title: Association of digital vascular function with cardiovascular risk factors: a population study.
abstract: OBJECTIVE
  Vasodilation of the peripheral arteries during reactive hyperaemia depends in part on release of nitric oxide from endothelial cells. Previous studies mainly employed a fingertip tonometric device to derive pulse wave amplitude (PWA) and PWA hyperaemic changes. An alternative approach is based on photoplethysmography (PPG). We sought to evaluate the correlates of digital PPG PWA hyperaemic responses as a measure of peripheral vascular function.
  
  
  METHODS
  The Flemish Study on Environment, Genes and Health Outcomes (FLEMENGHO) is a population-based cohort study.
  
  
  METHODS
  Respondents were examined at one centre in northern Belgium.
  
  
  METHODS
  For this analysis, our sample consisted of 311 former participants (53.5% women; mean age 52.6 years; 43.1% hypertensive), who were examined from January 2010 until March 2012 (response rate 85.1%).
  
  
  METHODS
  Using a fingertip PPG device, we measured digital PWA at baseline and at 30 s intervals for 4 min during reactive hyperaemia induced by a 5 min forearm cuff occlusion. We performed stepwise regression to identify correlates of the hyperaemic response ratio for each 30 s interval after cuff deflation.
  
  
  RESULTS
  The maximal hyperaemic response was detected in the 30-60 s interval. The explained variance for the PPG PWA ratio ranged from 9.7% at 0-30 s interval to 22.5% at 60-90 s time interval. The hyperaemic response at each 30 s interval was significantly higher in women compared with men (p≤0.001). The PPG PWA changes at 0-90 s intervals decreased with current smoking (p≤0.0007) and at 0-240 s intervals decreased with higher body mass index (p≤0.035). These associations with sex, current smoking and body mass index were mutually independent.
  
  
  CONCLUSIONS
  Our study is the first to implement the new PPG technique to measure digital PWA hyperaemic changes in a general population. Hyperaemic response, as measured by PPG, is inversely associated with traditional cardiovascular risk factors such as male sex, smoking and obesity.
authors.affiliation: Research Unit Hypertension and Cardiovascular Epidemiology, KU Leuven Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Kuznetsova
authors.forename: Eline
authors.initials: E
authors.lastname: Van Vlierberghe
authors.forename: Judita
authors.initials: J
authors.lastname: Knez
authors.forename: Gregory
authors.initials: G
authors.lastname: Szczesny
authors.forename: Lutgarde
authors.initials: L
authors.lastname: Thijs
authors.forename: Dominique
authors.initials: D
authors.lastname: Jozeau
authors.forename: Costantino
authors.initials: C
authors.lastname: Balestra
authors.forename: Jan
authors.initials: J
authors.lastname: D'hooge
authors.forename: Jan A
authors.initials: JA
authors.lastname: Staessen
mesh_terms: D000328:Adult; D000368:Aged; D001158:Arteries / Q000502:physiology / Q000503:physiopathology; D001530:Belgium; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000209:etiology* / Q000503:physiopathology; D015331:Cohort Studies; D004730:Endothelium, Vascular / Q000502:physiology / Q000503:physiopathology*; D005260:Female; D005385:Fingers / Q000098:blood supply / Q000502:physiology; D006339:Heart Rate; D006801:Humans; D006940:Hyperemia / Q000503:physiopathology*; D006973:Hypertension / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D050177:Overweight / Q000150:complications / Q000503:physiopathology; D017156:Photoplethysmography / Q000379:methods; D011674:Pulse; D063177:Pulse Wave Analysis; D012307:Risk Factors; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects / Q000503:physiopathology*; D014664:Vasodilation
keywords: endothelial function; photoplethysmography; population; vasodilation