title: Association of circulating irisin and cardiopulmonary exercise capacity in healthy volunteers: results of the Study of Health in Pomerania.
abstract: BACKGROUND
  Irisin, a recently discovered myokine, is assumed to be secreted by muscle cells in response to exercise and is involved in the regulation of energy metabolism by browning white adipose tissue cells. However, due to the fact that previous studies revealed conflicting results concerning the association between irisin and exercise, the aim of the present study was to investigate the potential relationship between irisin and exercise capacity in a population-based setting.
  
  
  METHODS
  From the population-based Study of Health in Pomerania (SHIP-TREND) 334 men and 406 women with irisin measurements were selected and a standardised symptom limited cardiopulmonary exercise test was used. Exercise capacity was quantified by oxygen uptake at anaerobic threshold (VO2@AT), peak exercise (peakVO2) and maximum power output at peak exertion. In addition, the oxygen pulse was assessed. ANOVA and multivariable linear regression analyses were performed stratified by sex and adjusted for age, weight, height and smoking.
  
  
  RESULTS
  In men, we observed inverse associations between irisin serum concentration and exercise capacity assessed by peakVO2 and maximum power output. In contrast, in women a trend towards a positive relationship between irisin and peakVO2 was detected, whereas none of the other parameters showed significant associations with irisin.
  
  
  CONCLUSIONS
  Based on a large population sample, our results did not confirm the previous reported positive linkage between exercise and irisin. Thus the relationship needs further investigation in particular with respect to sex differences.
authors.affiliation: Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße, 17475, Greifswald, Germany. nils.kerstholt@web.de.
authors.forename: Nils
authors.initials: N
authors.lastname: Kerstholt
authors.affiliation: Department of Internal Medicine B - Cardiology, Intensive Care, Pulmonary Medicine and Infectious Diseases, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße, 17475, Greifswald, Germany. ewert@uni-greifswald.de.
authors.forename: Ralf
authors.initials: R
authors.lastname: Ewert
authors.affiliation: Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße, 17475, Greifswald, Germany. matthias.nauck@uni-greifswald.de.|DZHK (German Centre for Cardiovascular Research), Greifswald partner site, Greifswald, Germany. matthias.nauck@uni-greifswald.de.
authors.forename: Matthias
authors.initials: M
authors.lastname: Nauck
authors.affiliation: Department of Internal Medicine B - Cardiology, Intensive Care, Pulmonary Medicine and Infectious Diseases, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße, 17475, Greifswald, Germany. t.spielhagen@krankenhaus-grimmen.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Spielhagen
authors.affiliation: Department of Internal Medicine B - Cardiology, Intensive Care, Pulmonary Medicine and Infectious Diseases, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße, 17475, Greifswald, Germany. bollmann@uni-greifswald.de.
authors.forename: Tom
authors.initials: T
authors.lastname: Bollmann
authors.affiliation: Department of Internal Medicine B - Cardiology, Intensive Care, Pulmonary Medicine and Infectious Diseases, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße, 17475, Greifswald, Germany. kochb@uni-greifswald.de.
authors.forename: Beate
authors.initials: B
authors.lastname: Stubbe
authors.affiliation: Department of Internal Medicine B - Cardiology, Intensive Care, Pulmonary Medicine and Infectious Diseases, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße, 17475, Greifswald, Germany. felix@uni-greifswald.de.|DZHK (German Centre for Cardiovascular Research), Greifswald partner site, Greifswald, Germany. felix@uni-greifswald.de.
authors.forename: Stephan B
authors.initials: SB
authors.lastname: Felix
authors.affiliation: Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße, 17475, Greifswald, Germany. henri.wallaschofski@hotmail.com.
authors.forename: Henri
authors.initials: H
authors.lastname: Wallaschofski
authors.affiliation: Department of Internal Medicine B - Cardiology, Intensive Care, Pulmonary Medicine and Infectious Diseases, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße, 17475, Greifswald, Germany. sven.glaeser@uni-greifswald.de.
authors.forename: Sven
authors.initials: S
authors.lastname: Gläser
authors.affiliation: Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Ferdinand-Sauerbruch-Straße, 17475, Greifswald, Germany. nele.friedrich@uni-greifswald.de.|DZHK (German Centre for Cardiovascular Research), Greifswald partner site, Greifswald, Germany. nele.friedrich@uni-greifswald.de.
authors.forename: Nele
authors.initials: N
authors.lastname: Friedrich
mesh_terms: D000328:Adult; D000368:Aged; D015308:Anaerobic Threshold; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D005353:Fibronectins / Q000097:blood*; D005858:Germany; D064368:Healthy Volunteers; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010101:Oxygen Consumption; D012737:Sex Factors
chemical_list: C577593:FNDC5 protein, human; D005353:Fibronectins