Diminishing motor function is commonly observed in the elderly population and is associated with a wide range of adverse health consequences. Advanced Glycation End products (AGE’s) may contribute to age-related decline in the function of cells and tissues in normal ageing. Although the negative effect of AGE’s on the biomechanical properties of musculoskeletal tissues and the central nervous system have been previously described, the evidence regarding the effect on motor function is fragmented, and a systematic review on this topic is lacking. Therefore, a systematic review was conducted from a total of eight studies describing AGE’s related to physical functioning, physical performance, and musculoskeletal outcome which reveals a positive association between high AGE’s levels and declined walking abilities, inferior ADL, decreased muscle properties (strength, power and mass) and increased physical frailty. Elevated AGE’s levels might be an indication to initiate (early) treatment such as dietary advice, muscle strengthening exercises, and functional training to maintain physical functions. Further longitudinal observational and controlled trial studies are necessary to investigate a causal relationship, and to what extent, high AGE’s levels are a contributing risk factor and potential biomarker for a decline in motor function as a component of ageing process.
Paratonia, a distinctive form of hypertonia in patients with dementia, causes loss of functional mobility in early stage dementia to severe contractures and pain in the late stages. The pathogenesis of paratonia is not well understood. Patients in early stage dementia with diabetes mellitus showed a significantly higher risk for the development of paratonia. Both Alzheimer disease and diabetes mellitus are related to higher concentrations of advanced glycation end-products (AGEs). The purpose of this study is to explore the association of AGEs with the prevalence and severity of paratonia in patients with Alzheimer disease.DESIGN: Observational longitudinal, 1-year follow-up cohort study with 3 assessments.SETTING: Day care centers for patients with dementia.PARTICIPANTS: A total of 144 community-dwelling patients with early stage Alzheimer or Alzheimer/vascular disease were recruited from 24 dementia day care centers in The Netherlands.MEASUREMENTS: The presence of paratonia (Paratonia Assessment Instrument), the severity of paratonia (Modified Ashworth Scale for paratonia), and AGE levels (AGE-reader).RESULTS: From the 144 participants (56.3% female and 43.7% male, with a mean [standard deviation] age of 80.7 [7.7] years), 118 participants were available for final follow-up. A significant association between AGE levels and the presence of paratonia (odds ratio 3.47, 95% confidence interval [CI] 1.87-6.44, P < .001) and paratonia severity (β = 0.17, 95% CI 0.11-0.23, P < .001) was determined. In participants who developed paratonia and those with persistent paratonia throughout the study the AGE levels (95% CI -0.38 to -0.13, P < .001 and 95% CI -0.46 to -0.06, P = .012, respectively) and the severity of paratonia (95% CI -0.60 to -0.35, P < .001 and 95% CI -0.38 to -0.12, P < .001, respectively) significantly increased, whereas the AGE levels remained stable in those participants without paratonia. Notwithstanding, change in AGE levels was not significantly (P = .062) related to change in paratonia severity, mixed model analyses provided evidence for both a significant time and between participant effect of AGEs on paratonia severity.CONCLUSIONS: This study suggests that elevated AGE levels are a contributing factor to paratonia and its severity and could be the result of peripheral biomechanical changes reducing elasticity and increasing stiffness. These results provide a new perspective on paratonia and gives rise to further research whether paratonia could be postponed or movement stiffness can be improved by reducing AGE levels.
