Table 1.
Characteristics of the study population stratified according to kidney function (based on eGFR levels)
| Total group | Quartile 1 (eGFR < 131 ml/min/1.73m2) |
Quartile 2 (eGFR 131–145 ml/min/1.73m2) |
Quartile 3 (eGFR 146–155 ml/min/1.73m2) |
Quartile 4 (eGFR ≥ 156 ml/min/1.73m2) |
||
|---|---|---|---|---|---|---|
| N | 956 | 239 | 239 | 239 | 239 | |
| Age (years) | 24.5 ± 3.12 | 25.5 ± 2.78bc | 25.4 ± 2.99de | 23.6 ± 2.90bd | 23.4 ± 3.17ce | < 0.001 |
| Ethnicity (black, %) | 472 (49.4) | 88 (36.8) | 129 (54.0) | 134 (56.1) | 121 (50.6) | < 0.001 |
| Sex (women, %) | 476 (49.8) | 129 (54.0) | 120 (50.2) | 127 (53.1) | 100 (41.8) | 0.007 |
| Body mass index (kg/m2) | 25.1 ± 5.50 | 25.6 ± 4.88 | 25.6 ± 6.64 | 25.0 ± 6.15 | 24.1 ± 5.19 | 0.055 |
| Waist circumference (cm) | 80.5 ± 12.5 | 81.6 ± 12.1 | 81.6 ± 13.1 | 79.7 ± 13.2 | 79.1 ± 11.1 | 0.291 |
| Waist-to-height ratio | 0.48 ± 0.07 | 0.48 ± 0.07 | 0.49 ± 0.07e | 0.48 ± 0.08 | 0.47 ± 0.06e | 0.512 |
| Blood pressure measurements | ||||||
| 24 h SBP (mmHg) | 117 ± 9.58 | 117 ± 9.88 | 117 ± 9.56 | 116 ± 9.63 | 118 ± 9.28 | 0.648 |
| 24 h DBP (mmHg) | 69 ± 5.96 | 69 ± 6.12 | 69 ± 5.91 | 68 ± 5.91 | 68 ± 5.87 | 0.515 |
| 24 h PP (mmHg) | 49 ± 7.24 | 48 ± 7.60 | 48 ± 6.62 | 48 ± 7.63 | 49 ± 7.05 | 0.264 |
| Office SBP (mmHg) | 123 ± 10.5 | 124 ± 11.4 | 123 ± 11.1 | 122 ± 9.55 | 122 ± 9.58 | 0.181 |
| Office DBP (mmHg) | 73 ± 7.87 | 74 ± 8.49 | 74 ± 7.89 | 74 ± 7.41 | 72 ± 7.65 | 0.653 |
| Office PP (mmHg) | 49 ± 7.82 | 50 ± 8.51 | 49 ± 7.35 | 48 ± 7.54 | 49 ± 7.81 | 0.226 |
| Biochemical markers | ||||||
| Total cholesterol (mmol/l) | 3.46 (1.95; 5.78) | 4.36 (2.87; 6.11)abc | 3.91 (2.65; 5.82)ade | 3.33 (2.11; 5.54)bdf | 2.53 (1.59; 4.02)cef | < 0.001 |
| HDL-C (mmol/l) | 1.04 (0.55; 1.87) | 1.31 (0.80; 2.24)abc | 1.13 (0.65; 1.84) ade | 1.00 (0.54; 1.71)bdf | 0.80 (0.50; 1.41)cef | < 0.001 |
| LDL-C (mmol/l) | 2.19 (1.04; 4.18) | 2.69 (1.46; 4.51)bc | 2.53 (1.45; 4.16)de | 2.18 (1.11; 4.11)bdf | 1.55 (0.82; 2.88)cef | < 0.001 |
| Triglycerides (mmol/l) | 0.70 (0.30; 1.82) | 0.88 (0.46; 1.93)bc | 0.83 (0.35; 2.45)de | 0.66 (0.32; 1.62)bdf | 0.50 (0.26; 1.09)cef | < 0.001 |
| Triglyceride-to-HDL-C ratio | 0.67 (0.28; 2.09) | 0.67 (0.29; 1.90) | 0.73 (0.27; 3.27)e | 0.66 (0.29; 2.09) | 0.63 (0.26; 1.76)e | 0.264 |
| HbA1c (%) | 5.31 ± 0.32 | 5.32 ± 0.27 | 5.36 ± 0.31e | 5.30 ± 0.33 | 5.26 ± 0.33e | 0.198 |
| C-reactive protein (mg/l) | 0.83 (0.07; 9.28) | 0.97 (0.08; 10.9)c | 0.97 (0.13; 8.74)e | 0.98 (0.10; 10.2)f | 0.53 (0.04; 9.31)cef | < 0.001 |
| GGT(U/l) | 17.8 (5.80; 54.7) | 21.3 (9.00; 54.7)bc | 21.8 (7.80; 66.1)de | 17.1 (5.70; 52.4)bdf | 12.5 (4.80; 42.5)cef | < 0.001 |
| Cotinine (ng/ml) | 3.63 (1.00; 327) | 2.74 (1; 291) | 4.40 (1.00; 384) | 3.92 (1.00; 310) | 3.73 (1.00; 339) | 0.676 |
| Creatinine (µmol/l) | 65.5 ± 17.6 | 85.6 ± 14.5 abc | 69.9 ± 9.06 ade | 59.8 ± 8.27 bdf | 46.8 ± 8.85 cef | < 0.001 |
| Kidney function markers | ||||||
| eGFR (ml/min/1.73m2) | 143 ± 21.9 | 113 ± 13.4 abc | 141 ± 1.49 ade | 151 ± 2.92 bdf | 169 ± 9.31 cef | < 0.001 |
| Urinary albumin (mg/L)# | 5.43 (5.21; 5.65) | 5.31 (4.90; 5.75) | 5.30 (4.89; 5.74) | 5.40 (4.98; 5.85) | 5.71 (5.27; 6.18) | 0.706 |
| UMOD (mg/creat) | 40.9 (18.9; 81.3) | 39.3 (15.6; 84.5) | 42.0 (20.0; 86.4) | 38.8 (14.6; 82.1) | 43.5 (23.7; 79.8) | 0.071 |
| CKD273 classifier | -0.55 ± 0.39 | − 0.45 ± 0.36bc | -0.46 ± 0.39de | -0.58 ± 0.40bdf | − 0.72 ± 0.36cef | < 0.001 |
| Lifestyle factors | ||||||
| SES score | 20.5 ± 6.03 | 22.9 ± 5.96abc | 20.8 ± 6.50ad | 19.0 ± 5.40bd | 19.4 ± 5.44c | < 0.001 |
| SR smoking, n (%) | 233 (24.4) | 44 (18.4) | 66 (27.6) | 59 (24.7) | 64 (26.9) | 0.136 |
| SR alcohol use, n (%) | 515 (54.2) | 127 (53.6) | 130 (54.9) | 131 (54.8) | 127 (53.6) | 0.999 |
| TEE (kCal/kg/day) | 32.7 ± 9.18 | 31.1 ± 4.46bc | 33.3 ± 16.9 | 32.9 ± 4.22b | 33.5 ± 4.75c | < 0.001 |
Abbreviations: eGFR, estimated glomerular filtration rate; SBP, systolic blood pressure; DBP, diastolic blood pressure; PP, pulse pressure; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; HbA1c, glycated haemoglobin; GGT, gamma-glutamyl transferase; UMOD, uromodulin; SES, socio-economic status; SR, self-reported; TEE, total energy expenditure.
Notes: values are expressed as arithmetic mean ± standard deviation, geometric mean with 5th and 95th percentiles, or frequency and percentage.
# Urinary albumin ANCOVA (adjusted for urinary creatinine) expressed as least square mean with confidence intervals.
a Statistical significance between quartile 1 and 2; b statistical significance between quartile 1 and 3; c statistical significance between quartile 1 and 4; d statistical significance between quartile 2 and 3; e statistical significance between quartile 2 and 4; f statistical significance between quartile 3 and 4.