Survivors of major earthquakes may not be safely out of the woods. The emotional stress from an earthquake and the mayhem that follows may boost the rate of fatal heart attacks long after the disaster, according to a study of the October 2004 Niigata-Chuetsu earthquake in Japan.

The findings of the study are “a vivid reminder that the medical after-effects of natural disasters are not limited to physical injury or emotional distress,” Dr. Andrew Steptoe of University College London notes in an editorial accompanying the study, which is published in the journal Heart.

Studies from around the world have shown increases in fatal heart attacks in the short-term after earthquakes, including after the Niigata-Chuetsu earthquake, Dr. Kazutoshi Nakamura of Niigata University in Niigata City and colleagues note in their report.

While the Niigata-Chuetsu quake’s immediate death toll was relatively low, infrastructure damage to the mountainous rural area was extremely disruptive, with 9,000 people living in temporary housing a year after the event, and 5,000 still there two years afterwards. “Although temporary housing ended in December 2007, a number of people continued to struggle to reconstruct their lives owing to financial losses,” Nakamura and his team report.

To investigate whether these stresses might have had long-term effects on the heart among people living in the area, the researchers looked at death rates 5 years before and 3 years after the quake in the affected area and in a control area outside the earthquake zone.

While there was no significant difference in heart attack death rates before and after the earthquake in the control area, heart attack deaths did increase significantly in the disaster area, from 47.3 per 100,000 persons per year to 53.9 per 100,000 persons per year.

The pattern was the same for men and women and the increase did not get smaller over time.

Japan has the world’s lowest acute heart attack death rate, the researchers note, so parts of the world where heart attack deaths are higher would probably see more deaths after similar disasters.

Steptoe says earthquake-related “damage to property, loss of livelihood, delays in reconstruction, upset of daily routines and disruption of social communities” likely led to “persistent distress” and hence increased deaths due to heart attack.

“During the present era of climate change and the experience in many parts of the world of hurricanes, floods, heat waves and other major natural disasters, greater attention deserves to be paid to long-term as well as acute cardiovascular consequences,” Steptoe concludes.

SOURCE: Heart, December 15, 2009.