Impact of exercising alone and exercising with others on the risk of cognitive impairment among older Japanese adults

https://doi.org/10.1016/j.archger.2022.104908Get rights and content

Highlights

  • Older adults are more likely to exercise alone than with others.

  • Exercising alone for ≥ 2x/wk decreases the risk of cognitive impairment.

  • Exercising with others for ≥ 2x/wk decreases the risk of cognitive impairment.

  • If everyone exercises alone for ≥ 2x/wk, 15.1% of the incidence can decrease.

  • If everyone exercises with others for ≥ 2x/wk, 29.2% of the incidence can decrease.

Abstract

Purpose

This longitudinal study investigates the influence of the stratified frequency of exercising alone and exercising with others on the prevention of cognitive impairment among older Japanese adults.

Methods

This four-year follow-up study targeted 4,358 individuals (mean age: 76.9 ± 5.6 years, female: 51.8%) who participated in an inventory mail survey in one region of Japan. The exercise forms surveyed involved the frequency of exercising alone and with others. Cognitive impairment was assessed using the nationally standardized dementia scale proposed by the Ministry of Health, Labour and Welfare of Japan. Adjusted Cox proportional-hazard models were used to examine the association between the exercise forms and the development of cognitive impairment, and calculate population-attributable fractions (PAFs).

Results

The cumulative incidence of cognitive impairment throughout the study was 7.7%. Participants who exercised ≥ 2 times/week alone (hazard ratio [HR] = 0.78; 95% confidence interval [CI] = 0.61–0.998) had a lower risk of developing cognitive impairment than those who did not exercise alone. Similarly, participants who exercised ≥ 2 times/week with others (HR = 0.66; 95% CI = 0.47–0.94) showed a lower risk of developing cognitive impairment than those who did not exercise with others. The scenarios involving PAFs demonstrated that, if all participants exercised alone or with others ≥ 2 times/week, the risk of cognitive impairment decreased by 15.1% and 29.2%, respectively.

Conclusion

Both forms of exercise reduced the development of cognitive impairment, with exercising with others potentially being highly effective in preventing cognitive impairment.

Introduction

In 2019, 57.4 million people were suffering from dementia globally, and this number is projected to increase to 152.8 million by 2050 (GBD 2019 Dementia Forecasting Collaborators, 2022). Dementia severely impacts patients’ quality of life (Prince et al., 2015) and imposes a heavy burden on caregivers (Prince et al., 2012). Direct medical costs, direct social care costs, and costs of informal care approaches for dementia are significantly expensive (Wimo et al., 2017). Therefore, currently, there is increasing interest in modifiable risk factors for the prevention of dementia (Livingston et al., 2020).

Physical activity and exercise have been identified as modifiable factors for the prevention of dementia (Livingston et al., 2020). Owing to the advantages of increased accessibility and cost-effectiveness, as well as other health-related benefits, many studies have examined the effects of exercise and physical activity on the prevention of dementia (Northey et al., 2018; Xu et al., 2017). A meta-analysis investigating the association between leisure-time physical activity and dementia found a dose-response relationship (Xu et al., 2017). Another meta-analysis involved the effects of exercise interventions of at least moderate intensity lasting at least 45 min per session on as many days of the week as possible, and established that the approach used was beneficial for maintaining cognitive function among adults aged over 50 years (Northey et al., 2018).

Over recent years, there has been an increased focus on the positive impact of exercising with others on health outcomes (Kanamori et al., 2015). Cross-sectional studies reported higher objective measures of physical and cognitive function and lower rates of falls among individuals who exercised with others than among those who exercised alone (Fujii et al., 2021; Hayashi et al., 2018). Longitudinal studies have established that those who exercised with others have a lower risk of developing depression and functional disability than those who do not exercise. This association was not established among individuals who exercised alone (Fujii et al., 2020; Kanamori et al., 2018). The mechanisms by which exercise with others can affect health outcomes are likely to involve physical activity as well as psychological and social factors (Kanamori et al., 2015). Exercising with others has been reported to ensure a high likelihood of achieving the World Health Organization's recommendation of 150 or more minutes of moderate- to vigorous-intensity physical activity per week (Seino et al., 2019; World Health Organization, 2020), to reduce stress, anxiety, and depression (Street et al., 2007) and promote enhanced social connectedness, social support, and peer bonds (Eime et al., 2013).

Social contact is a modifiable risk factor for dementia (Livingston et al., 2020; Samtani et al., 2022). A recent meta-analysis focusing on social interaction examined its association with cognitive function, and reported that community group engagement and interaction with family and friends were effective in maintaining cognitive function (Samtani et al., 2022). In terms of preventing cognitive impairment, exercising with others may be more beneficial than exercising alone, as it has a positive effect on social factors (Kim et al., 2019). However, few studies have investigated the influence of exercising with others on the prevention of cognitive impairment. A previous study reported that older adults who congregated and participated in social activities involving light physical activity had a lower risk of cognitive impairment in the future (Hikichi et al., 2017). Further, a six-year follow-up study reported that group participation in community-level sports had a preventive effect on cognitive impairment (Tsuji et al., 2019). However, previous studies have only investigated participation in exercise groups, and were unable to examine exercising outside the groups with others (Hikichi et al., 2017; Tsuji et al., 2019). Additionally, existing studies have not stratified the frequency of exercise when examining the relationship between exercise forms and cognitive function (Hikichi et al., 2017; Tsuji et al., 2019). The frequency of exercising is associated with enhanced cognitive function (Northey et al., 2018), and stratifying this frequency is essential for extending exercise-related recommendations, with improved cognitive functions as the outcome. The frequencies of each form of exercise may vary and would affect future cognitive function. Considering this practical information can aid the creation of specific exercise support measures to maintain cognitive function. As the prevalence of specific behaviors is also a crucial factor impacting assessment and decision-making in the field of public health, it is beneficial to show the impact of each form of exercise on the prevention of cognitive impairment by utilizing a population-attributable fraction (PAF) (Zhang et al., 2018). Therefore, in this study, we estimated the PAFs for reducing cognitive impairment resulting from exercising alone and exercising with others.

This study aimed to compare the influence of each exercise form on the prevention of cognitive impairment and examine the influence of the stratified frequency of exercising alone and exercising with others on the prevention of cognitive impairment to identify the exercise form that is most beneficial in preserving cognitive function. We hypothesized that exercising with others would be more influential than exercising alone for preventing cognitive impairment, and that this influence would increase with the increase in frequency.

Section snippets

Study design and participants

This study is part of the Kasama study, which is an inventory mail survey that targeted community-dwelling older residents (aged ≥ 65 years) in Kasama City, Ibaraki, Japan. Supplementary Fig. 1 shows the flow of the participants involved in this study. The data obtained from the second-wave survey were used as the baseline. In the first wave, self-report questionnaires were sent to 16,870 older adults who were not receiving long-term care insurance (Tsutsui & Muramatsu, 2005). A total of 10,339

Results

Table 1 presents the descriptive data of the sample. At the baseline, the mean age was 76.9 ± 5.6 years, and 51.8% of the participants were female. Supplementary Tables 1 and 2 show the demographic characteristics of the groups involving the participants exercising alone and those exercising with others. Significant differences were established in exercise practice frequency and age, education level, subjective economic status, living alone, smoking, BMI, dyslipidemia, sleep duration, and

Discussion

To the best of our knowledge, this is the first study to compare the impact of exercise forms (exercising alone and exercising with others) and the effect of the frequency of practicing these exercise forms on the prevention of cognitive impairment. In the multivariable-adjusted Cox proportional hazards model, it was established that exercising with others may be more effective than exercising alone, with regard to the prevention of cognitive impairment. Additionally, exercising alone or with

Conclusion

This study established that both forms of exercise were effective in preventing cognitive impairment. Furthermore, exercising with others may be more useful in reducing the risk of cognitive impairment than exercising alone, which was the prevalent exercise form in this study. Regarding the scenario in which all participants exercised with others for ≥ 2 times a week, the risk of developing cognitive impairment decreased by 29.2%. This impact was larger than the scenario in which participants

Author contributions

KN and KT designed the study and analyzed the data. KN drafted the manuscript. All authors collected the data. KN, KT, TJ, and TO acquired the funding required to conduct this study. TO administered the project. All the authors critically revised the manuscript, interpreted the results, and approved the final version of the manuscript for submission.

Funding

This study was supported by a JSPS KAKENHI Grant-in-Aid for Scientific Research (B) (20H04063) to TO and by grants from Young Scientists (B) (26750348) to KT, JST COI-NEXT (JPMJPF2017) to TO, JST SPRING (JPMJSP2124) to KN, the Meiji Yasuda Life Foundation of Health and Welfare to TJ, and the Japan Sports Association to TO.

Declaration of Competing Interest

The authors report no declarations of interest.

Acknowledgments

We thank the participants involved in this study and Kasama City officials for their cooperation throughout this study. We would like to thank Editage (www.editage.com) for English language editing.

References (44)

  • Y. Fujii et al.

    Associations between exercising in a group and physical and cognitive functions in community-dwelling older adults: A cross-sectional study using data from the Kasama Study

    Journal of Physical Therapy Science

    (2021)
  • E. Fukutomi et al.

    Relationships between each category of 25-item frailty risk assessment (Kihon Checklist) and newly certified older adults under Long-Term Care Insurance: A 24-month follow-up study in a rural community in Japan

    Geriatrics & Gerontology International

    (2015)
  • Estimation of the global prevalence of dementia in 2019 and forecasted prevalence in 2050: An analysis for the Global Burden of Disease Study 2019

    Lancet Public Health

    (2022)
  • K. Harada et al.

    Social interaction in walking groups and affective responses among Japanese older adults

    Journal of Aging and Physical Activity

    (2020)
  • T. Hayashi et al.

    Differences in falls between older adult participants in group exercise and those who exercise alone: A cross-sectional study using Japan Gerontological Evaluation Study (JAGES) data

    International Journal of Environmental Research and Public Health

    (2018)
  • H. Hikichi et al.

    Increased risk of dementia in the aftermath of the 2011 Great East Japan Earthquake and Tsunami

    Proceedings of the National Academy of Sciences of the United States of America

    (2016)
  • S. Hisano

    The relationship between Revised Hasegawa Dementia Scale (HDS-R), Mini-Mental State Examination (MMSE) and Bed-fast Scale, dementia scale

    Japan Phychogeriatric Society

    (2009)
  • S. Holmquist et al.

    The association of depression with subsequent dementia diagnosis: A Swedish nationwide cohort study from 1964 to 2016

    PLOS Medicine

    (2020)
  • S. Kanamori et al.

    Participation in sports organizations and the prevention of functional disability in older Japanese: The AGES Cohort Study

    PloS One

    (2012)
  • S. Kanamori et al.

    Group exercise for adults and elderly: Determinants of participation in group exercise and its associations with health outcome

    The Journal of Physical Fitness and Sports Medicine

    (2015)
  • S. Kanamori et al.

    Exercising alone versus with others and associations with subjective health status in older Japanese: The JAGES cohort study

    Scientific Reports

    (2016)
  • S. Kanamori et al.

    Frequency and pattern of exercise and depression after two years in older Japanese adults: The JAGES longitudinal study

    Scientific reports

    (2018)
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