title: Plasma phospholipid PUFAs are associated with greater muscle and knee extension strength but not with changes in muscle parameters in older adults.
abstract: BACKGROUND
  Muscle mass, intermuscular adipose tissue, and strength are important indicators of physical function. Dietary fatty acids (FAs) have been associated with muscle parameters such as larger size and higher strength, but large, population-based longitudinal data in older adults who are at risk of functional decline are lacking.
  
  
  OBJECTIVE
  The objective of this study was to investigate associations between plasma phospholipid polyunsaturated fatty acids (PUFAs) and measures of muscle size, intermuscular adipose tissue, and muscle strength cross-sectionally and after 5 y of follow-up.
  
  
  METHODS
  Data are from the Age, Gene/Environment Susceptibility-Reykjavik Study, a prospective cohort aged 66-96 y at baseline. The analytic sample included 836 participants with cross-sectional measures of muscle parameters and 459 participants with data on change in muscle parameters. PUFAs were assessed at study baseline through use of GC. Muscle parameters were assessed at baseline and after a median of 5.2 y. Muscle area and intermuscular adipose tissue were assessed with computed tomography. Maximal grip strength and knee extension strength were assessed with dynometers. Relative changes in muscle parameters (%) were calculated. Multivariate linear regression was performed to calculate unstandardized regression coefficients and P values for trends across tertiles of FAs are reported.
  
  
  RESULTS
  Higher concentrations of total PUFAs were cross-sectionally associated with larger muscle size (P-trend: 0.002) and with greater knee extension strength (P-trend: 0.038). Higher concentrations of arachidonic acid were associated with smaller muscle size (P-trend: 0.015). Greater linoleic acid was associated with less intermuscular adipose tissue (P-trend: 0.004), whereas eicosapentaenoic acid (20:5n-3) was positively associated (P-trend: 0.047). Longitudinal analyses showed positive associations for α-linolenic acid with increased knee extension strength (P-trend: 0.014). No other associations were observed.
  
  
  CONCLUSIONS
  These data illustrate the complex relation between plasma phospholipid PUFAs and muscle parameters; inconsistent cross-sectional relations with muscle size, intermuscular adipose tissue, and strength, and little evidence of a role in changes in muscle parameters.
authors.affiliation: Laboratory of Epidemiology and Population Sciences, National Institute on Aging, Bethesda, MD Department of Health Sciences ilse.reinders@nih.gov.
authors.forename: Ilse
authors.initials: I
authors.lastname: Reinders
authors.affiliation: Division of Public Health Sciences, Cancer Prevention Program, Fred Hutchinson Cancer Research Center, Seattle, WA.
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Song
authors.affiliation: Department of Health Sciences Department of Epidemiology and Biostatistics and the EMGO+ Institute for Health and Care Research, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Marjolein
authors.initials: M
authors.lastname: Visser
authors.affiliation: Icelandic Heart Association Research Institute, Kopavogur, Iceland; and.
authors.forename: Gudny
authors.initials: G
authors.lastname: Eiriksdottir
authors.affiliation: Icelandic Heart Association Research Institute, Kopavogur, Iceland; and Faculty of Medicine, University of Iceland, Reykjavik, Iceland.
authors.forename: Vilmundur
authors.initials: V
authors.lastname: Gudnason
authors.affiliation: Icelandic Heart Association Research Institute, Kopavogur, Iceland; and.
authors.forename: Sigurdur
authors.initials: S
authors.lastname: Sigurdsson
authors.affiliation: Icelandic Heart Association Research Institute, Kopavogur, Iceland; and Faculty of Medicine, University of Iceland, Reykjavik, Iceland.
authors.forename: Thor
authors.initials: T
authors.lastname: Aspelund
authors.affiliation: Icelandic Heart Association Research Institute, Kopavogur, Iceland; and.
authors.forename: Kristin
authors.initials: K
authors.lastname: Siggeirsdottir
authors.affiliation: Department of Health Sciences.
authors.forename: Ingeborg A
authors.initials: IA
authors.lastname: Brouwer
authors.affiliation: Laboratory of Epidemiology and Population Sciences, National Institute on Aging, Bethesda, MD.
authors.forename: Tamara B
authors.initials: TB
authors.lastname: Harris
authors.affiliation: Laboratory of Epidemiology and Population Sciences, National Institute on Aging, Bethesda, MD.
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Murphy
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology; D000368:Aged; D000369:Aged, 80 and over; D016718:Arachidonic Acid / Q000097:blood; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage; D015118:Eicosapentaenoic Acid / Q000097:blood; D005227:Fatty Acids / Q000008:administration & dosage; D005231:Fatty Acids, Unsaturated / Q000097:blood*; D005260:Female; D018737:Hand Strength; D006801:Humans; D007055:Iceland; D007717:Knee; D016014:Linear Models; D019787:Linoleic Acid / Q000097:blood; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000033:anatomy & histology*; D010743:Phospholipids / Q000097:blood*; D011446:Prospective Studies; D017962:alpha-Linolenic Acid / Q000097:blood
chemical_list: D004042:Dietary Fats, Unsaturated; D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D010743:Phospholipids; D017962:alpha-Linolenic Acid; D016718:Arachidonic Acid; D019787:Linoleic Acid; D015118:Eicosapentaenoic Acid
keywords: epidemiology; muscle loss; muscle parameters; older adults; polyunsaturated fatty acids