This article is a collaboration between MedPage Today and:
People who escaped the immediate destruction caused by the Great East Japan Earthquake -- and resulting tsunami -- on March 11, 2011 were not out of the woods, as illustrated by significantly elevated rates of out-of-hospital cardiac arrest in the weeks following the disaster.
The epicenter of the earthquake -- which measured 9.0 on the Richter scale -- was off the northeast coast of Japan, and the brunt of the damage from the trembling and the surge of water was sustained by three prefectures -- Iwate, Miyagi, and Fukushima. In those areas, a total of 15,814 people died and another 2,664 went missing.
Previous research has identified a relationship between earthquakes and the risk of sudden cardiac arrest, and Taku Iwami, MD, PhD, of the in Japan, and colleagues wanted to find out whether a similar association was seen after the Japanese disaster.
As reported in the Nov. 28 issue of the , the researchers looked at data from adult patients transferred to centers in the hardest hit prefectures after an out-of-hospital cardiac arrest from 4 weeks before to 8 weeks after March 11, 2011. They compared rates of cardiac arrest during each week with the expected rates for 2011 and the preceding 6 years.
The risk of out-of-hospital cardiac arrest was significantly elevated for the week following the earthquake (risk ratio 1.70) and for each of the 3 subsequent weeks (RRs 1.48, 1.47, and 1.26) before returning to the expected rate. No such deviations surrounding that date were seen in the previous 6 years.
There were some differences by age and sex, however. The risk of cardiac arrest was not elevated in men ages 18 to 74 during any week, but it was increased in older men in the first 2 weeks after the earthquake and in the first week after maximum aftershocks occurred on April 7 and 11.
Risk was increased in women ages 18 to 74 for the first 2 weeks after the earthquake, and in older women for the first, third, and fourth weeks after the earthquake.
The researchers believe "that the earthquake triggered mental and physical stress among people living in disaster areas, [which] became the cause of sudden cardiac arrest," Iwami wrote in an email to MedPage Today.
The differences in the findings according to age and sex "would be helpful information concerning where, when, and for whom emergency treatments should be provided after great disasters worldwide," he said. "In addition, these data suggest that long-term healthcare countermeasures would be needed in case of serious disaster that forces the majority of people (especially the elderly) to evacuate for months."
Cardiac arrest was not the only problem exacerbated by the earthquake. A study presented at the 2012 meeting of the European Society of Cardiology and published in the European Heart Journal showed that heart failure and stroke cases also spiked in Miyagi in the aftermath of the disaster.
During the meeting, the researcher who presented the findings, , of Tohoku University Graduate School of Medicine in Sendai, Japan, said, "We consider that the increased occurrences of cardiovascular diseases may have been caused by the activated sympathetic nervous system by physical and mental stresses, insufficient medications, and increased salt intake from preserved foods."
"While hospitals and pharmacy services were disrupted by the earthquake and tsunami, these services were restored rapidly and we do not believe [those disruptions] contributed greatly to the cardiovascular diseases we observed following the disaster," Shimokawa said.