Suicide rates and the association with climate: A population-based study (original) (raw)
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The effect of seasonal changes and climatic factors on suicide attempts of young people
BMC psychiatry, 2017
Seasonal changes and climatic factors like ambient temperature, sunlight duration and rainfall can influence suicidal behavior. This study analyses the relationship between seasonal changes and climatic variations and suicide attempts in 2131 young patients in Istanbul, Turkey. In our study sample, there was an association between suicide attempts in youths and seasonal changes, as suicide attempts occurred most frequently during summer in females as well as in males. Furthermore, there was a positive correlation between the mean temperature over the past 10 days and temperature at the index day and suicide attempts in females. After seasonality effects were mathematically removed, the mean temperature 10 days before a suicide attempt remained significant in males only, indicating a possible short-term influence of temperature on suicide attempts. This study shows an association between suicide attempts of young people and climatic changes, in particular temperature changes as well ...
Seasonal Associations between Weather Conditions and Suicide--Evidence against a Classic Hypothesis
American Journal of Epidemiology, 2006
Psychiatrists, epidemiologists, and sociologists have debated the existence of an association between weather conditions and suicide seasonality since the preliminary statistical investigations in the 19th century. Provided that the effect of weather conditions on suicide operates via a dose-response-like mechanism, time-series (Box-Jenkins) analysis permits an indirect test of the hypothesis that temperature or other weather variables promote higher suicide frequencies in late spring and early summer months. The authors modeled monthly data on suicide and climatic conditions (i.e., temperature, sunshine, and precipitation data) in Switzerland. Cross-correlations between the filtered (prewhitened) residual series were calculated for the period 1881-2000, for consecutive 30-year periods, for different suicide methods, and-with regard to the seasonality hypothesis-for series relying on moving 1-and 3-month frames. Positive cross-correlations emerged between suicide and temperature data for the whole time series, as well as in all consecutive 30-year periods. However, cross-correlations of data series based on moving frames showed a minor peak in associations for summer frames and a major peak in associations for winter frames, the latter reflecting suicides performed mainly outdoors (being run over by a train and jumping from high places). The results represent a novel minor effect in seasonality of suicide, which is hardly compatible with the hypothesized role of temperature in suicide seasonality. models, statistical; seasons; suicide; weather Abbreviation: ARIMA, autoregressive integrated moving average. * ARIMA, autoregressive integrated moving average. y Model (0,0,2)(0,1,2) 12 with similar outcome. z Model (0,0,1)(0,1,1) 12 with similar outcome.
Suicide and Ambient Temperature: A Multi-Country Multi-City Study
Environmental Health Perspectives
BACKGROUND: Previous literature suggests that higher ambient temperature may play a role in increasing the risk of suicide. However, no multicountry study has explored the shape of the association and the role of moderate and extreme heat across different locations. OBJECTIVES: We examined the short-term temperature-suicide relationship using daily time-series data collected for 341 locations in 12 countries for periods ranging from 4 to 40 y. METHODS: We conducted a two-stage meta-analysis. First, we performed location-specific time-stratified case-crossover analyses to examine the temperature-suicide association for each location. Then, we used a multivariate meta-regression to combine the location-specific lag-cumulative nonlinear associations across all locations and by country. RESULTS: A total of 1,320,148 suicides were included in this study. Higher ambient temperature was associated with an increased risk of suicide in general, and we observed a nonlinear association (inverted J-shaped curve) with the highest risk at 27°C. The relative risk (RR) for the highest risk was 1.33 (95% CI: 1.30, 1.36) compared with the risk at the first percentile. Country-specific results showed that the nonlinear associations were more obvious in northeast Asia (Japan, South Korea, and Taiwan). The temperature with the highest risk of suicide ranged from the 87th to 88th percentiles in the northeast Asian countries, whereas this value was the 99th percentile in Western countries (Canada, Spain, Switzerland, the UK, and the United States) and South Africa, where nearly linear associations were estimated. The country-specific RRs ranged from 1.31 (95% CI: 1.19, 1.44) in the United States to 1.65 (95% CI: 1.40, 1.93) in Taiwan, excluding countries where the results were substantially uncertain. DISCUSSION: Our findings showed that the risk of suicide increased with increasing ambient temperature in many countries, but to varying extents and not necessarily linearly. This temperature-suicide association should be interpreted cautiously, and further evidence of the relationship and modifying factors is needed.
Seasonal variation in suicides re-examined: no sex difference in Hong Kong and Taiwan
Acta Psychiatrica Scandinavica, 1997
The seasonal variation in suicides in Hong Kong and Taiwan during the period 1981 to 1993 was examined using harmonic analysis. A single cycle per year with lowest incidence in the winter months was found in both locations and for both sexes. Despite the regional differences in ascertainment procedures and preferred suicide methods, the absence of a biseasonal distribution of female suicides was consistently observed. This finding was contrary to that reported in many Western countries. A nonshared psychosocial process underlying the cross-cultural difference in the seasonality of female suicide is suggested.
Seasonality of Suicidal Behavior
International Journal of Environmental Research and Public Health, 2012
A seasonal suicide peak in spring is highly replicated, but its specific cause is unknown. We reviewed the literature on suicide risk factors which can be associated with seasonal variation of suicide rates, assessing published articles from 1979 to 2011. Such risk factors include environmental determinants, including physical, chemical, and biological factors. We also summarized the influence of potential demographic and clinical characteristics such as age, gender, month of birth, socioeconomic status, methods of prior suicide attempt, and comorbid psychiatric and medical diseases. Comprehensive evaluation of risk factors which could be linked to the seasonal variation in suicide is important, not only to identify the major driving force for the seasonality of suicide, but also could lead to better suicide prevention in general.
Seasonality of suicide: a multi-country multi-community observational study
Epidemiology and Psychiatric Sciences, 2020
Aims We aimed to investigate the heterogeneity of seasonal suicide patterns among multiple geographically, demographically and socioeconomically diverse populations. Methods Weekly time-series data of suicide counts for 354 communities in 12 countries during 1986–2016 were analysed. Two-stage analysis was performed. In the first stage, a generalised linear model, including cyclic splines, was used to estimate seasonal patterns of suicide for each community. In the second stage, the community-specific seasonal patterns were combined for each country using meta-regression. In addition, the community-specific seasonal patterns were regressed onto community-level socioeconomic, demographic and environmental indicators using meta-regression. Results We observed seasonal patterns in suicide, with the counts peaking in spring and declining to a trough in winter in most of the countries. However, the shape of seasonal patterns varied among countries from bimodal to unimodal seasonality. The...
Archives of Suicide Research, 1998
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.
A comparison of seasonal variation between suicide deaths and attempts in Hong Kong SAR
Journal of Affective Disorders, 2004
Background: Seasonal variations in suicide deaths and attempted suicides have been reported for many countries. Recent research has suggested that seasonal patterns of suicide deaths have diminished considerably. The seasonality pattern between attempts and completed ones are not the same. This paper is the first one to examine seasonal variation between suicide deaths and attempts simultaneously. Method: Census and Statistics Department and the Hospital Authority provided mortality and morbidity data on suicides for the period 1997-2001 in Hong Kong SAR, respectively. Seasonal patterns of suicide deaths and attempts were examined by a harmonic analysis and a non-parametric chi-square test. Results: A significant seasonal variation was detected in suicide attempts with a markedly bi-seasonal pattern was found amongst females with a peak in May and October; only a cyclic pattern was observed for males with a peak in summer. The female attempters who used non-violent suicide methods contributed to the second peak in October. On the other hand, there was no evidence of significant differences in the seasonal distribution among the suicide deaths for males and females. Only a mild pattern was found amongst females involving in violent suicide deaths, while others can be treated as a random event and no significantly pattern was observed in our study. Overall, a significant difference in seasonal variation existed between suicide deaths and attempts (p-value < 0.01). Conclusions: This study reinforces the findings that seasonal variation in suicide appears to be diminishing. Also, suicide attempters and completed suicides in Hong Kong seem to arise from two non-identical but overlapping groups in the community.