Prevalence and Predictors of Insufficient Plasma Vitamin C in a Subtropical Region and Its Associations with Risk Factors of Cardiovascular Diseases: A Retrospective Cross-Sectional Study.

Background: to evaluate the prevalence and predictors of insufficient plasma vitamin C among adults in a subtropical region and its associations with cardiovascular disease risk factors including dyslipidemia and lipid-independent markers, namely homocysteine, high-sensitivity C-reactive protein (hs-CRP) and lipoprotein(a). Methods: Data of this retrospective cross-sectional study were extracted from electronic medical database of a Medical Center. Based on plasma vitamin C status, subjects were split into two groups—subjects with sufficient and insufficient plasma vitamin C levels (<50 µmol/L, ≤8.8 mg/L). Results: Prevalence of insufficient plasma vitamin C in 3899 adults was 39%. Multivariate logistic regression identified male gender, high body mass index, age 20−39, and winter/spring as independent predictors of insufficient vitamin C among all subjects. Greater proportions of subjects with insufficient plasma vitamin C had lower high-density lipoprotein cholesterol levels and elevated levels of triglyceride, homocysteine and hs-CRP (all p < 0.001). There were no differences in total cholesterol, low-density lipoprotein cholesterol and lipoprotein(a) between groups. Conclusions: There was a high prevalence of insufficient plasma vitamin C in the subtropical region, which indicates that insufficient plasma vitamin C remains a public health issue. Further study is needed to confirm these findings and to determine the underlying mechanisms.