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

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.

Dose‐response relationship between late‐life physical activity and incident dementia: A pooled analysis of 10 cohort studies of memory in an international consortium

“…The majority of previous studies measured only one or two components of late-life physical activity (see Box 1 ). Some measured only the frequency of physical activity [6][7][8][9] while others measured the weighted duration of physical activity. [10][11][12] Some studies assessed the combination of frequency and intensity of physical activity.…”

“…A few previous studies have examined the potential doseresponse relationship between late-life physical activity and dementia risk. [6][7][8][9][10][11][12][13][14][15][16] However, many studies did not collect detailed information on the duration, frequency, and intensity of physical activity for the calculation of amount (the product of duration, frequency, and inten-sity), instead measuring only the frequency or duration of physical activity. [6][7][8][9][10][11][12] In a few studies that did calculate the amount, the categorization of physical activity varied considerably and the results were inconsistent.…”

“…[6][7][8][9][10][11][12][13][14][15][16] However, many studies did not collect detailed information on the duration, frequency, and intensity of physical activity for the calculation of amount (the product of duration, frequency, and inten-sity), instead measuring only the frequency or duration of physical activity. [6][7][8][9][10][11][12] In a few studies that did calculate the amount, the categorization of physical activity varied considerably and the results were inconsistent. 15,16 This makes it difficult to compare results across previous studies based on heterogeneous assessments and disparate categorizations of physical activity.…”

“…Understanding the dose‐response association between physical activity and dementia is essential to both the design of intervention studies and the development of evidence‐based guidelines for physical activity. A few previous studies have examined the potential dose‐response relationship between late‐life physical activity and dementia risk 6–16 . However, many studies did not collect detailed information on the duration, frequency, and intensity of physical activity for the calculation of amount (the product of duration, frequency, and intensity), instead measuring only the frequency or duration of physical activity 6–12 .…”

The Association between Estimated Cardiorespiratory Fitness and Mental Health in Older Adults

“…특히 생활습관 요인 중 신체활동은 우울과 치매를 예방하고 임상증 상을 완화 혹은 치료하는 데 있어 효과적인 역할을 할 뿐만 아니라 [14][15][16][17][18][19] 우울과 치매를 독립적으로 예측하는 것으로도 보고되고 있다 [20,21]. 생리학적으로 신체활동은 세로토닌과 도파민의 분비를 자극하고 우 울과 연관된 염증성 싸이토카인의 분비를 낮추며 [22][23][24], 뉴런의 세포 사멸을 억제하고 기억형성에 도움이 되는 뇌유래신경영양인자(BDNF) 의 생성을 유도하는 [25,26]…”