Article Text
Abstract
Purpose The proportion of elderly individuals (age ≥65 years) in Japan reached 27.7% in 2017, the highest in the world. A serious social problem in a super-aged society is the rise in the number of elderly people who need long-term care (LTC), which is mainly due to cerebrovascular disease, dementia, age-related frailty, falls and fractures, and joint disease. We hypothesised that decreased muscle mass, muscle strength and insulin sensitivity are the common risk factors for these diseases related to needing LTC. We developed a prospective cohort study of elderly subjects in an urban community to test this hypothesis. The primary objective is to prospectively investigate associations between muscle mass, muscle strength, and insulin sensitivity and incidence of main disease and risk factors of needing LTC. The primary outcomes are the incidence of cerebrovascular disease and cognitive decline.
Participants Participants were 1629 people aged 65–84 years living in 13 communities in an urban area (Bunkyo-ku, Tokyo, Japan). Average age was 73.1±5.4 years.
Findings to date We obtained baseline data on cognitive function, cerebral small vessel disease (SVD) determined by brain MRI, body composition, bone mineral density, arteriosclerosis, physical function, muscle mass, muscle strength and insulin sensitivity. Mild cognitive impairment and dementia were observed in 18.1% and 3.3% of participants, respectively. The prevalence of cerebral SVD was 24.8%. These characteristics are similar to those previously reported in elderly Japanese subjects.
Future plans We will ask participants about their health status, including incidence of cerebrovascular disease, falls, fractures and other diseases every year by mail. We plan to re-evaluate cognitive function, brain MRI parameters and other parameters at 5 and 10 years after the baseline evaluation. We will evaluate whether low muscle function (muscle mass, muscle strength or insulin sensitivity) is a risk factor for cognitive decline or cerebrovascular disease.
- muscle mass
- muscle strength
- insulin sensitivity
- long-term care
- community based study
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Footnotes
Contributors YS, YT, HK, HW and RK conceived the study and obtained grant funding. YS, YT and HK drafted the protocol. SN advised on the statistical analysis. KS, HD, MI, KK, TM, SH, SK, SA, NH, YM and HN reviewed and revised the protocol.
Funding This work is supported by the Strategic Research Foundation at Private Universities (S1411006) and KAKENHI (18H03184) from the Ministry of Education, Culture, Sports, Science and Technology of Japan, the Mizuno Sports Promotion Foundation, and the Mitsui Life Social Welfare Foundation.
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Competing interests None declared.
Patient consent for publication Not required.
Ethics approval This study protocol was approved by the ethics committee of Juntendo University in November 2015 (no. 2015078, 2016138, 2016131 and 2017121). This study is being carried out in accordance with the principles outlined in the Declaration of Helsinki.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement No data are available.