title: Muscle grip strength predicts incident type 2 diabetes: Population-based cohort study.
abstract: To determine the longitudinal relationship of muscle mass and strength with incident type 2 diabetes, and previously unstudied mediating effects of testosterone and inflammation.
  
  
  
  Community-dwelling male participants (aged ≥35years) of the Men Androgen Inflammation Lifestyle Environment and Stress (MAILES) Study underwent biomedical assessment in 2002-2006 and 2007-2010, including hand grip strength (dynamometer), testosterone and inflammatory markers. Body composition (dual-energy X-ray absorptiometry) was assessed at baseline only. Incident type 2 diabetes was defined as a self-reported doctor diagnosis, diabetes medication use, fasting plasma glucose ≥7.0mmol/L, or glycated haemoglobin ≥6.5% (48mmol/mol) at follow-up, that was not present at baseline.
  
  
  
  Of n=1632 men, incident type 2 diabetes occurred in 146 (8.9%). Muscle mass was not associated with incident type 2 diabetes. Grip strength was inversely associated with incident type 2 diabetes [unadjusted odds ratio (OR) per 5kg: 0.87, 95% confidence interval (CI): 0.80-0.95; adjusted OR, 95% CI: 0.87, 0.78-0.97]. Arm muscle quality (grip strength divided by arm lean mass) was similarly associated with incident type 2 diabetes. Testosterone, IL-6 and TNF-α did not significantly mediate the associations. The population attributable fraction of type 2 diabetes from low grip strength was 27% (13-40%), assuming intervention could increase strength by 25%.
  
  
  
  Reduced muscle strength, but not reduced muscle mass, is a risk factor for incident type 2 diabetes in men. This is not mediated by testosterone or inflammation. Intervention could prevent a substantial proportion of disease.
authors.affiliation: The Health Observatory, School of Medicine, University of Adelaide; Freemasons Foundation Centre for Men's Health, School of Medicine, University of Adelaide. Electronic address: joule.li@adelaide.edu.au.
authors.forename: Joule J
authors.initials: JJ
authors.lastname: Li
authors.affiliation: Freemasons Foundation Centre for Men's Health, School of Medicine, University of Adelaide.
authors.forename: Gary A
authors.initials: GA
authors.lastname: Wittert
authors.affiliation: Freemasons Foundation Centre for Men's Health, School of Medicine, University of Adelaide.
authors.forename: Andrew
authors.initials: A
authors.lastname: Vincent
authors.affiliation: School of Nursing and Midwifery, Western Sydney University.
authors.forename: Evan
authors.initials: E
authors.lastname: Atlantis
authors.affiliation: Population Research and Outcome Studies, School of Medicine, University of Adelaide.
authors.forename: Zumin
authors.initials: Z
authors.lastname: Shi
authors.affiliation: The Health Observatory, School of Medicine, University of Adelaide; Freemasons Foundation Centre for Men's Health, School of Medicine, University of Adelaide.
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Appleton
authors.affiliation: The Health Observatory, School of Medicine, University of Adelaide.
authors.forename: Catherine L
authors.initials: CL
authors.lastname: Hill
authors.affiliation: NHMRC Clinical Trials Centre, Sydney Medical School, University of Sydney.
authors.forename: Alicia J
authors.initials: AJ
authors.lastname: Jenkins
authors.affiliation: NHMRC Clinical Trials Centre, Sydney Medical School, University of Sydney.
authors.forename: Andrzej S
authors.initials: AS
authors.lastname: Januszewski
authors.affiliation: The Health Observatory, School of Medicine, University of Adelaide.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Adams
mesh_terms: D000328:Adult; D000368:Aged; D001823:Body Composition / Q000502:physiology; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D015994:Incidence; D008019:Life Style; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000503:physiopathology; D012307:Risk Factors; D013739:Testosterone / Q000097:blood
chemical_list: D013739:Testosterone
keywords: Dual energy X-ray absorptiometry; Grip strength; Lean mass; Muscle strength; Skeletal muscle