title: Sex differences in the association of fasting and postchallenge glucose levels with grip strength among older adults: the Rancho Bernardo Study.
abstract: OBJECTIVE
  Persons with diabetes have accelerated muscle loss. The association of fasting and postchallenge glucose levels per se to grip strength, a clinical marker of poor physical function, and potential sex differences in this relationship has not been previously described.
  
  
  METHODS
  Longitudinal cohort.
  
  
  METHODS
  USA.
  
  
  METHODS
  Participants were community-dwelling older adults (mean age 71.3 years) without self-reported diabetes and/or use of diabetes medication with glucose measured at baseline (1992-1996).
  
  
  METHODS
  Fasting plasma glucose (FPG) was measured in 1019 women and 636 men. Two-hour glucose (2HG) levels after a 75 g oral glucose tolerance test were also available (women, n=870; men, n=559). Dominant hand grip strength was assessed using a hand-held dynamometer at 3.0±1.6 visits over a median 7.0 years. Mixed linear models examined the association of baseline glucose levels with grip strength, accounting for repeated visits, and adjusting for covariates.
  
  
  RESULTS
  Sex-specific FPG quartiles were associated with unadjusted differences in grip strength among women (p=0.03) but not men (p=0.50). However, in men, adjusting for age, education, height, weight, peripheral neuropathy, physical activity, and comorbidities, each SD (SD=17 mg/dL) higher FPG was associated with persistently lower grip strength (-0.44±0.22 kg, p=0.049); 2HG (SD=50 mg/dL) was unrelated to grip strength (-0.39±0.25 kg, p=0.13). In women, neither FPG (SD=16 mg/dL) nor 2HG (SD=45 mg/dL) was associated with grip strength (0.02±0.12 kg, p=0.90; and -0.20±0.14 kg, p=0.14; respectively) after adjustment. The rate of change in grip strength did not differ across FPG or 2HG quartiles in either sex.
  
  
  CONCLUSIONS
  In age-adjusted analyses, elevated fasting glucose levels are associated with persistently lower grip strength in older men, but not women. Future studies are needed to elucidate reasons for these sex differences and may provide further insight into accelerated loss of muscle function as a complication of diabetes in older adults.
authors.affiliation: Division of Endocrinology, Diabetes & Metabolism, Department of Medicine , The Johns Hopkins University , Baltimore, Maryland , USA.
authors.forename: Rita Rastogi
authors.initials: RR
authors.lastname: Kalyani
authors.affiliation: University of Michigan , Ann Arbor, Michigan , USA.
authors.forename: Catherine
authors.initials: C
authors.lastname: Kim
authors.affiliation: Clinical Research Branch, National Institute on Aging , Baltimore, Maryland , USA.
authors.forename: Luigi
authors.initials: L
authors.lastname: Ferrucci
authors.affiliation: Division of Epidemiology, Department of Family and Preventive Medicine , University of California, San Diego , La Jolla, California , USA.
authors.forename: Gail A
authors.initials: GA
authors.lastname: Laughlin
authors.affiliation: Division of Epidemiology, Department of Family and Preventive Medicine , University of California, San Diego , La Jolla, California , USA.
authors.forename: Donna
authors.initials: D
authors.lastname: Kritz-Silverstein
authors.affiliation: Purdue University , West Lafayette, Indiana , USA.
authors.forename: Shengchun
authors.initials: S
authors.lastname: Kong
authors.affiliation: University of Michigan , Ann Arbor, Michigan , USA.
authors.forename: Bin
authors.initials: B
authors.lastname: Nan
authors.affiliation: Division of Epidemiology, Department of Family and Preventive Medicine , University of California, San Diego , La Jolla, California , USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Barrett-Connor
keywords: Elderly; Epidemiology; Muscle Weakness; Sex Difference