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Table 1 Basal and dietary characteristics according to quartiles of net endogenous acid production, by sex

From: Association of estimated dietary acid load with albuminuria in Japanese adults: a cross-sectional study

  Quartile of net endogenous acid productiona, Men P value for linear trend Quartile of net endogenous acid production, Women P value for linear trend
Q1 (< 34.2 mEq/day) Q2 (34.2 to 43.3 mEq/day) Q3 (43.4 to 53.3 mEq/day) Q4 (≥53.4 mEq/day) Q1 (< 27.7 mEq/day) Q2 (27.7 to 34.9 mEq/day) Q3 (35.0 to 43.5 mEq/day) Q4 (≥43.6 mEq/day)
N 813 812 812 813   858 859 859 858  
PRALb, mEq/day −18.7 (−27.5, −12.6) −2.2 (−5.6, 0.8) 7.0 (4.6, 9.6) 17.7 (14.0, 23.5) < 0.0001 −32.8 (−44.1, − 25.3) −14.6 (− 18.6, −11.0) −2.9 (−6.0, 0.1) 10.1 (6.1, 16.7) < 0.0001
Age, years 70.1 ± 9.8 69.8 ± 10.0 68.6 ± 10.3 68.2 ± 10.8 < 0.0001 67.7 ± 8.8 68.6 ± 8.9 67.9 ± 9.8 68.8 ± 10.8 0.0613
Body mass index, kg/m2 22.9 ± 2.7 22.9 ± 2.9 22.8 ± 2.8 22.8 ± 2.9 0.2473 22.2 ± 3.1 22.6 ± 3.1 22.4 ± 3.3 22.5 ± 3.4 0.1091
Total physical Activityc, MET-hour/day 42.0 (37.2, 49.0) 41.3 (36.8, 47.8) 40.8 (36.8, 48.3) 41.3 (36.1, 48.3) 0.0894d 39.9 (36.9, 45.2) 39.0 (36.1, 43.8) 38.6 (36.0, 43.2) 38.3 (35.4, 43.5) < 0.0001d
Smoking status      < 0.0001      0.4917
 Never-smoker 194 (23.9) 175 (21.6) 178 (21.9) 152 (18.7)   750 (87.4) 768 (89.4) 755 (87.9) 743 (86.6)  
 Past smoker 458 (56.3) 476 (58.6) 425 (52.3) 428 (52.6)   60 (7.0) 69 (8.0) 67 (7.8) 69 (8.0)  
 Current smoker 161 (19.8) 161 (19.8) 209 (25.7) 233 (28.7)   48 (5.6) 22 (2.6) 37 (4.3) 46 (5.4)  
Alcohol consumption, g ethanol/week      < 0.0001      0.5289
 None or rarely 221 (27.2) 178 (21.9) 180 (22.2) 194 (23.9)   566 (66.0) 551 (64.1) 573 (66.7) 595 (69.4)  
 1–149 223 (27.4) 226 (27.8) 196 (24.1) 180 (22.1)   240 (28.0) 252 (29.3) 223 (26.0) 208 (24.2)  
 150–299 168 (20.7) 192 (23.7) 191 (23.5) 170 (20.9)   34 (4.0) 36 (4.2) 40 (4.7) 31 (3.6)  
 300–449 115 (14.2) 129 (15.9) 122 (15.0) 128 (15.7)   13 (1.5) 12 (1.4) 15 (1.8) 15 (1.8)  
 450- 86 (10.6) 87 (10.7) 123 (15.2) 141 (17.3)   5 (0.6) 8 (0.9) 8 (0.9) 9 (1.1)  
eGFR, ml/min/1.73 m2 73.8 ± 15.3 74.3 ± 15.4 74.5 ± 16.1 75.1 ± 16.2 0.1098 74.3 ± 15.1 74.6 ± 14.4 74.6 ± 15.2 75.2 ± 16.2 0.2309
Urine albumin creatinine ratio, mg/mmol 1.02 (0.57, 2.37) 1.13 (0.57, 2.43) 1.02 (0.57, 2.37) 1.13 (0.68, 2.94) 0.0301d 1.36 (0.79, 2.49) 1.47 (0.79, 2.71) 1.47 (0.83, 3.05) 1.58 (0.90, 3.16) < 0.0001d
Systolic blood pressure, mmHg 130.7 ± 18.2 131.5 ± 18.0 130.0 ± 17.7 131.6 ± 18.1 0.7031 127.6 ± 17.8 129.1 ± 18.2 128.4 ± 17.3 128.9 ± 18.3 0.2208
Diastolic blood pressure, mmHg 76.2 ± 11.2 76.0 ± 10.8 76.6 ± 10.8 77.4 ± 10.7 0.0147 73.1 ± 10.8 73.4 ± 10.6 73.6 ± 10.3 72.9 ± 10.7 0.8475
Pulse pressure, mmHg 54.5 ± 13.6 55.5 ± 13.4 53.4 ± 13.7 54.1 ± 13.8 0.1494 54.5 ± 12.9 55.7 ± 13.6 54.9 ± 13.1 56.0 ± 13.7 0.0723
Hypertension 444 (54.6) 479 (59.0) 456 (56.2) 473 (58.2) 0.3108 371 (43.2) 391 (45.5) 394 (45.9) 415 (48.4) 0.0387
Diabetes mellitus 79 (9.7) 69 (8.5) 69 (8.5) 74 (9.1) 0.6803 38 (4.4) 34 (4.0) 39 (4.5) 36 (4.2) 0.9699
Nutritientse
 Energy, kcal/day 2001.3 (1605.5, 2505.7) 2069.6 (1661.7, 2564.4) 2089.1 (1703.3, 2591.0) 2032.7 (1569.6, 2680.4) 0.0809d 1750.7 (1378.1, 2230.2) 1818.2 (1457.0, 2252.3) 1826.0 (1466.1, 2307.9) 1772.7 (1389.0, 2422.2) 0.0490d
 Protein, g/day 68.4 ± 14.1 70.9 ± 14.9 70.9 ± 14.4 71.6 ± 19.5 0.0001 67.5 ± 11.5 72.3 ± 11.5 74.9 ± 11.7 77.5 ± 16.3 < 0.0001
  Animal protein, g/day 26.4 (18.8, 35.2) 32.0 (22.8, 41.3) 33.8 (25.1, 44) 37.0 (24.4, 50.3) < 0.0001d 27.2 (20.0, 34.8) 34.1 (27.3, 41.6) 38.9 (31.3, 47.3) 43.5 (33.1, 55.5) < 0.0001d
  Plant protein, g/day 40.3 ± 7.9 37.1 ± 8.1 35.3 ± 7.9 32.1 ± 8.7 <  0.0001 38.8 ± 7.1 36.5 ± 7.4 35.1 ± 8.7 32.2 ± 9.1 <  0.0001
 Fat, g/day 53.3 ± 19.2 54.3 ± 18.5 54.0 ± 17.5 54.3 ± 22.8 0.3476 57.7 ± 15.8 60.0 ± 14.5 62.5 ± 15.2 64.7 ± 19.3 < 0.0001
 Carbohydrate, g/day 309.5 ± 50.2 295.2 ± 48.4 289.3 ± 50.0 276.7 ± 62.4 < 0.0001 287.6 ± 37.8 272.3 ± 35.1 259.9 ± 37.2 246.6 ± 48.9 < 0.0001
 Potassium, mg/day 3904.8 ± 956.1 3074.0 ± 666.9 2599.2 ± 542.4 2039.1 ± 616.5 < 0.0001 4539.0 ± 949.9 3697.8 ± 598.7 3238.4 ± 522.7 2591.3 ± 636.8 < 0.0001
 Calcium, mg/day 617.7 (482.4, 792.5) 538.3 (415.8, 694.1) 469.5 (362.0, 619.4) 355.0 (251.2, 484.5) < 0.0001d 706.8 (576.2, 885.2) 665.1 (539.9, 829.9) 626.0 (488.2, 788) 493.3 (374.6, 672.4) < 0.0001d
 Magnesium, mg/day 404.4 ± 99.3 338.0 ± 68.8 296.8 ± 59.2 248.4 ± 59.5 < 0.0001 426.1 ± 94.1 367.1 ± 63.6 333.9 ± 59.2 278.5 ± 58.0 < 0.0001
 Phosphorus, mg/day 1192.4 ± 274.8 1169.6 ± 295.0 1107.3 ± 251.1 1042.7 ± 283.9 < 0.0001 1211.0 ± 242.4 1217.7 ± 241.7 1210.4 ± 246.1 1150.1 ± 265.8 < 0.0001
 Salt, g/day 13.4 (10.3, 17.3) 11.5 (9.3, 14.1) 10.9 (8.7, 13.2) 9.8 (7.6, 12.2) < 0.0001d 14 (11.2, 17.5) 12.3 (9.9, 14.9) 11.0 (9.0, 13.5) 10.7 (8.7, 12.9) < 0.0001d
Food groupse
 Fish, g/day 44.1 (24.2, 69.9) 55.1 (31.6, 83.7) 58.3 (33.4, 92.2) 56.5 (28.0, 101.4) < 0.0001d 47.1 (28.2, 72.3) 63.9 (38.8, 89.7) 69.6 (42.3, 103.8) 73.6 (39.8, 116.6) < 0.0001d
 Meat, g/day 35.8 (18.6, 58.2) 46.8 (26.3, 73.6) 56.0 (30.0, 89.1) 67.0 (35.2, 115.4) < 0.0001d 35.4 (20.5, 54.8) 46.8 (26.8, 71.9) 58.3 (35.6, 84.7) 77.6 (42.6, 121.3) < 0.0001d
 Grain, g/day 577.6 ± 170.4 610.7 ± 163.0 640.0 ± 164.9 662.5 ± 200.2 < 0.0001 445.2 ± 134.5 483.2 ± 130.9 491.2 ± 132.8 521.4 ± 155.5 < 0.0001
 Legumes, g/day 61.2 (34.5, 103.6) 55.4 (32.7, 94.2) 51.1 (28.2, 81.6) 32.7 (15.2, 62.1) < 0.0001d 61.3 (35.3, 105.8) 66.5 (42.5, 105.8) 67.3 (39.5, 107.1) 52.0 (27.0, 89.3) < 0.0001d
 Egg, g/day 18.5 (7.9, 33.8) 21.4 (10.1, 38.0) 22.3 (10.2, 37.4) 23.4 (8.9, 47.1) < 0.0001d 17.1 (7.8, 30.8) 22.2 (12.2, 37.0) 24.2 (12.9, 39.2) 41.0 ± 61.0 < 0.0001d
 Vegetables, g/day 410.9 (259.6, 601.6) 247.8 (170.7, 315.2) 184.1 (121.9, 249.7) 108.8 (60.4, 164.1) < 0.0001d 558.1 (408.9, 759.6) 365.7 (274.9, 486.5) 277.1 (196.2, 361.9) 177.7 (115.5, 252.8) < 0.0001d
 Fruits, g/day 197.4 (101.6, 323.1) 129.9 (67.2, 206.1) 95.8 (48.8, 157.6) 43.6 (13.1, 89.5) < 0.0001d 314.1 (190.9, 469.7) 227.8 (145.7, 326.1) 166.8 (102.0, 247.9) 102.5 (47.0, 165.4) < 0.0001d
  1. eGFR estimated glomerular filtration rate, MET-hour metabolic equivalent task hours, PRAL potential renal acid load
  2. Values are as mean ± SD, median (IQR), or number (%)
  3. aNet endogenous acid production (mEq/day) = 54.5 × (protein [g/day]/potassium [mEq/day])-10.2
  4. bPotential renal acid load (mEq/day) = 0.4888 × protein (g/day) + 0.0366 × phosphorus (mg/day)-0.0205 × potassium (mg/day)-0.0125 × calcium (mg/day)-0.0263 × magnesium (mg/day)
  5. cThe number of subjects to be analyzed for physical activity decreased by 5 subjects in men and 8 subjects in women due to missing values
  6. dLinear trends for total physical activity, urine albumin creatinine ratio, energy, animal protein, calcium, salt, fish, meat, legume, egg, vegetable, and fruit intake were calculated after conversion to logarithmic form
  7. eNutrients and food groups were adjusted for energy intake by the residual method