Table 1.
Baseline characteristics of the study participants
| Variables | Total (n = 3,537) | Klotho levels quartiles (pg/mL) | p value | ||||
|---|---|---|---|---|---|---|---|
| Q1 (n = 708) | Q2 (n = 705) | Q3 (n = 709) | Q4 (n = 707) | Q5 (n = 708) | |||
| Age, years | 61.4±10.1 | 62.8±10.2 | 62.2±10.0 | 61.7±10.1 | 60.6±9.8 | 59.5±10.0 | <0.001 |
| Sex, n (%) | 0.693 | ||||||
| Male | 1,814 (51.3) | 366 (51.7) | 375 (53.2) | 367 (51.8) | 353 (49.9) | 353 (49.9) | |
| Female | 1,723 (48.7) | 342 (48.3) | 330 (46.8) | 342 (48.2) | 354 (50.1) | 355 (50.1) | |
| Race and ethnicity, n (%) | <0.001 | ||||||
| Mexican American | 715 (20.2) | 137 (19.4) | 144 (20.4) | 131 (18.5) | 159 (22.5) | 144 (20.3) | |
| Other Hispanic | 458 (12.9) | 77 (10.9) | 73 (10.4) | 103 (14.5) | 95 (13.4) | 110 (15.5) | |
| Non-Hispanic white | 1,199 (33.9) | 246 (34.7) | 286 (40.6) | 247 (34.8) | 234 (33.1) | 186 (26.3) | |
| Non-Hispanic black | 835 (23.6) | 182 (25.7) | 137 (19.4) | 157 (22.1) | 149 (21.1) | 210 (29.7) | |
| Other race | 330 (9.3) | 66 (9.3) | 65 (9.2) | 71 (10.0) | 70 (9.9) | 58 (8.2) | |
| Educational level, n (%) | 0.642 | ||||||
| High school or less | 2,096 (59.3) | 435 (61.6) | 426 (60.4) | 409 (57.9) | 420 (59.4) | 406 (57.3) | |
| Some college | 901 (25.5) | 164 (23.2) | 179 (25.4) | 183 (25.9) | 189 (26.7) | 186 (26.3) | |
| College or above | 536 (15.2) | 107 (15.2) | 100 (14.2) | 115 (16.3) | 98 (13.9) | 116 (16.4) | |
| Marital status, n (%) | 0.449 | ||||||
| Married | 2,044 (57.8) | 389 (54.9) | 434 (61.6) | 413 (58.3) | 412 (58.3) | 396 (55.9) | |
| Never married | 303 (8.6) | 57 (8.1) | 56 (8.0) | 57 (8.1) | 61 (8.6) | 72 (10.2) | |
| Living with a partner | 137 (3.9) | 31 (4.4) | 27 (3.8) | 23 (3.2) | 27 (3.8) | 29 (4.1) | |
| Other | 1,051 (29.7) | 231 (32.6) | 187 (26.6) | 215 (30.4) | 207 (29.3) | 211 (29.8) | |
| Physical activity, n (%) | 0.130 | ||||||
| Sedentary | 2,362 (66.8) | 494 (69.8) | 460 (65.2) | 466 (65.8) | 460 (65.1) | 482 (68.1) | |
| Moderate | 918 (26.0) | 167 (23.6) | 192 (27.2) | 203 (28.7) | 186 (26.3) | 170 (24.0) | |
| Vigorous | 256 (7.2) | 47 (6.6) | 53 (7.5) | 39 (5.5) | 61 (8.6) | 56 (7.9) | |
| HbA1c, n (%) | <0.001 | ||||||
| <7.0 | 2,025 (57.4) | 499 (65.8) | 401 (59.4) | 362 (56.7) | 387 (55.8) | 376 (49.3) | |
| ≥7.0 | 1,502 (42.6) | 259 (34.2) | 274 (40.6) | 277 (43.3) | 306 (44.2) | 386 (50.7) | |
| BMI, n (%) | 0.495 | ||||||
| <25.0 kg/m2 | 425 (12.3) | 95 (12.9) | 75 (11.4) | 78 (12.5) | 74 (10.8) | 103 (13.6) | |
| ≥25.0 kg/m2 | 3,037 (87.7) | 644 (87.1) | 582 (88.6) | 548 (87.5) | 611 (89.2) | 652 (86.4) | |
| Smoking status, n (%) | 0.008 | ||||||
| Never | 1,708 (48.3) | 320 (45.3) | 307 (43.5) | 350 (49.4) | 372 (52.7) | 359 (50.7) | |
| Former | 1,218 (34.5) | 255 (36.1) | 280 (39.7) | 233 (32.9) | 226 (32.0) | 224 (31.6) | |
| Current | 608 (17.2) | 131 (18.6) | 118 (16.7) | 126 (17.8) | 108 (15.3) | 125 (17.7) | |
| Alcohol drinker, n (%) | 2,146 (64.7) | 466 (69.8) | 437 (65.7) | 408 (61.4) | 421 (63.6) | 414 (62.8) | 0.016 |
| Hypertension, n (%) | 2,592 (73.3) | 579 (76.2) | 509 (75.1) | 468 (73.1) | 498 (71.7) | 538 (70.4) | 0.074 |
| CKD, n (%) | 614 (17.4) | 202 (28.6) | 146 (20.7) | 109 (15.4) | 75 (10.6) | 82 (11.6) | <0.001 |
| KS, n (%) | 543 (15.4) | 127 (17.9) | 96 (13.6) | 124 (17.5) | 100 (14.1) | 96 (13.6) | 0.035 |
| Uric acid, μmol/L | 343.9±93.3 | 364.2±103.2 | 354.1±91.6 | 343.9±92.1 | 334.7±83.1 | 322.6±90.1 | <0.001 |
| Albumin, g/dL | 4.2±0.3 | 4.1±0.4 | 4.2±0.3 | 4.2±0.3 | 4.2±0.3 | 4.1±0.4 | 0.005 |
| HDL, mg/dL | 48.2±15.2 | 49.3±16.9 | 47.2±13.9 | 48.7±15.8 | 47.6±13.4 | 48.3±15.6 | 0.064 |
| Total cholesterol, mg/dL | 187.3±46.9 | 183.0±48.4 | 184.2±44.8 | 186.6±45.1 | 188.3±42.3 | 194.2±52.3 | <0.001 |
| Calcium, mg/dL | 9.4±0.4 | 9.4±0.4 | 9.4±0.4 | 9.4±0.4 | 9.4±0.4 | 9.5±0.4 | 0.206 |
| Phosphorus, mg/dL | 3.7±0.6 | 3.8±0.7 | 3.7±0.6 | 3.7±0.6 | 3.7±0.5 | 3.7±0.6 | 0.008 |
| Vitamin D, nmol/La | 55.0 (37.6, 73.0) | 57.2 (37.4, 77.2) | 58.6 (41.1, 76.5) | 53.6 (38.0, 70.8) | 52.9 (37.2, 71.1) | 51.9 (35.8, 68.1) | <0.001 |
| BUN, mg/dLa | 14.0 (11.0, 18.0) | 16.0 (12.0, 21.0) | 15.0 (12.0, 19.0) | 14.0 (11.0, 19.0) | 13.5 (11.0, 17.0) | 13.0 (10.0, 16.0) | <0.001 |
| Triglycerides, mg/dLa | 155.0 (104.0, 236.0) | 153.0 (104.8, 225.2) | 155.0 (107.8, 237.0) | 152.0 (102.0, 233.0) | 155.5 (109.0, 239.8) | 159.0 (99.0, 246.5) | 0.638 |
CKD, chronic kidney disease; BMI, body mass index; HDL, high-density lipoprotein; HbA1c, hemoglobin A1c; BUN, blood urea nitrogen.
aVitamin D, BUN, and triglycerides expressed as median (IQR) and rest are expressed as mean ± SD.