Nearly a quarter of those who died of illness or stress linked to the March 2011 earthquake and tsunami in the hardest-hit prefectures were people with disabilities, a Kyodo News survey released Sunday showed.

Disabled people accounted for 24.6 percent of total "disaster-related deaths" in Fukushima, Iwate and Miyagi prefectures, far above their 7 percent representation among the population as a whole as estimated by the health ministry.

It is also much higher than the around 14 percent who were aged over 65, many of whom died after the disaster on March 11, 2011, because of deteriorating health and living conditions in shelters and other evacuation facilities.

The survey, which targeted 42 municipalities in the prefectures affected by the quake, tsunami and ensuing nuclear crisis, was carried out ahead of the ninth anniversary of the disaster.

The number of people who died of indirectly related causes totaled 1,500 in the 32 municipalities that responded to the survey.

Of the total, 370 were people with disabilities, of whom 352 had a physical disability.

"Some couldn't go to crowded evacuation centers and lived in physically challenging conditions, inside large vehicles or on the second floor of inundated houses, for example," said Kazuhiko Abe, a Tohoku Fukushi University professor.

"Temporary housing was highly stressful, too," Abe said, noting that many such facilities were not designed to accommodate people with physical disabilities.

The survey showed the lasting impact of the ordeal on such communities.

"We need to set up a framework so that disabled people won't be left without assistance," the professor said.

As of Sept. 30 last year, there had been 3,739 deaths in total across the country caused by stress or illness that was worsened due to the disaster, according to the Reconstruction Agency. About 60 percent of them were reported in Fukushima Prefecture, which was at the center of the nuclear crisis.