Dose–Response Relationships between Objectively Measured Daily Steps and Mortality among Frail and Nonfrail Older Adults

Medicine and Science in Sports and Exercise · 6 authors, 7 centres

AI SUMMARY

FIDELITY 100%

POPULATION4165 community-dwelling older adults aged 65 years or older from the Kyoto–Kameoka study in Japan.

INTERVENTIONObjectively measured daily steps using a triaxial accelerometer.

COMPARISONFrail versus nonfrail status, assessed using the validated Kihon Checklist.

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AGENT 01 · STRUCTURED SUMMARY

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TL;DR

This prospective cohort study found that the dose-response relationship between daily steps and mortality differs between frail and nonfrail older adults, with frail individuals requiring more steps to see a mortality benefit.

Full summary

1,156 CHARS

This prospective cohort study analyzed data from 4165 community-dwelling older adults in Japan who wore an accelerometer to measure daily steps and were followed for mortality. The study aimed to compare the dose-response relationship between daily steps and mortality in frail versus nonfrail individuals. Frailty was assessed using a validated checklist. The study found an inverse association between step count and mortality overall, with the top quartile (average 7502 steps/day) having a lower hazard ratio for mortality than the bottom quartile (average 1786 steps/day). Stratified analysis revealed that for nonfrail individuals, the mortality hazard ratio plateaued at approximately 5000–7000 steps per day, while for frail individuals, an inverse relationship was observed at approximately 5000 steps or more per day. Limitations include potential selection bias, a relatively short median follow-up of 3.38 years, baseline-only step count measurement, and possible residual confounding. The findings suggest frailty status influences the step count threshold for mortality benefit, which may inform physical activity guidelines for older adults.

PICO

PPOPULATION

4165 community-dwelling older adults aged 65 years or older from the Kyoto–Kameoka study in Japan.

IINTERVENTION

Objectively measured daily steps using a triaxial accelerometer.

OOUTCOME

All-cause mortality.

STUDY TYPE

cohort

SPECIALTY

epidemiology

SUMMARISED BY

AI pipeline

FIDELITY CHECK

100% · A

ORIGINAL PAPER

PMC10184809

Dose–Response Relationships between Objectively Measured Daily Steps and Mortality among Frail and Nonfrail Older Adults

Medicine and Science in Sports and Exercise

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ABSTRACT

ABSTRACT Purpose Whether the association between objectively assessed physical activity and mortality differs between adults with versus those without frailty is unclear. We investigated this association in community-dwelling older adults. Methods This prospective study used the data of 4165 older adults 65 yr or older from the Kyoto–Kameoka study in Japan who wore a triaxial accelerometer (EW-NK52). The number of steps was classified by quartiles using the average daily value of data obtained from the accelerometer across four or more days. Frailty was evaluated using the validated Kihon Checklist. We evaluated the association between mortality and daily steps using a multivariable Cox proportional hazards analysis and restricted spline model. Results The average daily steps for the first, second, third, and fourth quartiles were 1786, 3030, 4452, and 7502, respectively. In total, 113 deaths were recorded during a median follow-up of 3.38 yr (14,061 person-years). After adjusting for confounders, the top quartile was associated with a lower hazard ratio (HR) for mortality than the bottom quartile (HR = 0.39, 95% confidence interval = 0.18–0.85). In a stratified model by frailty status, the daily step count dose–response curve at which the HR for mortality plateaued among nonfrail individuals was approximately 5000–7000 steps per day. By contrast, the daily step count showed an inverse relationship with mortality at approximately 5000 steps or more per day in frail individuals. Conclusions The relationship between daily steps and mortality is different between those with and those without frailty, and people with frailty may require more daily steps than those with nonfrailty to achieve the inverse relationship with mortality. These findings may be useful for informing future physical activity guidelines.

CITATION EXPORT

DAIKI WATANABE, TSUKASA YOSHIDA, YUYA WATANABE et al.. Dose–Response Relationships between Objectively Measured Daily Steps and Mortality among Frail and Nonfrail Older Adults. Medicine and Science in Sports and Exercise. (2023). https://doi.org/10.1249/MSS.0000000000003133

AUTHORS

6 · 7 CENTRES

DAIKI WATANABE, TSUKASA YOSHIDA, YUYA WATANABE, YOSUKE YAMADA, MOTOHIKO MIYACHI, MISAKA KIMURA

1Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama, JAPAN
2National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, Shinjuku-ku, Tokyo, JAPAN
3Institute for Active Health, Kyoto University of Advanced Science, Kameoka, Kyoto, JAPAN
4Senior Citizen’s Welfare Section, Kameoka City Government, Kameoka, Kyoto, JAPAN
5Physical Fitness Research Institute, Meiji Yasuda Life Foundation of Health and Welfare, Hachioji, Tokyo, JAPAN
6Department of Nursing, Doshisha Women’s College of Liberal Arts, Kyotanabe, Kyoto, JAPAN
7Laboratory of Applied Health Sciences, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto, JAPAN