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Table 1 Characteristics of study participants by estimated Net Acid Excretion quintiles

From: Dietary acid load and chronic kidney disease among adults in the United States

Characteristics Net acid excretion (mEq/day) P- Value*
Quintile 1 (min- 37.35) Quintile 2 (37.35–49.62) Quintile 3 (49.62–60.89) Quintile 4 (60.89–75.65) Quintile 5 (75.65-max)  
Age category (in years), (%)       <0.0001
20– < 40 717 (29.2) 834 (33.9) 845 (34.4) 887 (36.1) 1122 (45.6)  
40– < 60 776 (31.6) 654 (26.6) 719 (29.2) 758 (30.8) 774 (31.5)  
60– < 70 447 (18.2) 406 (16.5) 380 (15.4) 385 (15.7) 292 (11.9)  
≥70 517 (21.0) 565 (23.0) 516 (21.0) 429 (17.4) 270 (10.9)  
Age, continuous (mean ± SD) 47.1 ± 0.50 46.7 ± 0.61 46.9 ± 0.64 45.9 ± 0.48 42.9 ± 0.44 0.001
Gender, (%)       <0.0001
Male 879 (35.8) 1246 (50.7) 1407 (57.2) 1477 (60.1) 1442 (58.7)  
Female 1579 (64.2) 1213 (49.3) 1053 (42.8) 982 (39.9) 1015 (41.3)  
Race/Ethnicity, %       <0.0001
Non-Hispanic Blacks 381 (17.0) 342 (15.0) 395 (17.5) 458 (20.1) 639 (28.3)  
Mexican Americans 468 (20.9) 488 (21.4) 564 (25.0) 615 (27.1) 685 (30.3)  
Non-Hispanic Whites 1390 (62.1) 1450 (63.6) 1298 (57.5) 1201 (52.8) 937 (41.4)  
Poverty Income Ratio, %       <0.0001
≤2 848 (37.2) 880 (39.0) 923 (41.2) 1101 (48.4) 1228 (54.9)  
2– ≤ 3 389 (17.1) 335 (14.9) 386 (17.2) 338 (14.8) 365 (16.3)  
3– ≤ 4 278 (12.2) 326 (14.5) 315 (14.0) 268 (11.8) 229 (10.3)  
>4 762 (33.5) 713 (31.6) 618 (27.6) 570 (25.0) 413 (18.5)  
Education History, %       0.002
<High School 563 (22.9) 637 (25.9) 727 (29.6) 841 (34.3) 1104 (44.9)  
High School/Some College 1308 (53.3) 1269 (51.6) 1225 (50.0) 1201 (48.9) 1084 (44.2)  
>College 583 (23.8) 551 (22.5) 500 (20.4) 413 (16.8) 267 (10.9)  
Smoker, %       0.004
Current 570 (23.2) 527 (21.4) 456 (18.5) 511 (20.8) 594 (24.2)  
Past 647 (26.4) 695 (28.3) 689 (28.0) 664 (27.1) 607 (24.7)  
Never 1236 (50.4) 1235 (50.3) 1315 (53.5) 1280 (52.1) 1253 (51.1)  
Diabetes, %       0.11
Yes 284 (11.5) 298 (12.1) 305 (12.4) 302 (12.3) 254 (10.3)  
No 2175 (88.5) 2160 (87.9) 2155 (87.6) 2157 (87.7) 2203 (89.7)  
Hypertension, %       0.27
Yes 855 (34.8) 864 (35.2) 845 (34.3) 824 (33.5) 731 (29.8)  
No 1604 (65.2) 1594 (64.8) 1615 (65.7) 1635 (66.5) 1726 (70.2)  
Cardiac Disease, %       0.005
Yes 367 (15.0) 296 (12.1) 279 (11.4) 220 (9.0) 182 (7.4)  
No 2078 (85.0) 2146 (87.9) 2172 (88.6) 2231 (91.0) 2267 (92.6)  
Total Caloric Intake, %       <0.0001
<2000 Kcal/day 2172 (88.4) 1669 (67.9) 1068 (43.4) 613 (24.9) 322 (13.1)  
≥2000 Kcal/day 286 (11.6) 790 (32.1) 1392 (56.6) 1846 (75.1) 2135 (86.9)  
  1. Poverty Income Ratio = a ratio of family income to poverty threshold.
  2. HTN = Hypertension defined as self-reported, avg BP > 140/90 or use of medications.
  3. Diabetes defined as self-reported or hemoglobin A1c (A1c) ≥ 6.5%.
  4. *By X2test for categorical variables and one-way ANOVA for continuous variables.