Table 2.
Participant Characteristics by Quartiles of Serum Anion Gap
| Characteristic | Serum Anion Gap (mEq/L)
|
P | |||
|---|---|---|---|---|---|
| < 8.60 | 8.60–10.25 | 10.26–11.90 | ≥ 11.91 | ||
| Number | 653 | 735 | 691 | 635 | |
| Age (years) | 34.7 (0.5) | 33.6 (0.5) | 33.8 (0.4) | 33.8 (0.4) | 0.26 |
| Women (%) | 42.5 (2.0) | 47.8 (2.5) | 48.3 (3.4) | 47.0 (2.3) | 0.18 |
| Race/Ethnicity (%) | 0.46 | ||||
| Non-Hispanic White | 75.4 (2.4) | 68.8 (2.6) | 73.6 (2.2) | 71.0 (2.8) | |
| Mexican American | 8.9 (1.3) | 10.2 (1.5) | 9.2 (1.4) | 9.8 (2.1) | |
| Non-Hispanic Black | 9.5 (1.3) | 11.5 (1.5) | 9.4 (1.3) | 9.0 (1.9) | |
| Body-mass index (kg/m2) | 26.4 (0.3) | 26.9 (0.2) | 27.1 (0.3) | 27.8 (0.4) | 0.001 |
| % Lean body mass | 66.6 (0.4) | 65.3 (0.4) | 65.2 (0.4) | 64.5 (0.4) | <0.001 |
| Poverty (<100% poverty index, %) | 7.3 (1.2) | 12.6 (1.5) | 11.9 (1.4) | 12.9 (2.2) | 0.05 |
| Less than high-school diploma (%) | 12.0 (2.3) | 13.4 (1.4) | 14.5 (1.4) | 11.5 (1.6) | 0.98 |
| Activity Level (MET-min/wk, %) | 0.58 | ||||
| 0 | 7.2 (1.0) | 10.2 (1.4) | 11.9 (1.6) | 8.2 (1.2) | |
| < 500 | 20.1 (2.5) | 20.8 (2.0) | 19.0 (2.2) | 19.2 (2.6) | |
| 500–2000 | 37.1 (2.5) | 36.8 (2.8) | 37.2 (2.5) | 36.1 (2.7) | |
| > 2000 | 35.6 (2.0) | 32.2 (2.5) | 31.9 (1.8) | 36.6 (3.4) | |
| Smoking (%) | 0.16 | ||||
| Never | 61.9 (2.7) | 54.7 (2.2) | 56.7 (2.7) | 55.2 (4.1) | |
| Former | 17.3 (1.7) | 17.5 (1.7) | 14.2 (1.7) | 16.0 (2.0) | |
| Current | 20.8 (2.4) | 27.8 (1.6) | 29.1 (2.4) | 28.8 (3.2) | |
| Estimated NEAP (mEq/day) | 58.7 (1.3) | 59.0 (1.3) | 60.5 (1.3) | 61.3 (1.4) | 0.16 |
| Fasting length ≤2 hours (%) | 3.4 (1.2) | 3.1 (0.9) | 1.5 (0.5) | 2.3 (0.7) | 0.21 |
| Soft drink consumption (%) | 0.004 | ||||
| None | 55.6 (3.6) | 56.6 (3.3) | 44.8 (3.1) | 41.7 (3.6) | |
| 1 | 26.4 (2.8) | 25.2 (2.8) | 28.7 (2.4) | 31.7 (2.7) | |
| ≥ 2 | 17.9 (2.0) | 18.2 (2.3) | 26.5 (2.2) | 26.6 (2.8) | |
| Diuretic use (%) | 1.0 (0.4) | 1.4 (0.8) | 1.4 (0.6) | 1.7 (0.7) | 0.36 |
| Cholesterol-lowering medication (%) | 2.2 (0.9) | 2.1 (0.7) | 2.0 (0.6) | 1.6 (0.6) | 0.58 |
| Hypertension (%) | 10.0 (1.3) | 13.4 (1.9) | 16.1 (1.8) | 16.8 (2.3) | 0.003 |
| Diabetes Mellitus (%) | 0.2 (0.1) | 1.5 (0.6) | 1.1 (0.2) | 2.6 (0.8) | 0.005 |
| Systolic Blood Pressure (mm Hg) | 113.3 (0.6) | 114.8 (0.7) | 116.0 (0.6) | 116.5 (0.8) | 0.001 |
| eGFR (mL/min/1.73m2) | 103.1 (1.1) | 103.8 (0.9) | 101.9 (0.8) | 102.8 (1.0) | 0.51 |
| UACR > 30 mg/g (%) | 2.9 (0.8) | 3.6 (0.8) | 5.9 (1.2) | 4.9 (1.2) | 0.05 |
| Serum bicarbonate (mEq/L) | 26.1 (0.2) | 24.9 (0.1) | 24.1 (0.2) | 23.3 (0.2) | <0.001 |
| Serum albumin (g/dL) | 4.48 (0.02) | 4.43 (0.02) | 4.43 (0.02) | 4.44 (0.02) | 0.40 |
| Serum calcium (mg/dL) | 9.47 (0.03) | 9.49 (0.02) | 9.49 (0.02) | 9.50 (0.04) | 0.47 |
| Serum phosphate (mg/dL) | 3.65 (0.03) | 3.72 (0.03) | 3.68 (0.03) | 3.79 (0.03) | 0.01 |
| Hemoglobin (g/dL) | 14.55 (0.09) | 14.50 (0.08) | 14.71 (0.09) | 14.81 (0.09) | 0.008 |
| Total cholesterol (mg/dL) | 187.9 (1.5) | 190.4 (2.0) | 193.6 (2.1) | 197.5 (2.6) | 0.003 |
| HDL cholesterol (mg/dL) | 51.6 (0.6) | 52.3 (0.7) | 51.4 (0.9) | 49.6 (0.8) | 0.09 |
| C-reactive protein ≥ 1.0 mg/dL (%) | 3.2 (1.0) | 5.3 (1.2) | 6.9 (0.9) | 9.0 (1.6) | 0.001 |
Abbreviations: MET, metabolic equivalent; NEAP, net endogenous acid production; eGFR, estimated glomerular filtration rate; UACR, urinary albumin-creatinine ratio.
Data are expressed as mean (standard error (SE)) or percent (SE).