (41.7) | 1,118 (40.7) | 1,170 (42.6) | |
| Family income | 0.786 | |||
| < $20,000 | 1,324 (24.1) | 668 (24.3) | 656 (23.9) | |
| ≥$20,000 | 3,945 (71.9) | 1,971 (71.8) | 1,974 (71.9) | |
| Unknown | 219 (4.0) | 105 (3.8) | 114 (4.2) | |
| BMI (kg/m2) | 0.891 | |||
| <25.0 | 1,062 (19.4) | 533 (19.4) | 529 (19.3) | |
| ≥25.0 | 4,426 (80.6) | 2,211 (80.6) | 2,215 (80.7) | |
| Hypertension | 0.666 | |||
| Yes | 2,768 (50.4) | 1,376 (50.1) | 1,392 (50.7) | |
| No | 2,720 (49.6) | 1,368 (49.9) | 1,352 (49.3) | |
| Diabetes mellitus | 0.096 | |||
| Yes | 1,219 (22.2) | 603 (22.0) | 616 (22.4) | |
| No | 4,107 (74.8) | 2,073 (75.5) | 2,034 (74.1) | |
| Borderline | 162 (3.0) | 68 (2.5) | 94 (3.4) | |
| Smoking status | 0.084 | |||
| Never | 2,684 (48.9) | 1,339 (48.8) | 1,345 (49.0) | |
| Former | 1,703 (31.0) | 882 (32.1) | 821 (29.9) | |
| Current | 1,101 (20.1) | 523 (19.1) | 578 (21.1) | |
| Drinking | 0.768 | |||
| Yes | 3,856 (70.3) | 1,933 (70.4) | 1,923 (70.1) | |
| No/Unknown | 1,632 (29.7) | 811 (29.6) | 821 (29.9) | |
| Vigorous recreational activities | 0.519 | |||
| Yes | 815 (14.9) | 399 (14.5) | 416 (15.2) | |
| No | 4,673 (85.1) | 2,345 (85.5) | 2,328 (84.8) | |
| Moderate recreational activities | 0.693 | |||
| Yes | 1,954 (35.6) | 970 (35.3) | 984 (35.9) | |
| No | 3,534 (64.4) | 1,774 (64.7) | 1,760 (64.1) | |
| Blood urea nitrogen (mg/dL) | 15.02, 6.96 | 14.74, 6.63 | 15.29, 7.27 | 0.003 |
| Creatinine (mg/dL) | 0.96, 0.60 | 0.95, 0.45 | 0.98, 0.72 | 0.057 |
| Uric acid (mg/dL) | 5.69, 1.50 | 5.73, 1.48 | 5.65, 1.52 | 0.042 |
| eGFR [mL/(min·1.73 m2)] | 75.36, 25.24 | 75.68, 24.85 | 75.05, 25.61 | 0.352 |
| Daily intake (M, SD) | ||||
| Protein (mg) | 79.46, 40.56 | 80.38, 41.18 | 78.53, 39.92 | 0.129 |
| Moisture (g) | 2.88, 1.48 | 2.88, 1.47 | 2.88, 1.50 | 0.959 |
| Phosphorus (mg) | 1,304.9, 642.0 | 1,301.9, 642.3 | 1,307.9, 641.9 | 0.727 |
| Magnesium (mg) | 285.38, 138.83 | 287.90, 138.12 | 282.86, 139.52 | 0.178 |
| Iron (mg) | 14.50, 8.26 | 14.58, 8.20 | 14.41, 8.33 | 0.461 |
| Zinc (mg) | 11.08, 6.68 | 11.30, 6.93 | 10.87, 6.43 | 0.018 |
| Copper (mg) | 1.23, 0.72 | 1.27, 0.75 | 1.20, 0.69 | <0.001 |
| Selenium (mcg) | 109.18, 61.61 | 108.30, 60.76 | 110.06, 62.44 | 0.290 |
For categorical variables, P-values were analyzed by chi-square tests. For continuous variables, the t-test for slope was used in generalized linear models.
NHANES, National Health and Nutrition Examination Survey; BMI, body mass index; eGFR, estimated glomerular filtration rate; SD, standard deviation; PSM, propensity score matching.