title: The contrasting relationships between betaine and homocysteine in two clinical cohorts are associated with plasma lipids and drug treatments.
abstract: BACKGROUND
  Urinary betaine excretion positively correlated with plasma homocysteine in outpatients attending a lipid disorders clinic (lipid clinic study). We aimed to confirm this in subjects with established vascular disease.
  
  
  METHODS
  The correlation between betaine excretion and homocysteine was compared in samples collected from subjects 4 months after hospitalization for an acute coronary episode (ACS study, 415 urine samples) and from 158 sequential patients visiting a lipid disorders clinic.
  
  
  RESULTS
  In contrast to the lipid clinic study, betaine excretion and plasma homocysteine did not correlate in the total ACS cohort. Differences between the patient groups included age, non-HDL cholesterol and medication. In ACS subjects with below median betaine excretion, excretion correlated (using log transformed data) negatively with plasma homocysteine (r = -0.17, p = 0.019, n = 199), with no correlation in the corresponding subset of the lipid clinic subjects. In ACS subjects with above median betaine excretion a positive trend (r = +0.10) between betaine excretion and homocysteine was not significant; the corresponding correlation in lipid clinic subjects was r = +0.42 (p = 0.0001). In ACS subjects, correlations were stronger when plasma non-HDL cholesterol and betaine excretion were above the median, r = +0.20 (p = 0.045); in subjects above median non-HDL cholesterol and below median betaine excretion, r = -0.26 (p = 0.012). ACS subjects taking diuretics or proton pump inhibitors had stronger correlations, negative with lower betaine excretion and positive with higher betaine excretion.
  
  
  CONCLUSIONS
  Betaine excretion correlates with homocysteine in subjects with elevated blood lipids.
authors.affiliation: Canterbury Health Laboratories, Clinical Biochemistry Unit, Christchurch, New Zealand. michael.lever@otago.ac.nz
authors.forename: Michael
authors.initials: M
authors.lastname: Lever
authors.forename: Peter M
authors.initials: PM
authors.lastname: George
authors.forename: Wendy
authors.initials: W
authors.lastname: Atkinson
authors.forename: Jane L
authors.initials: JL
authors.lastname: Elmslie
authors.forename: Sandy
authors.initials: S
authors.lastname: Slow
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Molyneux
authors.forename: Richard W
authors.initials: RW
authors.lastname: Troughton
authors.forename: A Mark
authors.initials: AM
authors.lastname: Richards
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Frampton
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Chambers
mesh_terms: D054058:Acute Coronary Syndrome / Q000097:blood* / Q000652:urine*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001622:Betaine / Q000378:metabolism* / Q000652:urine; D002784:Cholesterol / Q000097:blood; D015331:Cohort Studies; D005260:Female; D006710:Homocysteine / Q000097:blood / Q000378:metabolism*; D006760:Hospitalization; D006801:Humans; D052439:Lipid Metabolism Disorders / Q000097:blood* / Q000652:urine*; D008055:Lipids / Q000097:blood*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D015203:Reproducibility of Results; D012107:Research Design; D014652:Vascular Diseases / Q000097:blood* / Q000652:urine*
chemical_list: D008055:Lipids; D006710:Homocysteine; D001622:Betaine; D002784:Cholesterol