Elderly at Greater Risk For Dementia After Natural Disasters, New Study Says

Pam Wright
Published: November 1,2016

The elderly have a greater risk of developing dementia after a natural disaster, researchers say.
According to a recent study conducted by researchers at Harvard University's T.H. Chan School of Public Health, the loss of property and loved ones in the aftermath of a natural disaster increases the symptoms of dementia in the elderly.
The study, published in the Proceedings of the National Academy of Sciences journal (PNAS), looked at the elderly victims of the 2011 Great East Japan Earthquake and subsequent tsunami and found that people 65 and older who lost their homes were much more likely to experience increased symptoms of dementia than those who were able to remain in their homes.
“In the aftermath of disasters, most people focus on mental health issues like PTSD,” said Dr. Hiroyuki Hikichi, a research fellow at Harvard Chan School and lead author of the study, according to Reuters. “But our study suggests that cognitive decline is also an important issue. It appears that relocation to a temporary shelter after a disaster may have the unintended effect of separating people not just from their homes but from their neighbors — and both may speed up cognitive decline among vulnerable people.”

The earthquake that struck Japan in March 2011 generated a devastating tsunami that was observed all over the Pacific and caused tremendous devastation locally, including an accident at the Fukushima Daiichi Nuclear Power Plant.
(Patrick Fuller. IFRC/NOAA)

The researchers, working alongside colleagues in Japan, used the data of 3,594 elderly residents who had participated in a health survey as part of an ongoing study of aging known as the Japan Gerontological Evaluation Study (JAGES). The survey was conducted in the coastal city of Iwanuma, which is approximately 50 miles from the epicenter of the earthquake.
According to the study, the initial survey examined the subjects' health status, health behaviors, social determinants of healthy aging and the prevalent symptoms of dementia. At the time, 4.1 percent of the participants assessed had symptoms of dementia and 54 percent presented with signs of hypertension.
A second survey was conducted by the Harvard team on the same participants two-and-a-half years after the tsunami.
The survey revealed the out of 3,566 survivors of the tsunami disaster, 38 percent reported that they lost relatives and/or friends and 58.9 percent reported property damage.
The second survey revealed that the number of participants suffering symptoms of dementia had jumped to 11.5 percent and the prevalence of hypertension had risen to 57.2 percent. The prevalence of stroke after the tsunami nearly doubled, from 1.5 percent to 2.9 percent.
(VIDEO: Map Shows Path of 2011 Japan Tsunami)
Those who were forced to move to temporary housing after their homes were either significantly damaged or destroyed had the highest levels of cognitive decline, which seemed to increase depending on the severity of the damage.
The loss of relatives and/or friends did not seem to impact cognitive abilities, which came as a surprise to the researchers, because many studies have concluded that a strong social network is important for cognitive health, according to the study.
According to arstechnica.com, previous studies have surmised that there may be a connection between natural disasters and cognitive decline, but this is the first study of its kind to do so.
MORE: Before and After the Japan Tsunami