title: Relationship of levels of Vitamin D with flow-mediated dilatation of brachial artery in patients of myocardial infarction and healthy control: A case-control study.
abstract: BACKGROUND
  Cardiovascular diseases (CVD) remain the leading cause of death worldwide. Vitamin D deficiency has been linked to increased risk of adverse CV events. Vitamin D deficiency may be responsible for endothelial dysfunction which in turn affects the onset and progression of coronary artery disease and its risk factors, directly or indirectly through various mechanisms.
  
  
  METHODS
  It was case-control study. A total of 50 cases of acute myocardial infarction (AMI) (aged 40-60 years), admitted to medicine emergency/CCU, were taken as per ACC/AHA 2007 guidelines. An equal number of age- and sex-matched controls were also taken. Risk factors of AMI, flow-mediated dilatation (FMD), and 25(OH)D levels were studied in all cases and controls. Correlation was also studied between FMD and 25(OH)D.
  
  
  RESULTS
  The mean values of FMD were 18.86 ± 5.39% and 10.35 ± 4.90% in controls and cases, respectively (P< 0.05). The endothelial dilatation after glyceryl trinitrate (GTN) was also studied and was found to be 26.175 ± 4.25% and 18.80 ± 5.72% in controls and cases, respectively (P< 0.05). The mean levels of 25(OH)D in controls and cases were 25.45 ± 12.17 and 14.53 ± 8.28 ng/ml, respectively. In this study, 56% of subjects were Vitamin D deficient, 25% were Vitamin D insufficient, and only 19% had Vitamin D in normal range. A positive correlation coefficient was found between FMD and 25(OH) Vitamin D levels (r= 0.841,P< 0.01). In this study, a positive correlation coefficient was also found between endothelial dilatation after GTN and 25(OH)D levels (r= 0.743,P< 0.01).
  
  
  CONCLUSIONS
  In this study, it was found that FMD was markedly impaired in patients of AMI when compared to controls. It was also found that majority of the study population was Vitamin D deficient; however, the deficiency was more severe in patients of AMI. We also found out that FMD was positively correlated (r= 0.841) to the deficiency state of Vitamin D in all the study subjects.
authors.affiliation: Postgraduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Sarthak
authors.initials: S
authors.lastname: Malik
authors.affiliation: Department of Medicine, University College of Medical Sciences, New Delhi, India.
authors.forename: Subhash
authors.initials: S
authors.lastname: Giri
authors.affiliation: Department of Medicine, University College of Medical Sciences, New Delhi, India.
authors.forename: S V
authors.initials: SV
authors.lastname: Madhu
authors.affiliation: Department of Radio-diagnostic, University College of Medical Sciences, New Delhi, India.
authors.forename: Vinita
authors.initials: V
authors.lastname: Rathi
authors.affiliation: Department of Biochemistry, University College of Medical Sciences, New Delhi, India.
authors.forename: B D
authors.initials: BD
authors.lastname: Banerjee
authors.affiliation: Department of Clinical Immunology and Rheumatology, Christian Medical College, Vellore, Tamil Nadu, India.
authors.forename: Nikhil
authors.initials: N
authors.lastname: Gupta
keywords: Brachial artery; Vitamin D; case–control; flow-mediated dilatation; myocardial infarction