title: Declines in Strength and Mortality Risk Among Older Mexican Americans: Joint Modeling of Survival and Longitudinal Data.
abstract: Grip strength is a noninvasive method of risk stratification; however, the association between changes in strength and mortality is unknown. The purposes of this study were to examine the association between grip strength and mortality among older Mexican Americans and to determine the ability of changes in strength to predict mortality.
  
  
  
  Longitudinal data were included from 3,050 participants in the Hispanic Established Population for the Epidemiological Study of the Elderly. Strength was assessed using a hand-held dynamometer and normalized to body mass. Conditional inference tree analyses were used to identify sex- and age-specific weakness thresholds, and the Kaplan-Meier estimator was used to determine survival estimates across various strata. We also evaluated survival with traditional Cox proportional hazard regression for baseline strength, as well as with joint modeling of survival and longitudinal strength change trajectories.
  
  
  
  Survival estimates were lower among women who were weak at baseline for only 65- to 74-year-olds (11.93 vs 16.69 years). Survival estimates were also lower among men who were weak at baseline for only ≥75-year-olds (5.80 vs 7.39 years). Lower strength at baseline (per 0.1 decrement) was significantly associated with mortality (hazard ratio [HR]: 1.10; 95% confidence interval [CI]: 1.01-1.19) for women only. There was a strong independent, longitudinal association between strength decline and early mortality, such that each 0.10 decrease in strength, within participants over time, resulted in a HR of 1.12 (95% CI: 1.00-1.25) for women and a HR of 1.15 (95% CI: 1.04-1.28) for men.
  
  
  
  Longitudinal declines in strength are significantly associated with all-cause mortality in older Mexican Americans.
authors.affiliation: Department of Physical Medicine and Rehabilitation, mdpeterz@med.umich.edu.
authors.forename: Mark D
authors.initials: MD
authors.lastname: Peterson
authors.affiliation: Department of Surgery, and.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.affiliation: School of Public Health, Department of Epidemiology, University of Michigan, Ann Arbor.
authors.forename: Kate A
authors.initials: KA
authors.lastname: Duchowny
authors.affiliation: Department of Preventive Medicine and Community Health and.
authors.forename: Kyriakos S
authors.initials: KS
authors.lastname: Markides
authors.affiliation: Division of Rehabilitation Sciences/School of Health Professions, Department of Internal Medicine/Division of Geriatrics, Sealy Center on Aging, University of Texas Medical Branch, Galveston.
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Ottenbacher
authors.affiliation: Division of Rehabilitation Sciences/School of Health Professions, Department of Internal Medicine/Division of Geriatrics, Sealy Center on Aging, University of Texas Medical Branch, Galveston.
authors.forename: Soham Al
authors.initials: SA
authors.lastname: Snih
mesh_terms: D000368:Aged; D001247:Asthenia / Q000453:epidemiology; D004185:Disability Evaluation; D005260:Female; D015577:Geriatric Assessment; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D017058:Mexican Americans; D009026:Mortality / Q000639:trends*; D018570:Risk Assessment; D012307:Risk Factors; D016019:Survival Analysis; D014481:United States / Q000453:epidemiology
keywords: Diabetes; Handgrip; Mexican American; Mortality; Strength