Physical Performance, body composition and disability in older adults from different epidemiologic contexts: Results from the International Mobility in Aging Study (IMIAS)
Sarcopenia; Muscle strength; Abdominal obesity; Aging; Epidemiology.
Introduction: Aging is characterized by a gradual and long-term accumulation of molecular and cellular damage that results in progressive and widespread impairment in many body functions. Among the most clinically significant changes are the muscular strength and mass (defined as sarcopenia) and increase in body adiposity that are related to the greater risk of disabilities, leading to the loss of the i functional independence. The IMIAS study aimed to analyze the difference in mobility and associated factors in older adults from different social, economic and cultural contexts. Therefore, it offers a great opportunity to examine aspects related to the aging of the musculoskeletal system, as well as factors related to functional disability in older populations that differ widely. Objectives: a) To estimate the ability of handgrip strength cut points to identify slowness in different populations of older adults; b) To identify which physical performance measures proposed for Sarcopenia screening could predict most the muscle mass in community dwelling older adults after 4 years of follow up; c) to explore the longitudinal relationship between abdominal obesity with mobility and mobility-related ADL disability controlling for physical performance and depression in older adults free from disability. Methods: This is an analytical, observational longitudinal study, where 2002 older adults were followed for 4 years of follow-up. Baseline data were collected in the year 2012. New evaluations occurred with the interval of 2 years between them, in the years 2014 and 2016. The measures of physical performance were handgrip strength and gait speed. The muscle mass was measured by of the bio impedance analysis. Functional disability measures were self-reported difficulties in tasks related to mobility and daily living activities related to mobility; the measure of obesity was defined by waist circumference. Results: The handgrip strength cut-off points of <26 kg for men and <16 kg for women were able to identify slowness in walking speed in older adults participants of the IMIAS. In addition, handgrip strength measured at baseline was significantly related to muscle mass measured 4 years later (β= 0.003, p-value <0.05). Finally, the presence of abdominal obesity, was a risk factor for disability in mobility (OR = 1.47, 95% CI 1.01-2.15) after 4 years of follow-up, however was not associated with the risk of the onset of ADL disability (OR: 1.40, 95% CI 0.90-2.18). Conclusions: The proposed cutoff points for handgrip strength can be designed to be a useful tool to screening the older adults at risk of functional problems. Further, handgrip strength can be used as a simple method for screening sarcopenia in the community dwelling older adults. Finally, the presence of abdominal obesity is associated longitudinally and predicts the risk of disability in mobility, even over a short period of time (4 years) in community dwelling older adults from different epidemiological contexts.