title: Association between vitamin C deficiency and dialysis modalities.
abstract: OBJECTIVE
  We designed a cross-sectional study to investigate plasma vitamin C level in patients who underwent maintenance haemodialysis (MHD) and continuous ambulatory peritoneal dialysis (CAPD) to explore whether there is a difference in vitamin C deficiency between MHD patients and CAPD patients.
  
  
  METHODS
  This investigation included 382 dialysis patients without vitamin C supplement before the study. Demographic characteristics, laboratory tests, ascorbic acid and total plasma vitamin C level were measured. A linear regression model was built to explore the association between vitamin C deficiency and dialysis modalities after adjusting for age, dialysis vintage, gender, Charlson index, modality of dialysis and hsCRP.
  
  
  RESULTS
  The range of plasma vitamin C level was from 0.48 µg/mL to 31.16 µg/mL. 35.9% (n = 137) patients had severe vitamin C deficiency (<2 µg/mL). Plasma vitamin C level was inversely associated with age and dialysis vintage. After age and dialysis vintage were adjusted, vitamin C deficiency was associated with MHD. R square for model fitting was relatively low, which implied that there were other vitamin C influencing factors not included in the model.
  
  
  CONCLUSIONS
  Vitamin C deficiency is common in dialysis patients, especially in patients treated with MHD.
authors.affiliation: Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China.
authors.forename: Kunying
authors.initials: K
authors.lastname: Zhang
authors.forename: Jie
authors.initials: J
authors.lastname: Dong
authors.forename: Xuyang
authors.initials: X
authors.lastname: Cheng
authors.forename: Wenying
authors.initials: W
authors.lastname: Bai
authors.forename: Weiya
authors.initials: W
authors.lastname: Guo
authors.forename: Leiyun
authors.initials: L
authors.lastname: Wu
authors.forename: Li
authors.initials: L
authors.lastname: Zuo
mesh_terms: D000367:Age Factors; D000368:Aged; D001205:Ascorbic Acid / Q000097:blood*; D001206:Ascorbic Acid Deficiency / Q000097:blood / Q000453:epidemiology*; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis; D016009:Chi-Square Distribution; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010531:Peritoneal Dialysis, Continuous Ambulatory / Q000009:adverse effects*; D011228:Prealbumin / Q000032:analysis; D015995:Prevalence; D006435:Renal Dialysis / Q000009:adverse effects*; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors; D013997:Time Factors
chemical_list: D015415:Biomarkers; D011228:Prealbumin; D002097:C-Reactive Protein; D001205:Ascorbic Acid