Short-Term Public Health Impact of the July 22, 2011, Terrorist Attacks in Norway: A Nationwide Register-Based Study.

OBJECTIVES: To examine increases in several health outcomes after the July 22, 2011 terrorist attacks in Norway. METHODS: Retrospective analysis of nationwide registers (n = 4,953,000) where incidences of schizophrenia/psychosis hospitalizations, suicides, acute myocardial infarctions, and preterm births after the terrorist attacks were compared with corresponding periods the previous 3 years. RESULTS: Compared with the same period the preceding 3 years, the observed number of hospitalizations from schizophrenia/psychosis was 14% higher during the first 4 weeks after the terrorist attack (incidence ratio [IR] = 1.14, 95% confidence interval [CI] = 1.07-1.21). The corresponding IRs for the first 3 days and the first week were 1.26 (95% CI = 0.99-1.58) and 1.10 (95% CI = 0.96-1.24). The observed number of suicides was increased by 45% the first 4 weeks (IR = 1.45, 95% CI = 1.12-1.86), 163% the first 3 days (IR = 2.63, 95% CI = 1.15-5.20), and 105% the first week (IR = 2.05, 95% CI = 1.14-3.42). For acute myocardial infarction, there was an increase of 5% the first 4 weeks. There were also more births the 4 weeks (IR = 1.04, 95% CI = 1.01-1.07, but this increase was not seen in preterm births of less than 37 weeks of gestation (IR = 0.93, 95% CI = 0.83-1.04). CONCLUSIONS: We observed a general nationwide increase of health outcomes investigated in this study the first 4 weeks after the terrorist attacks. These results may contribute to the growing body of evidence on the adverse health outcomes that may accompany national stressors.