Table 1.
Participant Characteristics by Quartiles of Serum Bicarbonate
| Characteristic | Serum Bicarbonate (mEq/L)
|
P | |||
|---|---|---|---|---|---|
| < 24 | 24–25 | 25.1–26.9 | ≥ 27 | ||
| Number | 833 | 661 | 747 | 473 | |
| Age (years) | 33.8 (0.4) | 33.7 (0.5) | 34.3 (0.4) | 34.2 (0.6) | 0.43 |
| Women (%) | 60.8 (3.2) | 50.0 (2.8) | 40.1 (2.0) | 26.6 (2.6) | <0.001 |
| Race/Ethnicity (%) | 0.14 | ||||
| Non-Hispanic White | 70.8 (2.2) | 73.0 (2.3) | 69.9 (2.5) | 76.4 (2.0) | |
| Mexican American | 11.3 (2.3) | 9.4 (1.2) | 10.5 (1.3) | 5.4 (0.9) | |
| Non-Hispanic Black | 8.2 (1.3) | 10.2 (1.7) | 11.1 (1.3) | 10.5 (1.5) | |
| Body-mass index (kg/m2) | 28.2 (0.3) | 27.0 (0.3) | 26.7 (0.2) | 25.5 (0.2) | <0.001 |
| % Lean body mass | 62.5 (0.3) | 65.0 (0.4) | 66.7 (0.4) | 69.1 (0.5) | <0.001 |
| Poverty (<100% poverty index, %) | 12.8 (1.6) | 12.3 (1.9) | 11.0 (1.4) | 7.2 (1.5) | 0.01 |
| Less than high-school diploma (%) | 12.1 (1.3) | 13.5 (1.5) | 14.6 (1.6) | 11.0 (2.3) | 0.97 |
| Activity Level (MET-min/wk, %) | 0.08 | ||||
| 0 | 9.5 (1.1) | 8.5 (1.1) | 12.0 (1.6) | 6.8 (1.4) | |
| < 500 | 22.9 (2.1) | 19.7 (1.8) | 17.7 (1.7) | 17.6 (2.2) | |
| 500–2000 | 35.1 (1.9) | 37.9 (3.2) | 38.8 (2.1) | 35.6 (2.0) | |
| > 2000 | 32.5 (2.6) | 33.8 (2.6) | 31.5 (2.3) | 40.0 (2.8) | |
| Smoking (%) | 0.24 | ||||
| Never | 55.0 (3.1) | 55.0 (2.4) | 58.4(2.3) | 61.6 (2.9) | |
| Former | 15.4 (1.7) | 17.4 (2.0) | 15.5 (1.4) | 17.2 (1.7) | |
| Current | 29.6 (2.6) | 27.6 (2.0) | 25.9 (2.3) | 21.3 (2.4) | |
| Estimated NEAP (mEq/day) | 60.4 (1.2) | 62.9 (1.0) | 59.8 (1.2) | 55.1 (1.1) | 0.005 |
| Fasting length ≤2 hours (%) | 1.4 (0.4) | 2.5 (0.8) | 2.7 (0.5) | 4.4 (1.9) | 0.04 |
| Soft drink consumption (%) | 0.003 | ||||
| None | 45.6 (3.2) | 56.7 (3.2) | 43.9 (2.6) | 55.9 (3.6) | |
| 1 | 31.9 (2.9) | 23.2 (3.0) | 27.9 (1.9) | 27.7 (2.8) | |
| ≥ 2 | 22.5 (1.9) | 20.1 (2.4) | 28.2 (1.8) | 16.5 (2.7) | |
| Diuretic use (%) | 0.9 (0.5) | 1.0 (0.4) | 2.3 (0.9) | 1.4 (0.6) | 0.23 |
| Cholesterol-lowering medication (%) | 1.4 (0.5) | 2.2 (0.9) | 2.6 (0.8) | 1.7 (0.9) | 0.59 |
| Hypertension (%) | 19.8 (1.9) | 9.6 (1.5) | 13.6 (1.7) | 10.9 (1.9) | 0.002 |
| Diabetes Mellitus (%) | 1.7 (0.6) | 0.9 (0.4) | 1.5 (0.6) | 1.2 (0.6) | 0.64 |
| Systolic Blood Pressure (mm Hg) | 115.5 (0.6) | 115.0 (0.7) | 114.7 (0.7) | 115.3 (0.7) | 0.60 |
| eGFR (mL/min/1.73m2) | 103.3 (1.0) | 102.6 (0.9) | 102.8 (0.8) | 102.8 (1.2) | 0.73 |
| UACR > 30 mg/g (%) | 4.9 (0.8) | 5.5 (1.2) | 3.4 (1.0) | 2.9 (1.2) | 0.13 |
| Serum anion gap (mEq/L) | 11.6 (0.3) | 10.4 (0.2) | 9.7 (0.2) | 8.5 (0.2) | <0.001 |
| Serum albumin (g/dL) | 4.37 (0.01) | 4.43 (0.02) | 4.46 (0.02) | 4.56 (0.03) | <0.001 |
| Serum calcium (mg/dL) | 9.41 (0.02) | 9.52 (0.02) | 9.51 (0.02) | 9.54 (0.04) | 0.001 |
| Serum phosphate (mg/dL) | 3.71 (0.03) | 3.75 (0.03) | 3.67 (0.03) | 3.70 (0.03) | 0.44 |
| Hemoglobin (g/dL) | 14.48 (0.11) | 14.60 (0.10) | 14.66 (0.07) | 14.94 (0.08) | 0.005 |
| Total cholesterol (mg/dL) | 191.3 (1.6) | 191.5 (1.8) | 193.2 (2.3) | 193.6 (2.6) | 0.38 |
| HDL cholesterol (mg/dL) | 50.1 (0.8) | 52.5 (0.8) | 50.7 (0.7) | 52.4 (1.0) | 0.16 |
| C-reactive protein ≥ 1.0 mg/dL (%) | 7.8 (0.9) | 5.8 (0.9) | 4.9 (1.0) | 5.2 (1.2) | 0.04 |
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).