Table 1.
Baseline characteristics of NHANES participants between 2007 and 2018.
| Characteristic | Total | None-stone formers | Stone formers | P -value |
|---|---|---|---|---|
| No. (%) | No. (%) | No. (%) | ||
| Total patients | 28,623 | 25,878 (90.4) | 2,745 (9.6) | |
| Gender | <0.001 | |||
| Male | 13,924 (48.6) | 12,390 (47.9) | 1,534 (55.9) | |
| Female | 14,699 (51.4) | 13,488 (52.1) | 1,211 (44.1) | |
| Age | <0.001 | |||
| <50 years | 14,402 (50.3) | 13,451 (52.0) | 951 (34.6) | |
| ≥50 years | 14,221 (49.7) | 12,427 (48.0) | 1,794 (65.4) | |
| Race | <0.001 | |||
| Non-Hispanic white | 12,098 (42.3) | 10,580 (40.9) | 1,518 (55.3) | |
| Non-Hispanic black | 5,891 (20.6) | 5,539 (21.4) | 352 (12.8) | |
| Mexican American | 4,381 (15.3) | 4,027 (15.6) | 354 (12.9) | |
| Other Hispanic | 3,005 (10.5) | 2,701 (10.4) | 304 (11.1) | |
| Other | 3,248 (11.3) | 3,031 (11.7) | 217 (7.9) | |
| Education level | 0.550 | |||
| Less than high school | 6,859 (24.0) | 6,178 (23.9) | 681 (24.8) | |
| High school or equivalent | 6,541 (22.9) | 5,922 (22.9) | 619 (22.6) | |
| College or above | 15,223 (53.2) | 13,778 (53.2) | 1,445 (52.6) | |
| Marital status | <0.001 | |||
| Married | 14,740 (51.5) | 13,166 (50.9) | 1,574 (57.3) | |
| Unmarried | 13,883 (48.5) | 12,712 (49.1) | 1,171 (42.7) | |
| Family income | 0.198 | |||
| < $20,000 | 6,572 (23.0) | 5,922 (22.9) | 650 (23.7) | |
| ≥$20,000 | 20,647 (72.1) | 18,669 (72.1) | 1,978 (72.1) | |
| Unknown | 1,404 (4.9) | 1,287 (5.0) | 117 (4.3) | |
| BMI (kg/m2) | <0.001 | |||
| <25.0 | 8,048 (28.1) | 7,519 (29.1) | 529 (19.3) | |
| ≥25.0 | 20,575 (71.9) | 18,359 (70.9) | 2,216 (80.7) | |
| Hypertension | <0.001 | |||
| Yes | 10,336 (36.1) | 8,943 (34.6) | 1,393 (50.7) | |
| No | 18,287 (63.9) | 16,935 (65.4) | 1,352 (49.3) | |
| Diabetes mellitus | <0.001 | |||
| Yes | 3,716 (13.0) | 3,099 (12.0) | 617 (22.5) | |
| No | 24,236 (84.7) | 22,202 (85.8) | 2,034 (74.1) | |
| Borderline | 671 (2.3) | 577 (2.2) | 94 (3.4) | |
| Smoking status | <0.001 | |||
| Never | 15,951 (55.7) | 14,608 (56.4) | 1,343 (48.9) | |
| Former | 6,900 (24.1) | 6,045 (23.4) | 855 (31.1) | |
| Current | 5,772 (20.2) | 5,225 (20.2) | 547 (19.9) | |
| Drinking | 0.216 | |||
| Yes | 20,334 (71.0) | 18,356 (70.9) | 1,978 (72.1) | |
| No/Unknown | 8,299 (29.0) | 7,522 (29.1) | 767 (27.9) | |
| Vigorous recreational activities | <0.001 | |||
| Yes | 6,306 (22.0) | 5,890 (22.8) | 416 (15.2) | |
| No | 22,317 (78.0) | 19,988 (77.2) | 2,329 (84.8) | |
| Moderate recreational activities | <0.001 | |||
| Yes | 11,574 (40.4) | 10,590 (40.9) | 984 (35.8) | |
| No | 17,049 (59.6) | 15,288 (59.1) | 1,761 (64.2) | |
| Blood urea nitrogen (mg/dL) | 13.76, 5.99 | 13.60, 5.81 | 15.29, 7.27 | <0.001 |
| Creatinine (mg/dL) | 0.90, 0.45 | 0.89, 0.41 | 0.98, 0.72 | <0.001 |
| Uric acid (mg/dL) | 5.45, 1.45 | 5.43, 1.44 | 5.65, 1.52 | <0.001 |
| eGFR [mL/(min·1.73 m2)] | 83.71, 25.80 | 84.63, 25.65 | 75.04, 25.61 | <0.001 |
| Daily intake (M, SD) | ||||
| Protein (mg) | 80.75, 42.16 | 81.01, 42.33 | 78.38, 40.49 | 0.002 |
| Moisture (g) | 2.88, 1.50 | 2.89, 1.50 | 2.83, 1.47 | 0.062 |
| Phosphorus (mg) | 1,340.9, 667.7 | 1,344.4, 670.2 | 1,307.5, 642.2 | 0.006 |
| Magnesium (mg) | 294.63, 146.58 | 295.88, 147.25 | 282.78, 139.54 | <0.001 |
| Iron (mg) | 14.42, 8.33 | 14.42, 8.33 | 14.41, 8.33 | 0.966 |
| Zinc (mg) | 11.04, 6.71 | 11.06, 6.74 | 10.87, 6.43 | 0.157 |
| Copper (mg) | 1.23, 0.74 | 1.24, 0.74 | 1.20, 0.69 | 0.007 |
| Selenium (mcg) | 112.36, 63.40 | 112.61, 63.50 | 110.03, 62.45 | 0.043 |
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.