title: The Association Between Obesity and Cognitive Function in Older Persons: How Much Is Mediated by Inflammation, Fasting Plasma Glucose, and Hypertriglyceridemia?
abstract: The aim of the study was to determine how much of the association between obesity, measured by body mass index (BMI), and cognition in older persons is mediated through inflammation, fasting plasma glucose, and hypertriglyceridemia.
  
  
  
  Anthropometrics, high-sensitivity C-reactive protein (CRP), fasting plasma glucose, and serum triglycerides were measured in 3,256 community-dwelling individuals aged 55-85 years residing in Newcastle, New South Wales, Australia. Audio recorded cognitive screen (ARCS) was used to assess multiple cognitive domains.
  
  
  
  Mediation analyses showed very modest but significant direct mediation effects, whereby obesity was associated with better cognitive function after adjusting for potential confounders (controlled direct effect ≈ 1/500 point increase in the total ARCS score per 1.0-kg/m2increase in BMI). There were significant indirect negative mediation effects from BMI to cognition mediated through CRP, that is, increased BMI was associated with increased CRP which was associated with decreased cognition (natural indirect effect -0.20 unit; 95% confidence interval [CI] -0.39, -0.02), and through fasting plasma glucose, that is, increased BMI was associated with increased fasting plasma glucose which was associated with decreased cognition (natural indirect effect -0.12 unit; 95% CI -0.24, -0.01], but not through serum triglycerides.
  
  
  
  There is a weak positive association between obesity and cognitive performance in older persons, which is partially antagonized by inflammation and elevated fasting plasma glucose, but not hypertriglyceridemia. Further studies are needed to elucidate whether this is due to selection bias, or truly reflects biologically complex and counter balancing pathways involved in obesity.
authors.affiliation: Department of Geriatric Medicine and roshangun@yahoo.com.
authors.forename: Roshan
authors.initials: R
authors.lastname: Gunathilake
authors.affiliation: Hunter Medical Research Institute, John Hunter Hospital, Newcastle, New South Wales, Australia.
authors.forename: Christopher
authors.initials: C
authors.lastname: Oldmeadow
authors.affiliation: School of Medicine and Public Health.
authors.forename: Mark
authors.initials: M
authors.lastname: McEvoy
authors.affiliation: Hunter Medical Research Institute, John Hunter Hospital, Newcastle, New South Wales, Australia.|School of Nursing and Midwifery and.|Centre for Rural and Remote Mental Health, University of Newcastle, New South Wales, Australia.
authors.forename: Kerry J
authors.initials: KJ
authors.lastname: Inder
authors.affiliation: School of Medicine and Public Health.
authors.forename: Peter W
authors.initials: PW
authors.lastname: Schofield
authors.affiliation: School of Medicine and Public Health.|Department of Medicine, John Hunter Hospital, Newcastle, New South Wales, Australia.
authors.forename: Balakrishnan R
authors.initials: BR
authors.lastname: Nair
authors.affiliation: Hunter Medical Research Institute, John Hunter Hospital, Newcastle, New South Wales, Australia.|School of Medicine and Public Health.|Department of Medicine, John Hunter Hospital, Newcastle, New South Wales, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Attia
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000886:Anthropometry; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism*; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000378:metabolism; D003072:Cognition Disorders / Q000097:blood*; D005260:Female; D006801:Humans; D015228:Hypertriglyceridemia / Q000097:blood*; D007249:Inflammation / Q000097:blood; D008297:Male; D008875:Middle Aged; D009517:New South Wales; D009765:Obesity / Q000097:blood*; D012307:Risk Factors
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D002097:C-Reactive Protein
keywords: Cognition; Diabetes; Inflammation; Metabolism; Obesity