Table 1

Baseline characteristics of participants by quartile of serum bicarbonate

CharacteristicsSerum bicarbonate (mmol/L)P values
Quartile 1
(<25.8)
Quartile 2
(25.8–26.8)
Quartile 3
(26.8–28.0)
Quartile 4
(≥28.0)
n1340142613221230
Male (%)47.143.139.943.30.003**
Age (years, mean (SD))23.5 (2.2)22.4 (2.0)22.3 (1.8)22.2 (2.1)<0.001***
Married (%)85.786.184.284.00.002**
Nationality: Han (%)90.391.291.490.60.002**
Current smoking (%)15.614.714.315.0<0.001***
Body mass index (kg/m2, mean (SD))23.5 (2.2)22.4 (2.0)22.3 (1.8)22.2 (2.1)0.001**
Hypertension (%)4.83.10.91.5<0.001***
Systolic blood pressure (mm Hg, mean (SD))110.5 (8.6)110.1 (7.9)110.2 (7.6)110.6 (8.7)NS
Diastolic blood pressure (mm Hg, mean (SD))80.8 (6.7)70.4 (9.2)70.2 (6.3)70.7 (8.6)<0.001***
ALT (U/L, mean (SD))17.3 (12.4)17.8 (10.9)18.4 (8.5)18.5 (10.2)0.005**
AST (U/L, mean (SD))25.1 (4.2)24.3 (4.6)24.1 (4.7)24.8 (3.6)0.03*
Serum creatinine (µmol/L, mean (SD))65.6 (11.3)66.7 (13.2)67.5 (12.2)70.5 (12.4)<0.001***
Fasting blood glucose (mmol/L, mean (SD))5.0 (0.2)5.1 (0.2)5.1 (0.2)5.1 (0.2)0.02*
Total cholesterol (mmol/L, mean (SD))4.6 (0.6)4.6 (0.5)4.7 (0.5)4.7 (0.6)0.01*
Triglyceride (mmol/L, mean (SD))0.9 (0.5)1.0 (0.5)1.0 (0.5)1.1 (0.5)0.03*
HDL (mmol/L, mean (SD))1.5 (0.3)1.5 (0.3)1.5 (0.3)1.5 (0.3)NS
LDL (mmol/L, mean (SD))2.8 (0.5)2.8 (0.5)2.8 (0.5)2.9 (0.5)0.04*
Serum bicarbonate (mmol/L, mean (SD))25.4 (1.1)26.5 (0.9)27.7 (0.6)28.8 (0.7)<0.001***
  • Data are mean (SD) unless otherwise indicated.

  • P values are from one-way analysis of variance (ANOVA) for those reported as means and χ2 test for those reported as percentages. P values are divided into four categories and footnoted:

  • *P<0.05; **P<0.01; ***P<0.001

  • ALT, alanine aminotransferase; AST, aspartate aminotransferase; HDL, high-density lipoprotein; LDL, low-density lipoprotein; NS, no significance.