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.
Keywords: community based study; insulin sensitivity; long-term care; muscle mass; muscle strength.
© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.
Conflict of interest statement
Competing interests: None declared.
Caregiver- and patient-directed interventions for dementia: an evidence-based analysis.Ont Health Technol Assess Ser. 2008;8(4):1-98. Epub 2008 Oct 1. Ont Health Technol Assess Ser. 2008. PMID: 23074509 Free PMC article.
Interventions for preventing delirium in older people in institutional long-term care.Cochrane Database Syst Rev. 2019 Apr 23;4(4):CD009537. doi: 10.1002/14651858.CD009537.pub3. Cochrane Database Syst Rev. 2019. PMID: 31012953
Prevention of falls and fall-related injuries in community-dwelling seniors: an evidence-based analysis.Ont Health Technol Assess Ser. 2008;8(2):1-78. Epub 2008 Oct 1. Ont Health Technol Assess Ser. 2008. PMID: 23074507 Free PMC article.
Toward the realization of a better aged society: messages from gerontology and geriatrics.Geriatr Gerontol Int. 2012 Jan;12(1):16-22. doi: 10.1111/j.1447-0594.2011.00776.x. Geriatr Gerontol Int. 2012. PMID: 22188494 Review.
Screening for Cognitive Impairment in Older Adults: An Evidence Update for the U.S. Preventive Services Task Force [Internet].Rockville (MD): Agency for Healthcare Research and Quality (US); 2013 Nov. Report No.: 14-05198-EF-1. Agency for Healthcare Research and Quality (US). 2013. PMID: 24354019 Free Books & Documents. Review.
- World population Prospects：The 2017 revision: United nations, 2017. Available: https://population.un.org/wpp/
- Annual Report on the Aging Society 2018 Cabinet office, government of Japan, 2017. Available: http://www8.cao.go.jp/kourei/whitepaper/w-2018/html/gaiyou/index.html [Accessed 27 Oct 2018].
- HealthandWelfareBureaufortheElderly Long-Term care insurance system of Japan. MinistryofHealth, LabourandWelfare, 2016.