Table 4.
Associations between serum vitamin C level and significant liver fibrosis (n = 4494), NHANES 2017–2018.
| Significant liver fibrosis (Yes, n = 1071) | Model 1 OR (95% CI), P | Model 2 OR (95% CI), P | Model 3 OR (95% CI), P | |
|---|---|---|---|---|
| Quartiles of vitamin C, umol/L | ||||
| Q1 (<30.9) | 357 | Reference | Reference | Reference |
| Q2 (30.9–50.5) | 280 | 0.584 (0.444,0.769) <0.001 |
0.590 (0.446,0.780) <0.001 |
0.606 (0.451,0.814) 0.001 |
| Q3 (50.5–67.0) | 229 | 0.470 (0.346,0.638) <0.001 |
0.468 (0.344,0.638) <0.001 |
0.543(0.391,0.752) <0.001 |
| Q4 (≥67.0) | 205 | 0.458 (0.334,0.628) <0.001 |
0.468 (0.333,0.657) <0.001 |
0.597 (0.400,0.889) 0.011 |
| P trend | - | <0.001 | <0.001 | <0.001 |
| Sensitivity analysis after exclusion of participants with dietary vitamin C supplement (None, n = 2909) | ||||
| Quartiles of vitamin C, umol/L | N = 705 | |||
| Q1 (<30.9) | 304 | Reference | Reference | Reference |
| Q2 (30.9–50.5) | 184 | 0.494 (0.362,0.675) <0.001 |
0.512 (0.373,0.703) <0.001 |
0.531 (0.379,0.743) <0.001 |
| Q3 (50.5–67.0) | 139 | 0.471 (0.326,0.681) <0.001 |
0.485 (0.334,0.704) <0.001 |
0.584 (0.394,0.866) 0.007 |
| Q4 (≥67.0) | 78 | 0.443 (0.274,0.717) 0.001 |
0.499 (0.304,0.820) 0.006 |
0.719 (0.414,1.247) 0.240 |
| P trend | - | <0.001 | <0.001 | <0.001 |
Model 1: Non-adjusted model; Model 2 adjusted for: gender; age; race; Model 3 adjusted for: gender; age; race; education; alcohol; diabetes; HBV infection; HCV infection; physical activity status; serum cotinine levels; dietary vitamin C supplement; dietary vitamin C intake by food; BMI, and poverty income ratio.
NHANES, National Health and Nutrition Examination Survey; BMI, body mass index; OR, odds ratio; 95% CI, 95% confidence interval.