The Association between Poor Diet Quality, Physical Fatigability and Physical Function in the Oldest-Old from the Geisinger Rural Aging Study

Brett Davis,Gordon L Jensen,Nancy W Glynn,Xiang Gao,Brian A Irving,James Stampley,G Craig Wood,Yi-Hsuan Liu,Diane C Mitchell,Christopher D Still

doi:10.3390/geriatrics6020041

Abstract

More perceived physical fatigability and poor diet quality are associated with impairments in physical function in older adults. However, the degree to which more perceived fatigability explains the association between poor diet quality and low physical function is unknown. We examined this relationship in 122 (66F, 56M) of the oldest-old participants from the Geisinger Rural Aging Study (GRAS). We used 24-h dietary recalls to assess the Healthy Eating Index (HEI), the Pittsburgh Fatigability Scale (PFS, 0–50) to assess perceived physical fatigability, and the PROMIS Physical Function 20a* to assess physical function. We grouped participants into three age categories: 80–84 (n = 51), 85–89 (n = 51), and 90+ (n = 20) years. Multiple linear regression revealed that a lower HEI was associated with higher PFS Physical score after adjusting for age group, sex, body mass index, and the number of medical conditions (p = 0.001). Several macro- and micro-nutrient intakes were also lower in those reporting more (≥15) compared to less (<15) perceived physical fatigability. Mediation analysis revealed that PFS Physical scores explained ~65% (p = 0.001) of the association between HEI total score and PROMIS19 Physical Function score. Poor diet quality may contribute to more perceived physical fatigability, which could exacerbate impairments in the oldest-old’s physical function.

Highlights

Impairments in physical function remain hallmark clinical manifestations of sarcopenia, dynapenia, and frailty in older adults [1,2]
We found that the Healthy Eating Index (HEI) total score had a natural indirect effect (β = 0.123, 95% confidence intervals (95% CI) = 0.05–0.21, p = 0.001) on the PROMIS19 Physical Function score, indicating that the Pittsburgh Fatigability Scale (PFS) Physical score explained ~65% (p = 0.001) of the association between the HEI total score and the PROMIS19 Physical Function score
We found that the HEI protein score had a total effect (β = 4.019, 95% CI = 1.27–6.77, p < 0.001) on the PROMIS19 Physical Function score (Figure 2B)

Summary

Introduction

Impairments in physical function remain hallmark clinical manifestations of sarcopenia, dynapenia, and frailty in older adults [1,2]. Older adults who have a lower self-reported or objectively measured physical function are at increased risk of hospitalization and all-cause mortality [4,5,6]; understanding the mechanisms contributing to impairments in physical function remains clinically relevant. Higher levels of perceived physical fatigue, known as physical fatigability, was recently shown to be associated with lower levels of physical function, including slower walking speeds during the 400-m walk test [7], and have been shown to predict impending declines in physical function in older adults [8]. Recent results suggest that more perceived physical fatigability is a potential mediator in the disablement pathway [9]

Methods

Results

Discussion

Conclusion