Table 1.
Characteristics of study participants
| Characteristic | Quartiles of fluid intake (L/day) |
|||||
|---|---|---|---|---|---|---|
| Q1 (<2.147) | Q2 (2.147 to 2.789) | Q3 (2.789 to 3.576) | Q4 (≥3.576) | Total | p Value | |
| N=545 | N=546 | N=546 | N=545 | N=2182 | ||
| Continuous variables | ||||||
| Age, mean (SD) | 68.81 (10.50) | 67.45 (10.36) | 66.15 (9.97) | 63.98 (9.51) | 66.60 (10.24) | <0.001 |
| BMI, mean (SD) | 26.36 (4.829) | 27.00 (4.800) | 27.41 (5.237) | 27.82 (5.341) | 27.15 (5.083) | <0.001 |
| Waist circumference (cm) | 94.28 (12.19) | 96.91 (11.88) | 98.05 (12.70) | 99.68 (13.13) | 97.23 (12.63) | <0.001 |
| Systolic blood pressure (mm HG) | 139.55 (22.53) | 138.45 (22.86) | 136.60 (22.12) | 136.03 (20.89) | 137.66 (22.14) | 0.037 |
| eGFR | 60.82 (13.53) | 62.22 (13.80) | 62.83 (12.55) | 64.18 (13.41) | 62.51 (13.38) | <0.001 |
| WCC (1000 cells/mL) | 6.99 (2.31) | 6.87 (2.81) | 7.14 (2.49) | 7.15 (2.03) | 7.04 (2.26) | 0.134 |
| Haemoglobin (g/dL), mean (SD) | 13.62 (1.31) | 13.87 (1.33) | 13.98 (1.34) | 14.20 (1.31) | 13.92 (1.34) | <0.001 |
| Serum cholesterol (mg/dL) | 229.28 (47.48) | 223.58 (43.34) | 222.36 (43.19) | 223.64 (41.36) | 224.71 (43.95) | 0.043 |
| Serum HDL cholesterol (mg/dL) | 53.68 (15.47) | 51.60 (16.09) | 51.10 (15.57) | 51.30 (16.30) | 51.92 (15.88) | 0.027 |
| Serum triglycerides (mg/dL) | 154.64 (96.54) | 157.68 (103.98) | 160.93 (113.19) | 161.95 (112.64) | 158.80 (106.78) | 0.666 |
| Serum apolipoprotein AI (mg/dL) | 152.33 (26.56) | 146.84 (26.43) | 146.69 (26.06) | 146.64 (26.81) | 148.12 (26.56) | <0.001 |
| Plasma fibrinogen (mg/dL) | 318.11 (96.84) | 322.13 (101.86) | 323.74 (90.67) | 324.53 (95.34) | 322.14 (96.22) | 0.710 |
| Serum C reactive protein (mg/dL) | 0.51 (0.71) | 0.50 (0.88) | 0.46 (0.60) | 0.51 (0.75) | 0.49 (0.74) | 0.671 |
| Serum sodium (mmol/L) | 141.93 (2.53) | 141.80 (2.80) | 141.79 (2.38) | 141.51 (2.92) | 141.76 (2.67) | 0.061 |
| Serum potassium (mmol/L) | 4.03 (0.32) | 4.06 (0.35) | 4.04 (0.36) | 4.05 (0.36) | 4.04 (0.35) | 0.694 |
| Serum total calcium (mmol/L) | 9.34 (0.44) | 9.37 (0.45) | 9.36 (0.42) | 9.36 (0.44) | 9.36 (0.44) | 0.863 |
| Serum phosphorus (mmol/L) | 3.47 (0.50) | 3.42 (0.51) | 3.43 (0.49) | 3.43 (0.50) | 3.44 (0.50) | 0.413 |
| Serum glucose (mg/dL) | 101.84 (35.44) | 105.17 (39.34) | 102.42 (32.63) | 111.98 (55.94) | 105.35 (41.98) | <0.001 |
| Serum blood urea nitrogen (mg/dL) | 17.36 (6.14) | 17.08 (5.84) | 16.96 (6.44) | 16.59 (6.66) | 17.00 (6.28) | 0.238 |
| Serum creatinine (mg/dL) | 1.14 (0.55) | 1.14 (0.28) | 1.15 (0.35) | 1.15 (0.31) | 1.14 (0.39) | 0.964 |
| Serum albumin (g/dL) | 4.14 (0.34) | 4.16 (0.32) | 4.17 (0.32) | 4.17 (0.35) | 4.16 (0.33) | 0.214 |
| Urinary albumin (µg/mL) | 43.34 (271.38) | 31.73 (133.15) | 40.95 (196.61) | 64.02 (437.72) | 44.99 (283.29) | 0.299 |
| HOMA-IR | 3.48 (6.93) | 3.19 (3.97) | 3.75 (6.39) | 4.56 (14.94) | 3.75 (9.06) | 0.075 |
| Urine albumin to creatinine ratio (mg/g), mean (SD) | 0.57 (4.27) | 0.33 (2.07) | 0.39 (1.55) | 0.60 (3.83) | 0.47 (3.14) | 0.430 |
| Categorical variables | ||||||
| Male, n (%) | 196 (36.0) | 271 (49.6) | 300 (54.9) | 330 (60.6) | 1097 (50.3) | 0.004 |
| Non-Hispanic white, n (%) | 310 (56.9) | 331 (60.6) | 346 (63.4) | 360 (66.1) | 1347 (61.7) | 0.050 |
| Ever smoker, n (%) | 277 (50.8) | 303 (55.5) | 314 (57.5) | 348 (63.9) | 1242 (56.9) | 0.001 |
| Diabetes mellitus, n (%) | 57 (10.5) | 67 (12.3) | 64 (11.7) | 68 (12.5) | 256 (11.7) | 0.638 |
| Cancer, n (%) | 81 (14.9) | 96 (17.6) | 105 (19.3) | 89 (16.4) | 371 (17.0) | 0.519 |
| Emphysema, n (%) | 24 (4.4) | 13 (2.4) | 27 (4.9) | 20 (3.7) | 84 (3.8) | 0.201 |
| Arthritis, n (%) | 238 (43.7) | 209 (38.3) | 205 (37.5) | 209 (38.3) | 861 (39.5) | 0.207 |
BMI, body mass index; eGFR, estimated glomerular filtration rate; HDL, high-density lopoprotein; WCC, white cell count.