Table 5.

Associations between serum vitamin C level and liver cirrhosis, NHANES 2017–2018.

	Liver cirrhosis (Yes, n = 138)	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)	61	Reference	Reference	Reference
Q2 (30.9–50.5)	28	0.338 (0.169,0.678) 0.002	0.356 (0.178,0.715) 0.004	0.276 (0.142,0.534) <0.001
Q3 (50.5–67.0)	28	0.247 (0.128,0.477) <0.001	0.251 (0.130,0.483) <0.001	0.290 (0.139,0.605) 0.001
Q4 (≥67.0)	21	0.288 (0.111,0.748) 0.011	0.303 (0.103,0.892) 0.030	0.312 (0.136,0.717) 0.006
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 = 85
Q1 (<30.9)	51	Reference	Reference	Reference
Q2 (30.9–50.5)	14	0.203 (0.094,0.436) <0.001	0.212 (0.101,0.441) <0.001	0.206 (0.095,0.444) <0.001
Q3 (50.5–67.0)	16	0.236 (0.102,0.546) 0.001	0.246(0.108,0.564) 0.001	0.279 (0.095,0.821) 0.020
Q4 (≥67.0)	4	0.108 (0.032,0.358) <0.001	0.112(0.034,0.370) <0.001	0.146 (0.042,0.509) 0.003
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.