Seasons and meteorological factors in suicidal behaviour: Findings and methodological considerations from a Danish study

Abstract

This study is part of a joint venture project carried out by the Centre for Suicidological Research, Odense, and the Danish Meteorological Institute, Copenhagen. The overall purpose of that project is to examine the seasonality of suicidal behaviour and any covariations between suicidal behaviour and the weather in the Scandinavian countries. The project will comprise studies involving parameters such as suicide and attempted suicide, temporal variations including weekdays, holidays, lunar phases. etc., and a variety of meteorological factors. In this article, which presents results from a pilot study based on Danish data (county of Funen), focus is on temporal variations (month, week) and covariations between suicide and meteorological factors and the methodological problems involved. The material comprises all deaths registered as suicides in Funen (appr. 10% of Denmark) in the period 1970-1993, in all 2610 (age 15+). The meteorological data from the same period consists of daily information on precipitation, temperatures, wind velocities, hours of sunlight, etc. The results confirm findings of several previous studies, especially concerning the spring peak and a decreasing tendency throughout the week with significantly fewer suicides on weekends. Our findings indicate that climatological factors, e.g., changing weather, also to some extent might have an impact on suicidal behaviour. Weather may not be a major factor, but it needs, however, to be taken seriously and into account, when considering the etiology of suicide.