Poor Lower Extremity Functioning Is Associated with Modest Increased Incidence of Probable Dementia

Abstract

Lower extremity functioning in older adults provides a measure of poor physical performance and can predict negative health outcomes. The consequences of reduced lower extremity functioning on cognitive decline, measured as time-varying variables, have not been well documented in previous studies. We aimed to evaluate whether lower extremity functioning is associated with an increased incidence rate of probable dementia among older adults using data from the National Health and Aging Trends Study (NHATS). Participants (n = 6457) were followed for 8 years to examine the relationship between lower extremity functioning, as measured by the Short Physical Performance Battery (SPPB), and incident probable dementia. Using weighted data, a multivariable Poisson regression with generalized estimating equations (GEE) was used to calculate incidence rate ratios (IRR), adjusting for covariates and clustering. Participants with low SPPB scores (0–5) had a 5% increase in incident probable dementia when compared with those who had good SPPB scores (10–12) in the adjusted model (IRR = 1.05; 95% CI = 1.04–1.07). Lower extremity functioning is associated with a modest increase in incident probable dementia. The SPPB score may be helpful in identifying subjects at risk of dementia. Efforts aimed at improving physical functioning may lead to better cognitive outcomes.

Objective measures of physical function and their association with cognitive impairment in older adults with cancer prior to treatment

“…Therefore, this may explain why low SPPB but not low grip strength was associated with impaired cognition in patients with moderate-to-high comorbidity. Our findings support previous work by Teruya et al, who found that poor SPPB (defined as ≤5/12 points) was associated with a modestly increased risk of probable dementia in older adults [11].…”

“…Our findings agree with this notion given that 42.2% of older adults had poor cognitive function prior to treatment, supporting the hypothesis that older patients may be more vulnerable to cognitive change following a diagnosis of cancer. Studies in older non-cancer populations suggest an inverse association between objective measures of physical function and cognitive impairment [9][10][11][12]. Previous work in oncology has demonstrated that grip strength was associated with aspects of cognition in older cancer survivors regardless of treatment status [38].…”

“…For example, evidence in non-cancer populations has demonstrated that muscle strength measured by grip strength [9,10] and physical performance assessed via the Short Physical Performance Battery (SPPB) [11,12] are associated with cognitive function. However, in oncology, and more specifically in older adults with cancer prior to treatment, whether muscle strength and physical performance are associated with cognitive function is poorly understood for the following reasons.…”

The Value of Handgrip Strength and Self-Rated Squat Ability in Predicting Mild Cognitive Impairment: Development and Validation of a Prediction Model

“… 11 As accumulating evidence has shown the significance of lower limb function in the process of cognitive decline, a combined handgrip strength and squat ability modeling strategy might be a better solution for the prediction of MCI. 12 - 17 …”

“…11 As accumulating evidence has shown the significance of lower limb function in the process of cognitive decline, a combined handgrip strength and squat ability modeling strategy might be a better solution for the prediction of MCI. [12][13][14][15][16][17] Due to the potential benefits of using both upper and lower limb function to construct predictive models for the early identification of MCI, the objective of the current study was to establish an early MCI identification tool by combining a set of indicators, including upper limb function (handgrip strength) and lower limb function (squat ability), via a clinical prediction modeling strategy. As it has been widely accepted that early identification and early intervention is the major way to combat the spread of AD, the tool developed in the current study is expected to assist health workers in the early identification of MCI, thus allowing at-risk individuals to receive interventions as early as possible, thereby reducing the risk of AD.…”