title: Impact of age and gender on microvascular function.
abstract: BACKGROUND
  Microcirculatory function can be assessed by postocclusive reactive hyperaemia (PORH) using laser Doppler fluxmetry. Previous studies have shown that PORH reveals microvascular damage at an early stage. In particular, at younger ages, PORH might depend on age and gender. To implement PORH into a larger scale of clinical studies, one has to be aware of the influence of age and gender on microcirculation. The aim of this study was to assess the impact of age and gender on microcirculatory function during adolescence.
  
  
  METHODS
  Within the scope of an epidemiological project, 896 children and adolescents underwent assessment of PORH by laser Doppler fluxmetry. Microcirculatory parameters during PORH (baseline perfusion, biological zero, peak perfusion, time to peak perfusion and recovery time) were analysed in relation to age (by tertiles) and gender.
  
  
  RESULTS
  Baseline perfusion, biological zero and peak perfusion were lower in children/adolescents in the upper age tertile (12·3-18·1 years) than in the middle (9·8-12·2 years) and lower (4·3-9·7 years) age tertiles (P < 0·0001). In the total of participants, baseline perfusion, biological zero and peak perfusion were higher in males than in females (P < 0·0001). Analysing microcirculatory parameters as a function of age and gender, the sex differences were only apparent in the upper and the middle age tertiles, but not in the lower.
  
  
  CONCLUSIONS
  During adolescence, PORH is a function of age. At higher age, microvascular reactivity considerably depends on gender, whereas no sex differences are present at younger ages.
authors.affiliation: Division of Angiology, Department of Medicine II, Medical University of Vienna, Vienna, Austria.
authors.forename: Oliver
authors.initials: O
authors.lastname: Schlager
authors.forename: Aura
authors.initials: A
authors.lastname: Giurgea
authors.forename: Alexandra
authors.initials: A
authors.lastname: Hammer
authors.forename: Silvia
authors.initials: S
authors.lastname: Charwat-Resl
authors.forename: Christian
authors.initials: C
authors.lastname: Margeta
authors.forename: Markus
authors.initials: M
authors.lastname: Mueller
authors.forename: Teresa
authors.initials: T
authors.lastname: Ehringer
authors.forename: Sonja
authors.initials: S
authors.lastname: Zehetmayer
authors.forename: Andrea
authors.initials: A
authors.lastname: Willfort-Ehringer
authors.forename: Renate
authors.initials: R
authors.lastname: Koppensteiner
authors.forename: Michael E
authors.initials: ME
authors.lastname: Gschwandtner
mesh_terms: D000293:Adolescent; D000375:Aging / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008026:Ligation; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D012727:Sex Characteristics; D012867:Skin / Q000098:blood supply
keywords: Endothelial function; epidemiology; laser Doppler; microcirculation; microvascular reactivity