Physical activity and incident dementia in older Japanese adults: The Okayama study

Yangyang Liu, Toshiharu Mitsuhashi, Michiyo Yamakawa, Megumi Sasai, Toshihide Tsuda, Hiroyuki Doi, Jun Hamada

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Objective: To evaluate the association between regular physical activity and the risk of incident dementia in older Japanese adults. Methods: This was a retrospective cohort study performed in Okayama City, Japan. Overall, 51 477 older Japanese adults were followed from 2008 to 2014. A health checkup questionnaire was used to assess regular physical activity. The Dementia Scale of long-term care insurance was used as a measure of incident dementia. Cox proportional hazard models were used to calculate adjusted hazard ratios, with their 95% confidence intervals, for the incidence of dementia across the categories of physical activity. Results: During a 7-year follow-up, 13 816 subjects were considered as having incident dementia. Compared with participants who performed physical activity less than or equal to one time per week, the multivariate adjusted hazard ratio values (95% confidence intervals) for participants who performed physical activity greater than or equal to two times per week but not every day and those who performed physical activity every day were 0.79 (0.75-0.84) and 0.94 (0.89-0.98), respectively. The interaction of physical activity and sex was statistically significant (P <.01). In subgroup analysis, the multivariate-adjusted hazard ratio values (95% confidence intervals) remained low, at 0.76 (0.70-0.84) in males and 0.81 (0.76-0.87) in females who performed physical activity greater than or equal to two times per week but not every day; they were 0.82 (0.76-0.89) in males and 1.01 (0.95-1.07) in females who performed physical activity every day. Conclusions: Regular physical activity could reduce the risk of incident dementia in older Japanese adults, except females who performed physical activity every day.

Original languageEnglish
Pages (from-to)1429-1437
Number of pages9
JournalInternational Journal of Geriatric Psychiatry
Volume34
Issue number10
DOIs
Publication statusPublished - Oct 1 2019

Keywords

  • Japanese
  • cohort study
  • dementia
  • elderly
  • long-term care insurance
  • physical activity

ASJC Scopus subject areas

  • Geriatrics and Gerontology
  • Psychiatry and Mental health

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