Objective: To determine if the Niigata-Chuetsu earthquake of October 2004 increased long-term mortality from acute myocardial infarction (AMI).
Design: A comparative study of mortality rates before and after the earthquake, as well as between the disaster and control areas, by analysing death certificate data from 1 October 1999 to 30 September 2007.
Setting: The disaster area and a control area in Niigata Prefecture (n = 2 448 025 in 1 October 2004) in Japan.
Population: The total population of Niigata Prefecture observed for five years (12 333 429 person-years) before and three years (7 279 076 person-years) after the earthquake.
Main outcome measures: Mortality from AMI (ICD-10, I21 and I22).
Results: Overall mortality rates from AMI five years before and three years after the earthquake in the disaster area were 47.3 and 53.9 per 100 000 person-years, respectively. Change (+6.6 or +14.0%) was significantly different (p = 0.0008), compared to the control area, where mortality rates were 42.5 and 42.6 per 100 000 person-years, respectively, and was not significantly different (p = 0.9028). In men, a change in AMI mortality before and after the earthquake in the disaster area was +7.1 per 100 000 person-years (+13.4%, p = 0.0172), and +2.0 (+4.2%, p = 0.2362) in the control area. In women, a change in AMI mortality in the disaster area was +6.2 per 100 000 person-years (+14.9%, p = 0.0184) and −1.6 (−4.2%, p = 0.2735) in the control area.
Conclusions: The Niigata-Chuetsu earthquake significantly increased long-term mortality from AMI in both men and women. Clinicians and policymakers in public health must recognise the need for long-term prevention of AMI in earthquake disaster areas.