title: Effectiveness of homocysteine lowering vitamins in prevention of thrombotic tendency at high altitude area: A randomized field trial.
abstract: BACKGROUND
  A higher risk of thrombosis has been reported on prolonged stay at high altitude (HAA). Lowering of homocysteine (Hcy) has been found to reduce the risk of venous thrombosis. A randomized field trial was conducted with primary question whether Hcy lowering agents have any effect on the incidence of thrombosis at HAA amongst Indian soldiers as compared to existing interventions.
  
  
  METHODS
  All units freshly inducted to HAA were randomized into intervention (Vit B12 1000 microgram/day, B6 3mg/day & folic acid 5mg/day) and control arms, with a sample size of 12,000 person-years in each arm.
  
  
  RESULTS
  At the end of one year stay at HAA, Folate and B 12 levels decreased significantly in control arm. The levels of Hcy, fibrinogen and plasminogen activator inhibitor (PAI 1) were lower and nitric oxide higher in intervention arm as compared to control arm (p<0.05). At the end of 2years, 5 thrombotic episodes occurred in the intervention arm and 17 in control arm with RR of 0.29 (95% CI 0.11-0.80), attributable fraction % (AFe) 70.59%, Population attributable risk percent 54.55% and Protective Fraction 240%.
  
  
  CONCLUSIONS
  Intervention with B12 and folic acid is effective in reducing Hcy, PAI 1, fibrinogen levels and increasing NO levels at 1yr as compared to control arm and reducing the incidence of thrombosis at 2years of stay at HAA. Thus, vitamin B 12, B6 and folic acid intervention is safe and effective method of reducing morbidity and mortality caused by HAA induced coagulopathy.
authors: Department of Hematology, Sir Gangaram Hospital & GRIPMER, Rajinder Nagar, New Delhi, 110060, India. Electronic address: atuljyot@hotmail.com.
authors: Jyoti
authors: J
authors: Kotwal
authors: Commandant Hospital, Leh and Consultant Comm Med & Epidemiologist. Electronic address: dratulkotwal@gmail.com.
authors: Atul
authors: A
authors: Kotwal
authors: Director AFMS (Medical Research), O/o DGAFMS, New Delhi, India. Electronic address: bhallasap@gmail.com.
authors: Sandeep
authors: S
authors: Bhalla
authors: Addl DGMS (Army), O/o DGMS (Army), New Delhi, India. Electronic address: Rakhi9pk@yahoo.co.in.
authors: P K
authors: PK
authors: Singh
authors: DCIDS (Med), New Delhi, India. Electronic address: numd2012.medicine@gmail.com.
authors: Velu
authors: V
authors: Nair
mesh_terms: D000531:Altitude; D006710:Homocysteine / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D012307:Risk Factors; D013927:Thrombosis / Q000517:prevention & control*
chemical_list: D006710:Homocysteine
keywords: High Altitude; Homocysteine; PAI-1; Randomised Field Trial; Thrombosis