Table 1.

Participant characteristics by quartiles of net endogenous acid production

CharacteristicNet Endogenous Acid Production (mEq/d)P
<39.339.3–52.953.0–69.9≥70.0
Number2477240324112490
Age (yr)50.7 (0.45)48.4 (0.46)44.0 (0.42)39.8 (0.41)<0.001
Women (%)58.6 (1.1)49.0 (1.3)45.9 (1.5)43.6 (1.2)<0.001
Race/ethnicity (%)<0.001
 Non-Hispanic white78.1 (1.7)76.8 (1.5)71.9 (2.0)64.1 (2.3)
 Mexican American5.4 (0.7)7.9 (1.1)7.8 (1.0)8.7 (1.4)
 Non-Hispanic black7.3 (0.9)7.0 (0.7)9.4 (1.0)17.2 (1.7)
 Other9.2 (1.4)8.3 (0.9)10.8 (1.5)10.0 (1.3)
Body mass index (kg/m2; %)<0.001
 <18.5 (underweight)2.2 (0.4)1.4 (0.3)0.9 (0.2)1.5 (0.3)
 18.5–24.9 (normal)37.5 (1.3)33.4 (1.4)30.5 (1.5)29.3 (1.1)
 25–29.9 (overweight)35.3 (1.2)37.3 (1.3)35.5 (1.1)33.1 (1.4)
 ≥30 (obese)24.8 (1.1)27.7 (1.3)33.0 (1.8)35.9 (1.0)
Poverty (<100% poverty index; %)11.2 (0.9)11.5 (1.0)11.1 (0.9)16.5 (1.1)<0.001
Less than high school diploma (%)18.4 (1.3)17.5 (1.2)16.7 (0.9)21.6 (1.3)0.11
Smoking (%)<0.001
 Never50.7 (1.5)50.7 (1.8)51.5 (1.5)50.9 (1.9)
 Former28.7 (1.3)27.8 (1.5)23.4 (1.3)19.9 (1.1)
 Current20.6 (1.2)21.5 (1.2)25.1 (1.4)29.2 (1.7)
Dietary protein (g/d)60.6 (0.9)81.3 (1.2)92.7 (1.2)99.3 (1.1)<0.001
Dietary potassium (mEq/d)82.0 (1.2)78.4 (1.2)71.1 (1.0)54.6 (0.7)<0.001
Diuretic use (%)11.5 (0.8)10.5 (1.0)8.7 (0.8)8.7 (0.8)0.001
Hypertension (%)43.5 (1.7)42.1 (1.7)36.1 (1.5)34.9 (1.3)<0.001
Cardiovascular disease (%)10.6 (0.8)7.9 (0.9)7.6 (0.7)6.0 (0.6)<0.001
Diabetes mellitus (%)7.7 (0.5)6.7 (0.7)6.8 (0.7)6.2 (0.6)0.03
Estimated GFR (ml/min per 1.73 m2; %)<0.001
 ≥1206.8 (0.6)8.1 (0.7)10.1 (0.7)16.6 (1.2)
 90–11943.5 (1.7)46.7 (1.3)52.4 (1.3)50.9 (1.6)
 60–8940.5 (1.5)38.9 (1.5)33.4 (1.4)28.6 (1.6)
 45–596.7 (0.6)4.5 (0.5)2.8 (0.3)2.8 (0.3)
 30–441.9 (0.3)1.4 (0.2)0.9 (0.2)1.0 (0.2)
 15–290.6 (0.1)0.3 (0.1)0.3 (0.1)0.07 (0.04)
Urine albumin–creatinine ratio (mg/g; %)0.36
 <3090.8 (0.8)90.5 (0.9)92.9 (0.7)91.1 (0.8)
 30–3008.3 (0.8)8.3 (0.9)6.1 (0.6)7.6 (0.7)
 >3001.0 (0.2)1.2 (0.3)1.0 (0.2)1.3 (0.3)
Serum albumin (g/dl)4.36 (1.2)4.38 (1.0)4.37 (1.2)4.37 (1.1)0.48
C-reactive protein (mg/dl; %)0.02
 <0.3671.1 (1.1)71.2 (1.2)69.7 (1.3)66.8 (1.2)
 0.36–0.9919.7 (0.8)20.4 (1.1)20.8 (1.0)24.0 (1.1)
 ≥19.2 (0.8)8.4 (0.7)9.5 (0.9)9.2 (0.7)
  • Data are expressed as mean (SEM) or percent (SEM).