Pathways from physical frailty to activity limitation in older people: Identifying moderators and mediators in the English Longitudinal Study of Ageing

Abstract

Physical frailty increases the risk of future activity limitation, which in turn, compromises independent living of older people and limits their healthspan. Thus, we seek to identify moderators and mediators of the effect of physical frailty on activity limitation change in older people, including gender- and age-specific effects. In a longitudinal study using data from waves 2, 4, and 6 of the English Longitudinal Study of Ageing, unique physical frailty factor scores of 4638 respondents aged 65 to 89years are obtained from confirmatory factor analysis of physical frailty, which is specified by three indicators, namely slowness, weakness, and exhaustion. Using a series of autoregressive cross-lagged models, we estimate the effect of physical frailty factor score on activity limitation change, including its moderation by social conditions, and indirect effects through physical and psychological conditions. We find that the effect of physical frailty on activity limitation change is significantly stronger with older age, while it has significant indirect effects through low physical activity, depressive symptoms, and cognitive impairment. In turn, indirect effects of physical frailty through low physical activity and cognitive impairment are stronger with older age. Sensitivity analyses suggest that these effects vary in their robustness to unmeasured confounding. We conclude that low physical activity, depressive symptoms, and cognitive impairment are potentially modifiable mediators on pathways from physical frailty to activity limitation in older people, including those who are very old. This evidence offers support for population-level interventions that target these conditions, to mitigate the effect of physical frailty on activity limitation, and thereby enhance healthspan.

Dietary Factors Associated with Frailty in Old Adults: A Review of Nutritional Interventions to Prevent Frailty Development

“…Another problem with frailty syndrome derives from the term itself. Frequently, the term frailty is clinically used as either age-related comorbidity or disability, but these are not synonyms; in fact, comorbidity should be a step backward from frailty and dependence should be a step forward [4,5,6]. Finally, other trouble areas are that frailty develops in a continuum from previous stages and is characterised by clinically healthy subjects who have less strength to face external stressors before reaching the final stages in which older subjects have a very diminished functional capacity [7].…”

Clinical validation of nursing diagnosis Fragile Elderly Syndrome

“…Generally, activity limitation is assessed in terms of the need for assistance in basic, instrumental, and advanced activities of daily living (ADLs, IADL, and BADL, respectively). The indicators of the scales that measure the performance of the elderly person in the performance of the ADL assess the most complex acts of daily life, which are impaired early in the incapacity, while the indicators related to the IADL and BADL measure the most basic actions such as bathing, dressing, going to the bathroom, body transfer, food and walk (17) . This is because the attributes of the frail syndrome, such as the variables contained in its phenotype, are also part of the genesis of functional disability (18) .…”

Mechanism of Synaptic Dysfunction and How This Disruption in IGF-1 homeostasis Leads to Neurodegenerative Diseases: A Theory

“…Weakness often causes a multidimensional loss of an individual's body system reserves, resulting in vulnerability to developing sequential health-related outcomes. Some clinically reported indirect effects of fragility, due to the constraint of low physical activity, have presented as depressive symptoms and cognitive impairment, both consistent with the neurological symptoms of delirium [46]. Gupta et al [45] state that a common neurological pathway may be responsible for specific 'core symptoms' of delirium (disorientation, cognitive deficits, sleep-wake cycle disturbance, disorganized thinking, and language abnormalities).…”