Table 1 Basic characteristics of the study participants in China Health and Nutrition Survey (2009), stratified by sex and estimated glomerular filtration rate
|  | Men (n = 3644) | Women (n = 4154) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
eGFR ≥60 (n = 3411) | eGFR <60 (n = 233) | p-valuea | eGFR ≥60 (n = 3755) | eGFR <60 (n = 399) | p-valuea | |||||
Age (in years), mean [SD] | 49.6 | 14.4 | 71.5 | 9.7 | < 0.001 | 49.0 | 13.7 | 69.4 | 10.7 | < 0.001 |
Education, n (%) | ||||||||||
  Primary school or less | 1130 | 33.1 | 127 | 54.5 | < 0.001 | 1838 | 49.0 | 322 | 80.7 | < 0.001 |
 Junior high school | 1327 | 38.9 | 53 | 22.8 |  | 1142 | 30.4 | 44 | 11.0 |  |
 Senior high school | 482 | 14.1 | 16 | 6.9 |  | 383 | 10.2 | 12 | 3.0 |  |
 Post-secondary education | 472 | 13.8 | 37 | 15.9 |  | 392 | 10.4 | 21 | 5.3 |  |
Household income (yuan), n (%) | ||||||||||
 Low (0–6533) | 1087 | 31.9 | 78 | 33.5 | 0.049 | 1284 | 34.2 | 152 | 38.1 | 0.280 |
 Middle (6542–13,859) | 1164 | 34.1 | 62 | 26.6 |  | 1250 | 33.3 | 122 | 30.6 |  |
 High (13,862–378,571) | 1160 | 34.0 | 93 | 39.9 |  | 1221 | 32.5 | 125 | 31.3 |  |
Health-related behaviors | ||||||||||
 Alcohol consumption frequency, n (%) | 1883 | 55.2 | 67 | 28.8 | < 0.001 | 223 | 5.9 | 20 | 5.0 | 0.454 |
 Current Smoking, n (%) | 1923 | 56.4 | 89 | 38.2 | < 0.001 | 136 | 3.6 | 26 | 6.5 | 0.005 |
 Weekly physical activity (METs), mean [SD] | 224.1 | 216.7 | 81.0 | 119.6 | < 0.001 | 229.6 | 215.9 | 110.8 | 137.7 | < 0.001 |
 Energy intake (kcal), mean [SD] | 2335.5 | 600.3 | 2048.7 | 577.0 | < 0.001 | 1996.0 | 545.9 | 1793.9 | 518.3 | < 0.001 |
 Protein intake (g), mean [SD] | 71.7 | 22.5 | 62.5 | 20.0 | < 0.001 | 61.9 | 20.3 | 55.1 | 19.2 | < 0.001 |
 Sodium intake (g), mean [SD] | 4.9 | 2.6 | 4.4 | 2.6 | 0.009 | 4.6 | 2.6 | 4.2 | 2.4 | 0.004 |
 Potassium intake (g), mean [SD] | 1.7 | 0.6 | 1.5 | 0.6 | < 0.001 | 1.6 | 0.6 | 1.4 | 0.5 | < 0.001 |
 Sodium-to-potassium ratio, mean [SD] | 3.0 | 1.9 | 3.2 | 2.2 | 0.266 | 3.1 | 2.1 | 3.3 | 2.1 | 0.122 |
Cardiometabolic risk factors | ||||||||||
 BMI, n (%) |  |  |  |  |  |  |  |  |  |  |
  < 24.0 | 2028 | 59.5 | 147 | 63.1 | 0.547 | 2254 | 60.0 | 238 | 59.7 | 0.245 |
 24.0–27.99 | 1087 | 31.9 | 68 | 29.2 |  | 1108 | 29.5 | 109 | 27.3 |  |
  ≥ 28.0 | 296 | 8.7 | 18 | 7.7 |  | 393 | 10.5 | 52 | 13.0 |  |
 Hypertension, n (%) | 1078 | 31.6 | 150 | 64.4 | < 0.001 | 971 | 25.9 | 225 | 56.4 | < 0.001 |
 Diabetes mellitus, n (%) | 392 | 11.5 | 49 | 21.0 | < 0.001 | 324 | 8.6 | 103 | 25.8 | < 0.001 |
 High LDL, n (%) | 938 | 27.5 | 77 | 33.1 | 0.068 | 1164 | 31.0 | 209 | 52.4 | < 0.001 |
Urbanization index, mean [SD] | 66.3 | 19.4 | 73.6 | 19.7 | < 0.001 | 66.7 | 19.4 | 72.0 | 19.2 | < 0.001 |
eGFR, mean [SD] | 83.8 | 18.6 | 50.7 | 9.9 | - | 84.5 | 13.4 | 54.1 | 9.3 | - |