title: Age, waist circumference, and blood pressure are associated with skin microvascular flow motion: the Maastricht Study.
abstract: OBJECTIVE
  Skin microvascular flow motion (SMF)--blood flow fluctuation attributed to the rhythmic contraction and dilation of arterioles--is thought to be an important component of the microcirculation, by ensuring optimal delivery of nutrients and oxygen to tissue and regulating local hydraulic resistance. There is some evidence that SMF is altered in obesity, type 2 diabetes mellitus, and hypertension. Nevertheless, most studies of SMF have been conducted in highly selected patient groups, and evidence how SMF relates to other cardiovascular risk factors is scarce. Therefore, the aim of the present study was to examine in a population-based setting which cardiovascular risk factors are associated with SMF.
  
  
  METHODS
  We measured SMF in 506 participants of the Maastricht Study without prior cardiovascular event. SMF was investigated using Fourier transform analysis of skin laser Doppler flowmetry at rest within five frequency intervals in the 0.01-1.6-Hz spectral range. The associations with SMF of the cardiovascular risk factors age, sex, waist circumference, total-to-high-density lipoprotein cholesterol, fasting plasma glucose, 24-h SBP, and cigarette smoking were analysed by use of multiple linear regression analysis.
  
  
  RESULTS
  Per 1 SD higher age, waist circumference and 24-h SBP, SMF was 0.16 SD higher [95% confidence interval (CI) 0.07, 0.25; P < 0.001), -0.14 SD lower (95% CI -0.25, -0.04; P = 0.01), and 0.16 SD higher (95% CI 0.07, 0.26; P < 0.001), respectively, in fully adjusted analyses. We found no significant associations of sex, fasting plasma glucose levels, total-to-high-density lipoprotein cholesterol ratio, or pack years of smoking with SMF.
  
  
  CONCLUSIONS
  Age and 24-h SBP are directly, and waist circumference is inversely associated with SMF in the general population. The exact mechanisms underlying these findings remain elusive. We hypothesize that flow motion may be an important component of the microcirculation by ensuring optimal delivery of nutrients and oxygen to tissue and regulating local hydraulic resistance not only under physiological conditions but also under pathophysiological conditions when microcirculatory perfusion is reduced, such as occurs with ageing and higher blood pressure. In addition, obesity may result in an impaired flow motion with negative effects on the delivery of nutrients and oxygen to tissue and local hydraulic resistance.
authors.affiliation: aDepartment of Internal Medicine, Maastricht University Medical Centre (MUMC+) bCardiovascular Research Institute Maastricht (CARIM) cDepartment of Social Medicine dCAPHRI School for Public Health and Primary Care eDepartment of Epidemiology, Maastricht University, Maastricht, the Netherlands.
authors.forename: Dennis M J
authors.initials: DM
authors.lastname: Muris
authors.forename: Alfons J H M
authors.initials: AJ
authors.lastname: Houben
authors.forename: Abraham A
authors.initials: AA
authors.lastname: Kroon
authors.forename: Ronald M A
authors.initials: RM
authors.lastname: Henry
authors.forename: Carla J H
authors.initials: CJ
authors.lastname: van der Kallen
authors.forename: Simone J S
authors.initials: SJ
authors.lastname: Sep
authors.forename: Annemarie
authors.initials: A
authors.lastname: Koster
authors.forename: Pieter C
authors.initials: PC
authors.lastname: Dagnelie
authors.forename: Miranda T
authors.initials: MT
authors.lastname: Schram
authors.forename: Coen D A
authors.initials: CD
authors.lastname: Stehouwer
mesh_terms: D001794:Blood Pressure; D002318:Cardiovascular Diseases / Q000503:physiopathology*; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology; D005260:Female; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D017078:Laser-Doppler Flowmetry; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D011446:Prospective Studies; D012039:Regional Blood Flow; D012307:Risk Factors; D012867:Skin / Q000098:blood supply*; D055105:Waist Circumference