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Physical activity and incident dementia in older Japanese adults: The Okayama study
Author(s) -
Liu Yangyang,
Mitsuhashi Toshiharu,
Yamakawa Michiyo,
Sasai Megumi,
Tsuda Toshihide,
Doi Hiroyuki,
Hamada Jun
Publication year - 2019
Publication title -
international journal of geriatric psychiatry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 129
eISSN - 1099-1166
pISSN - 0885-6230
DOI - 10.1002/gps.5135
Subject(s) - hazard ratio , confidence interval , dementia , medicine , proportional hazards model , cohort study , incidence (geometry) , multivariate analysis , gerontology , demography , cohort , physics , disease , sociology , optics
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.