title: Short-term effects of air temperature on plasma metabolite concentrations in patients undergoing cardiac catheterization.
abstract: BACKGROUND
  Epidemiological studies have shown associations between air temperature and cardiovascular health outcomes. Metabolic dysregulation might also play a role in the development of cardiovascular disease.
  
  
  OBJECTIVE
  To investigate short-term temperature effects on metabolites related to cardiovascular disease.
  
  
  METHODS
  Concentrations of 45 acylcarnitines, 15 amino acids, ketone bodies and total free fatty acids were available in 2869 participants from the CATHeterization GENetics cohort recruited at the Duke University Cardiac Catheterization Clinic (Durham, NC) between 2001 and 2007. Ten metabolites were selected based on quality criteria and cluster analysis. Daily averages of meteorological variables were obtained from the North American Regional Reanalysis project. Immediate, lagged, and cumulative temperature effects on metabolite concentrations were analyzed using (piecewise) linear regression models.
  
  
  RESULTS
  Linear temperature effects were found for glycine, C16-OH:C14:1-DC, and aspartic acid/asparagine. A 5°C increase in temperature was associated with a 1.8% [95%-confidence interval: 0.3%; 3.3%] increase in glycine (5-day average), a 3.2% [0.1%; 6.3%] increase in C16-OH:C14:1-DC (lag of four days), and a -1.4% [-2.4%; -0.3%] decrease in aspartic acid/asparagine (lag of two days). Non-linear temperature effects were observed for alanine and total ketone bodies with breakpoint of 4°C and 20°C, respectively. Both a 5°C decrease in temperature on colder days (<4°C)and a 5°C increase in temperature on warmer days (≥4°C) were associated with a four day delayed increase in alanine by 6.6% [11.7; 1.8%] and 1.9% [0.3%; 3.4%], respectively. For ketone bodies we found immediate (0-day lag) increases of 4.2% [-0.5%; 9.1%] and 12.3% [0.1%; 26.0%] associated with 5°C decreases on colder (<20°C) days and 5°C increases on warmer days (≥20°C), respectively.
  
  
  CONCLUSIONS
  We observed multiple effects of air temperature on metabolites several of which are reported to be involved in cardiovascular disease. Our findings might help to understand the link between air temperature and cardiovascular disease.
authors: Institute of Epidemiology II, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstädter Landstraße 1, 85764 Neuherberg, Germany. Electronic address: regina.hampel@helmholtz-muenchen.de.
authors: Regina
authors: R
authors: Hampel
authors: Institute of Epidemiology II, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstädter Landstraße 1, 85764 Neuherberg, Germany.
authors: Susanne
authors: S
authors: Breitner
authors: School of Medicine, Duke University, Durham, NC 27701, USA.
authors: William E
authors: WE
authors: Kraus
authors: School of Medicine, Duke University, Durham, NC 27701, USA; Duke Molecular Physiology Institute, 300 North Duke Street, Durham, NC 27701, USA; Cooperative Studies Program Epidemiology Center-Durham, Veterans Affairs Medical Center, Durham, NC 27701, USA.
authors: Elizabeth
authors: E
authors: Hauser
authors: School of Medicine, Duke University, Durham, NC 27701, USA.
authors: Svati
authors: S
authors: Shah
authors: Institute of Epidemiology II, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstädter Landstraße 1, 85764 Neuherberg, Germany.
authors: Cavin K
authors: CK
authors: Ward-Caviness
authors: National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, 109 T.W. Alexander Drive, Durham, NC 27709, USA.
authors: Robert
authors: R
authors: Devlin
authors: National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, 109 T.W. Alexander Drive, Durham, NC 27709, USA.
authors: David
authors: D
authors: Diaz-Sanchez
authors: National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, 109 T.W. Alexander Drive, Durham, NC 27709, USA.
authors: Lucas
authors: L
authors: Neas
authors: National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, 109 T.W. Alexander Drive, Durham, NC 27709, USA.
authors: Wayne
authors: W
authors: Cascio
authors: Institute of Epidemiology II, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstädter Landstraße 1, 85764 Neuherberg, Germany.
authors: Annette
authors: A
authors: Peters
authors: Institute of Epidemiology II, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Ingolstädter Landstraße 1, 85764 Neuherberg, Germany.
authors: Alexandra
authors: A
authors: Schneider
mesh_terms: D000368:Aged; D000397:Air Pollution; D015415:Biomarkers / Q000097:blood; D001769:Blood / Q000378:metabolism*; D006328:Cardiac Catheterization; D002318:Cardiovascular Diseases / Q000097:blood; D016000:Cluster Analysis; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013696:Temperature; D014887:Weather
chemical_list: D015415:Biomarkers
keywords: Air temperature; Cardiovascular disease; Epidemiology; Metabolites