Table 1.
Baseline characteristics of study participants according to smoking status
| Variables | All, N=1914 | Never Smoker, n=990 | Former Smoker, n=592 | Current Smoker, n=332 |
|---|---|---|---|---|
| Age, median [IQR], yr | 54 [44−63] | 54 [45−63] | 57 [46−64] | 52 [41−59] |
| Men, n (%) | 1141 (60) | 280 (28) | 554 (94) | 307 (93) |
| Diabetes mellitus, n (%) | 588 (31) | 268 (27) | 201 (34) | 119 (36) |
| Cause of CKD, n (%) | ||||
| Diabetic kidney disease | 435 (23) | 192 (19) | 148 (25) | 95 (29) |
| Hypertensive | 368 (19) | 162 (16) | 141 (24) | 65 (20) |
| GN | 638 (33) | 358 (36) | 186 (31) | 94 (28) |
| Polycystic kidney disease | 340 (18) | 201 (20) | 80 (14) | 59 (18) |
| Interstitial/unspecified | 133 (7) | 77 (8) | 37 (6) | 19 (6) |
| Economic status, n (%) | ||||
| High (>4500 $/mo) | 437 (23) | 212 (21) | 151 (26) | 74 (22) |
| Middle (1500–4500 $/mo) | 1058 (55) | 577 (58) | 311 (53) | 170 (51) |
| Low (<1500 $/mo) | 419 (22) | 201 (20) | 130 (22) | 88 (27) |
| Educational level, n (%) | ||||
| ≤6 yr | 230 (12) | 156 (16) | 51 (9) | 23 (7) |
| 7–12 yr | 900 (47) | 481 (49) | 265 (45) | 154 (47) |
| ≥13 yr | 784 (41) | 353 (36) | 276 (47) | 155 (47) |
| BMI, mean (SD), kg/m2 | 24.5 (3.4) | 24.3 (3.6) | 24.7 (3.0) | 25.0 (3.6) |
| Systolic BP, mean (SD), mm Hg | 128 (16) | 127 (16) | 128 (17) | 130 (17) |
| Medications, n (%) | ||||
| RAAS blocker | 1635 (85) | 828 (84) | 513 (87) | 294 (89) |
| Lipid-lowering agents | 944 (49) | 502 (51) | 275 (47) | 167 (50) |
| Calcium-based phosphate binders | 168 (9) | 113 (11) | 38 (6) | 14 (4) |
| eGFR, median [IQR], ml/min per 1.73 m2 | 48 [29−76] | 48 [30−81] | 45 [27−68] | 50 [30−78] |
| eGFR categories, n (%) | ||||
| ≥90 ml/min per 1.73 m2 | 244 (13) | 151 (15) | 48 (8) | 45 (14) |
| 60–89 ml/min per 1.73 m2 | 371 (19) | 194 (20) | 112 (19) | 65 (20) |
| 30–59 ml/min per 1.73 m2 | 715 (40) | 367 (35) | 255 (39) | 134 (40) |
| 15–29 ml/min per 1.73 m2 | 412 (22) | 211 (21) | 139 (24) | 72 (22) |
| <15 ml/min per 1.73 m2 | 119 (6) | 65 (7) | 38 (6) | 16 (5) |
| UPCR, median [IQR], g/g | 0.52 [0.15–1.54] | 0.48 [0.13–1.25] | 0.60 [0.18–1.68] | 0.56 [0.20–2.05] |
| Hemoglobin, mean (SD), g/dl | 13 (2) | 12 (2) | 13 (2) | 14 (2) |
| Glucose, mean (SD), mg/dl | 110 (39) | 107 (35) | 108 (34) | 120 (53) |
| Albumin, mean (SD), g/dl | 4.2 (0.4) | 4.2 (0.4) | 4.2 (0.4) | 4.2 (0.5) |
| Triglyceride, median [IQR], mg/dl | 132 [91−194] | 123 [88−183] | 129 [87−193] | 157 [113−233] |
| Total cholesterol, mean (SD), mg/dl | 175 (39) | 179 (38) | 169 (36) | 176 (42) |
| LDL cholesterol, mean (SD), mg/dl | 98 (32) | 100 (32) | 95 (30) | 99 (35) |
| HDL cholesterol, mean (SD), mg/dl | 50 (16) | 53 (16) | 47 (14) | 46 (15) |
| Calcium-phosphate products, mean (SD), mg2/dl2 | 34 (6) | 35 (6) | 33 (6) | 32 (6) |
| Intact PTH, median [IQR], pg/ml | 51 [33−83] | 52 [33−81] | 53 [34−87] | 47 [31−79] |
IQR, interquartile range; BMI, body mass index; RAAS, renin-angiotensin-aldosterone system; UPCR, urinary protein-to-creatinine ratio; PTH, parathyroid hormone.