title: Effect of vitamin C on parathyroid hormone in hemodialysis patients with mild to moderate secondary hyperparathyroidism.
abstract: BACKGROUND
  In end-stage renal disease, there is a high incidence of secondary hyperparathyroidism. It is proposed that increasing vitamin C levels by dietary supplementation results in a decrease of parathyroid hormone (PTH) in vitamin C-deficient hemodialysis patients with secondary hyperparathyroidism. The aim of this study was the evaluation of vitamin C administration for reduction of serum PTH level in hemodialysis patients.
  
  
  METHODS
  Twenty-one hemodialysis patients with serum PTH levels less than 550 pg/mL (but more than 200 pg/mL) were administered intravenous vitamin C, 200 mg, 3 times per week for 3 months. Blood samples for measurement of PTH were obtained at the beginning of the hemodialysis session every month for three months.
  
  
  RESULTS
  The mean level of serum biointact PTH was 333.3 ± 141.3 pg/mL (reference range, 7 pg/mL to 82 pg/mL) at baseline, and it decreased to 256.5 ± 137.2 pg/mL at 1 month (P = .03). The mean PTH level was also lower than the baseline value at 2 months (260.1 ± 123.2 pg/mL, P = .03), while it increased to 328.9 ± 176.0 pg/mL at 3 months, which was still slightly lower than the baseline level (P = .13). In 15 patients (71.4%), serum levels of PTH were lower than the baseline at months 1 to 2, while in the remaining 6 (28.6%), it was higher than the baseline value. At 3 months, 5 of the 15 patients with lower PTH levels up to the 3rd month experienced an increase in these levels again.
  
  
  CONCLUSIONS
  Administration of intravenous vitamin C in hemodialysis patients noticeably decreased level of PTH, but its effect gradually diminished.
authors: Division of Nephrology, Department of Internal Medicine, Zahedan University of Medical Sciences, Zahedan, Iran.
authors: Houshang
authors: H
authors: Sanadgol
authors: Mahtab
authors: M
authors: Bayani
authors: Mahdi
authors: M
authors: Mohammadi
authors: Baktash
authors: B
authors: Bayani
authors: Mohammad Ali
authors: MA
authors: Mashhadi
mesh_terms: D000328:Adult; D001205:Ascorbic Acid / Q000008:administration & dosage* / Q000493:pharmacokinetics; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000097:blood / Q000188:drug therapy* / Q000209:etiology; D007275:Injections, Intravenous; D007676:Kidney Failure, Chronic / Q000097:blood / Q000150:complications / Q000628:therapy*; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood*; D006435:Renal Dialysis; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome; D014815:Vitamins / Q000008:administration & dosage / Q000493:pharmacokinetics
chemical_list: D010281:Parathyroid Hormone; D014815:Vitamins; D001205:Ascorbic Acid