The Iwanuma Study (R01AG042463-04) was established with the objective to investigate the role of social cohesion in promoting disaster resilience among older survivors of the March 11, 2011 earthquake and tsunami in northeastern Japan. Our baseline data were gathered as part of a nationwide cohort study in Japan ? the JApan Gerontological Evaluation Study (JAGES) -- seven months prior to the disaster. One of the field sites of the JAGES cohort was the city of Iwanuma in Miyagi Prefecture, 80 km west of the earthquake epicenter. We managed to locate 99.7% of the surviving participants approximately 3 years after the disaster. To date, the Iwanuma study has established that: (a) 11 percent of survivors are experiencing severe PTSD symptoms three years after the disaster, and that higher levels of community social cohesion pre-dating the disaster lowers the odds of severe PTSD symptoms (odds ratio 0.7, 95% CI: 0.6 ? 0.9) (Am J Epidemiol, March 2016); (b) housing damage and residential relocation is associated with cognitive impairment among survivors (Proc Natl Acad Sci, September 2016); and (c) informal socializing with neighbors buffers the adverse impact of disaster experience on cognitive decline (Lancet Planetary Health in press). In this competing renewal, we seek to extend our follow-up of the impacts of disaster experience on the health of aging survivors, focusing specifically on three aging-related outcomes: cognitive decline, functional disability, and overweight. Our project is innovative for several reasons. First, our study design leverages a unique ?natural experiment? made possible by the collection of individual data pre-dating the 2011 Tohoku disaster. Secondly, we focus on outcomes that are relevant to the health needs of older populations affected by disaster, viz. cognitive function, functional independence, and nutritional status. The elderly are disproportionally affected both during and after disasters, because of chronic diseases or conditions, impaired physiological, sensory, and cognitive changes experienced as part of aging. Thirdly, our proposal addresses an important gap in knowledge by documenting the long-term health trajectories after disaster, in contrast to previous literature which has mostly focused on the immediate/short-term health effects. Fourthly, our analyses will utilize four survey waves which is seldom available in disaster situations: 2010 (pre-disaster), 2013, 2016, and a 4th wave planned in 2019. These data will enable us to examine at least two occasions on which survivors experienced a large-scale change in residential environment. Lastly, our study will utilize objective measures of exposure (e.g. housing damage as assessed by building inspectors; GIS data on local food environment) as well as health status (e.g. dementia symptomatology and disability status obtained from in-home assessment under Japan?s Long Term Care Insurance registry).
The incidence of natural disasters is increasing worldwide. The significance of our study is that older populations are disproportionally affected by disasters. By focusing on age-related health outcomes (cognitive impairment, functional disability, and metabolic abnormalities) over 4 waves of data collection, our study will assist in understanding the longer-term health impacts of disaster exposure in a vulnerable population.
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