title: Relation between circadian patterns in levels of circulating lipoprotein(a), fibrinogen, platelets, and related lipid variables in men.
abstract: BACKGROUND
  A correlation has been reported between lipoprotein(a) [Lp(a)] concentration and risk for coronary artery disease. High concentrations of Lp(a) might be markers for vascular or tissue injury or might be associated with other genetic or environmental factors that can cause acute myocardial infarction.
  
  
  METHODS
  We measured the circadian characteristics of circulating Lp(a), fibrinogen, platelets, cholesterol, triglycerides, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol for a group of adult male volunteers who had no clinical symptoms. We obtained samples every 3 hours around the clock to assess the normal degree of variation within a 24-hour period and to test for similarities in circadian patterns and correlations with level of Lp(a).
  
  
  RESULTS
  Each variable displayed a highly significant circadian rhythm. Lp(a), fibrinogen, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol peaked in the morning. Cholesterol and platelets peaked in the late afternoon, and triglycerides peaked in the evening.
  
  
  CONCLUSIONS
  Although peak levels of Lp(a) and fibrinogen coincide with reported morning peak frequencies of myocardial infarction and stroke, the platelet peak appears to coincide with late afternoon peak frequencies of sudden cardiac death and fatal stroke. The data suggest that proper timing of single samples may improve the usefulness and accuracy of diagnosis, risk assessment, and therapy.
authors.affiliation: MacNeal Cardiology Group, Berwyn, IL 60402, USA.
authors.forename: W F
authors.initials: WF
authors.lastname: Bremner
authors.forename: R B
authors.initials: RB
authors.lastname: Sothern
authors.forename: E L
authors.initials: EL
authors.lastname: Kanabrocki
authors.forename: M
authors.initials: M
authors.lastname: Ryan
authors.forename: J B
authors.initials: JB
authors.lastname: McCormick
authors.forename: S
authors.initials: S
authors.lastname: Dawson
authors.forename: E S
authors.initials: ES
authors.lastname: Connors
authors.forename: R
authors.initials: R
authors.lastname: Rothschild
authors.forename: J L
authors.initials: JL
authors.lastname: Third
authors.forename: S
authors.initials: S
authors.lastname: Vahed
authors.forename: B M
authors.initials: BM
authors.lastname: Nemchausky
authors.forename: P
authors.initials: P
authors.lastname: Shirazi
authors.forename: J H
authors.initials: JH
authors.lastname: Olwin
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D001792:Blood Platelets / Q000502:physiology*; D008076:Cholesterol, HDL / Q000097:blood*; D008078:Cholesterol, LDL / Q000097:blood*; D002940:Circadian Rhythm; D003327:Coronary Disease / Q000097:blood*; D005340:Fibrinogen / Q000378:metabolism*; D006801:Humans; D017270:Lipoprotein(a) / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010976:Platelet Count; D011379:Prognosis; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014280:Triglycerides / Q000097:blood
chemical_list: D015415:Biomarkers; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D017270:Lipoprotein(a); D014280:Triglycerides; D005340:Fibrinogen