The reliability of suicide rates: An analysis of railway suicides from two sources in fifteen European countries

Background: National suicide data are an underestimation of the actual number of suicides but are often assumed to be reliable and useful for scientific research. The aim of this study is to contribute to the discussion of the reliability of suicide mortality data by comparing railway suicides from two data sources.

Methods: Data for the railway suicides and the concurrent causes of death of fifteen European countries were collected from the European Detailed Mortality Database and the European Railway Agency (ERA). Suicide rates, odds ratios and confidence intervals were calculated.

Results: The suicide data from the ERA were significantly higher than the national data for six out of fifteen countries. In three countries, the ERA registered significantly more railway suicides compared to the sum of the national suicides and undetermined deaths. In Italy and France, the ERA statistics recorded significantly more railway related fatalities than the national statistical offices. In total the ERA statistics registered 34% more suicides and 9% more railway fatalities compared with the national statistics.

Limitations: The findings of this study concern railway suicides and they cannot be extrapolated to all types of suicides. Further, the national suicide statistics and the ERA data are not perfectly comparable, due to the different categorisations of the causes of death.

Conclusions: Based on the data for railway suicides, it seems that the underestimation of suicide rates is significant for some countries, and that the degree of underestimation differs substantially among countries. Caution is needed when comparing national suicide rates. There is a need for standardisation of national death registration procedures at the European level. (C) 2010 Elsevier B.V. All rights reserved.