The influence of climate on suicidal behaviour in Italy

The role of meteorological factors in suicide mortality in Wuhu, a humid city along the Yangtze River in Eastern China

As the climate continues to change, suicide is becoming more frequent. In this study, absolute humidity (AH) was included for the first time and Wuhu, a typical subtropical city along the Yangtze River, was taken as the research object to explore the impact of suicide death risk on meteorological factors. The daily meteorological factors and suicide mortality data of Wuhu city from 2014 to 2020 were collected. Guided by structural equation model (SEM), a time series analysis method combining distributed lag nonlinear model (DLNM) and generalized additive model (GAM) was adopted. To investigate the correlation among different populations, we stratified age and gender at different meteorological levels. A total of 1259 suicide deaths were collected in Wuhu. The results indicated that exceedingly low and low levels of AH short-term exposure increased suicide mortality, with the maximum effect occurring at lag 14 for both levels of exposure, when the relative risk (RR) was 1.131 (95% CI: 1.030, 1.242) and 1.065 (95% CI: 1.006, 1.127), respectively. Exposure to exceedingly high and exceedingly low levels of temperature mean (T mean) also increased suicide mortality, with maximum RR values of 1.132 (lag 14, 95% CI: 1.015, 1.263) and 1.203 (lag 0, 95% CI: 1.079, 1.340), sequentially. As for diurnal temperature range (DTR), low-level exposure decreased the risk of suicide, while high-level exposure increased this risk, with RR values of 0.955 (lag 0, 95% CI: 0.920, 0.991, minimum) and 1.060 (lag 0, 95% CI: 1.018, 1.104, maximum), sequentially. Stratified analysis showed that AH and DTR increased the suicide death risk in male and elderly people, while the risk effect of T mean have no effect on young people only. In summary, male and elderly people appear to be more vulnerable to adverse weather effects.

Increase in Search Interest for "Suicide" and "Depression" for Particular Days of the Week and Times of Day: Analysis Based on Google Trends

Depression is the most common disorder in people who attempt suicide or die by suicide. Research review indicate that therapy of depression (including psychoeducation) is one of the main factors in the prevention of suicidal behavior. In this paper we examine the intensification of search interest for the terms "depression" and "suicide" in Google search engine with regard to the time of day and day of the week in Poland, Germany, Great Britain and Italy. The goal of the study was to determine if there are any days of the week or hours when search for "suicide" and "depression" particularly increases. Numerous studies focusing not only on the seasonality of suicidal behavior, but also on the days of the week and hours, indicate that it is most often undertaken on Mondays in the night and early morning hours. The results of the research being the basis of this paper show a certain time coincidence: first, the increase in search interest for "suicide" and "depression" and then undertaking suicidal behavior (suicide and suicide attempts). Searching for terms "suicide" and "depression" usually took place (except in Italy) at weekends and most often in the late evening hours and at night. The conclusions from the research can be used in suicide prevention activities, for example in determining the hours of operation of individual helpline numbers.

Climate rather than economic variables might have caused increase in US homicide but not suicide rates during the Great Depression

BACKGROUND

It is widely believed that during the Great Depression (1929-1933) there was a rise in suicidal rates which was causally related to the increase in unemployment. There are no studies on the effect the Great Depression had on homicidal rates METHODS: The data concerning suicide, homicide, economic and climatic variables for the years 1900-1940 for the whole of the US were gathered from the US Center for Disease Control, the Maddison Project, the National Bureau of Economic Research and the National Climatic Data Center. Time Series Analysis was performed.

RESULTS

The results are inconclusive on the role of economic factors but preclude any role of climate on suicidal rates during the years 1900-1940 in the US. Suicidal rates might have a 24-years periodicity, however much longer time series are needed to confirm this. On the contrary they strongly suggest an effect of higher temperatures on homicidal rates after 1922.

CONCLUSIONS

The results of the current study suggest a direct and clear effect of climate (higher temperatures) on the increasing homicidal rates in the US after 1922 but failed to establish a causal relationship between suicide rates and economic or climate variables. These should be considered together with increasing concerns on the possible effect of climate change on mental health.

Suicide disparities across metropolitan areas in the US: A comparative assessment of socio-environmental factors using a data-driven predictive approach

Disparity in suicide rates across various metropolitan areas in the US is growing. Besides personal genomics and pre-existing mental health conditions affecting individual-level suicidal behaviors, contextual factors are also instrumental in determining region-/community-level suicide risk. However, there is a lack of quantitative approach to model the complex associations and interplays of the socio-environmental factors with the regional suicide rates. In this paper, we propose a holistic data-driven framework to model the associations of socio-environmental factors (demographic, socio-economic, and climate) with the suicide rates, and compare the key socio-environmental determinants of suicides across the large and medium/small metros of the vulnerable US states, leveraging a suite of advanced statistical learning algorithms. We found that random forest outperforms all the other models in terms of both in-sample goodness-of-fit and out-of-sample predictive accuracy, which is then used for statistical inferencing. Overall, our findings show that there is a significant difference in the relationships of socio-environmental factors with the suicide rates across the large and medium/small metropolitan areas of the vulnerable US states. Particularly, suicides in medium/small metros are more sensitive to socio-economic and demographic factors, while that in large metros are more sensitive to climatic factors. Our results also indicate that non-Hispanics, native Hawaiian or Pacific islanders, and adolescents aged 15-29 years, residing in the large metropolitan areas, are more vulnerable to suicides compared to those living in the medium/small metropolitan areas. We also observe that higher temperatures are positively associated with higher suicide rates, with large metros being more sensitive to such association compared to that of the medium/small metros. Our proposed data-driven framework underscores the future opportunities of using big data analytics in analyzing the complex associations of socio-environmental factors and inform policy actions accordingly.

Influence of contextual factors on death by suicide in rural and urban settings

PURPOSE

To examine the association between contextual factors, represented by geographic and community health variables, and suicide among rural and urban Department of Veterans Affairs health care users (VA users).

METHODS

We performed a retrospective cohort study of 12,700,847 VA users between 2003 and 2017. We assigned contextual factors based on individuals' home address at the ZIP Code (area deprivation), county (sunlight exposure, altitude, and community health), and state level (firearm ownership), using publicly available data sources. We grouped contextual factors by quintiles or prespecified thresholds, depending on the nature of each variable. We obtained mortality data from the National Death Index. We measured the effect of living in a place with the highest versus lowest level of each contextual factor on odds of suicide using logistic regression, adjusting for individual compositional factors abstracted from VA electronic medical records data. We used random forest modeling to build prediction models for suicide based on contextual factors among rural and urban veterans.

FINDINGS

Almost all contextual factors we examined were significantly associated with suicide among rural and urban VA users, even after adjusting for individual compositional factors. However, no contextual variables were strong protective or risk factors (0.5<OR>2.0), and prediction models leveraging these contextual factors had poor accuracy among both rural (0.51, 95% CI: 0.48-0.54) and urban (0.53, 95% CI: 0.51-0.55) VA users.

CONCLUSIONS

A wide variety of contextual factors is significantly associated with suicide among rural and urban VA users. However, the factors we measured contributed very little to individual-level suicide risk.

Association between lithium in tap water and suicide mortality rates in Miyazaki Prefecture

Background

Most studies have reported that suicide mortality rates are negatively associated with lithium levels in tap water; however, a few studies showed either no association or a positive association. Thus, the association between suicide mortality and lithium levels in tap water remains controversial. To clarify the association, our study evaluated the association between lithium levels in tap water and suicide mortality rates in Miyazaki Prefecture of Japan, after adjusting for confounding factors.

Methods

We measured lithium levels in tap water across the 26 municipalities of Miyazaki Prefecture in Japan. We examined the standardized mortality ratio (SMR) for suicide in each municipality and used the data as the average suicide SMRs over 5 years (2009–2013). Weighted least-squares regression analysis, adjusted for the size of each municipality’s population, was used to investigate the association between lithium levels in tap water and suicide SMRs. In addition to a crude model, in an adjusted model, potential confounding factors (proportion of elderly people, proportion of one-person households, annual marriage rate, annual mean income, unemployment rate, the density of medical doctors per 100,000 people, annual total rainfall, and proportion of people with a college education or higher) were added as covariates.

Results

We showed that male and female suicide SMRs were not associated with lithium levels in tap water in Miyazaki Prefecture. After adjusting for confounders, male suicide SMRs were significantly and positively associated with the proportion of elderly people in the population and annual total rainfall, and female suicide SMRs were associated with the proportion of elderly people in the population.

Conclusions

No association between lithium levels in tap water and suicide mortality rates was found in Miyazaki Prefecture.

Exploring temporal suicidal behavior patterns on social media: Insight from Twitter analytics

A valid mechanism for suicide detection and intervention to a wider population online has not yet been fully established. With the increasing suicide rate, we proposed an approach that aims to examine temporal patterns of potential suicidal ideations and behaviors on Twitter to better understand their risk factors and time-varying features. It identifies latent suicide topics and then models the suicidal topic-related score time series to quantitatively represent behavior patterns on Twitter. After evaluated on a collection of suicide-related tweets in 2016, 13 key risk factors were discovered and the temporal patterns of suicide behavior on different days during 1 week were identified to highlight the distinct time-varying features related to different risk factors. This study is practical to help public health services and others to develop refined prevention strategies, to monitor and support a population of high-risk at right moments.

Ambient temperature, sunlight duration, and suicide: A systematic review and meta-analysis

BACKGROUND

The relationship between sunlight hours, temperature, and suicide has been investigated in many previous studies, but with inconsistent findings. We conducted this meta-analysis aiming at providing clear evidence about whether sunlight hours and temperature can affect the risk of suicide.

METHODS

Relevant literature published before 7 Jul 2018 was searched in three electronic database of PubMed, Web of science and Cochrane. Between-study heterogeneity in the effect estimates were examined by study design (i.e., exposure time resolution, temperature measure and suicide classification) and population vulnerability (i.e., sex, national income level, climate zone and study location).

RESULTS

Regarding temperature-suicide association, we identified 14 studies that provided 23 effect estimates for meta-analysis. Our random-effects model showed that each 1 °C increase in temperature was significantly associated with a 1% increase in the incidence of suicide (Incidence Rate Radio (IRR) = 1.01; 95%CI = 1.00-1.02; p < 0.05). As for sunlight duration and suicide, 11 effect estimates from 4 studies were pooled using a fixed-effects model. Significant association between sunlight duration (per 1 h increase) and the risk of suicide was not observed, and the pooled IRR was 1.00 (95%CI = 0.99-1.01; p > 0.05). There was significant heterogeneity between previous studies' effect estimates, and significantly lower heterogeneity was noted for the female group, for studies that did analyses at daily scale, and for studies using mean temperature as the exposure indicator.

CONCLUSION

Our findings suggest a significant and positive association between temperature rises and incidence of suicide, and a non-significant association between sunlight duration and incidence of suicide. Populations living in tropical and temperate zones or at middle-income level may be particularly vulnerable to temperature increase.

The effect of altitude and climate on the suicide rates in Turkey

Suicide is one of the most important public health problems. There was an association between suicide and several factors such as psychiatric diseases and psychological characteristics, somatic illness, cultural, socioeconomic, familial, occupational and individual risk factors. Also, high altitude and climatic factors including high temperature, cloudiness, more sunshine and low rainfalls were defined as some of these risk factors in the literature. In this study, we aimed to investigate correlation between suicide rates and altitudes of all cities in Turkey and between suicide rates and climatic factors including Rainfall Activity Index, Winter Mean Temperatures, Summer Mean Temperatures and Temperature Difference between January and July previously defined by several authors in the broad series in Turkey. In Turkey, 29865 suicidal deaths occurred in 10 years period between 2006 and 2015. Of them, 21020 (70.4%) were males and 8845 (29.6%) were females. In this study, we found that high altitude above 1500 m, winter median temperature lower than -10 °C and hard temperature changes above 25 °C between winter and summer of settlements were important factors that affected on female suicide rates appropriate to knowledge which defined in previous studies. In conclusion, we suggested that the associations among suicide rates with altitudes and climate should be studied in wider series obtained from different countries for reaching more reliable results.

[Impact of natural lithium ressources on suicide mortality in Chile 2000-2009: a geographical analysis]

BACKGROUND

There is increasing evidence for the hypothesis that lithium salts at naturally occurring levels in drinking water may have a moderating effect on suicide rates of the exposed population. The aim of this study was to examine whether the lithium rich Atacama region in Chile is associated with lower suicide mortality in comparison to other regions.

METHODS

Suicide data was acquired from the Chilean Ministry of Health. Socio-economic variables (rate of unemployment, urbanity, median household income, percentage of indeginous population) were obtained for all regions of Chile from the national statistical institute. We calculated annual suicide rates per 100,000 for each group for the years 2000-2009 and tested the hypothesis that suicide rates are lower in lithium rich regions in comparison to other regions of Chile.

RESULTS

The lithium rich Atacama Desert shows a significantly lower suicide rate (9.99 per 100,000) in comparison to other parts of Chile (12.50 per 100,000) (t = 4.75, df = 18, p < 0.001).

CONCLUSIONS

Chilean regions rich in naturally occurring lithium salts show lower suicide mortality rates in comparison to other regions. Although causality cannot be proven by this design, these findings add to previous findings and warrant further research on the effects of naturally occurring low-dose lithium on health.

Solar radiation increases suicide rate after adjusting for other climate factors in South Korea

OBJECTIVE

Previous studies have indicated that suicide rates have significant seasonal variations. There is seasonal discordance between temperature and solar radiation due to the monsoon season in South Korea. We investigated the seasonality of suicide and assessed its association with climate variables in South Korea.

METHOD

Suicide rates were obtained from the National Statistical Office of South Korea, and climatic data were obtained from the Korea Meteorological Administration for the period of 1992-2010. We conducted analyses using a generalized additive model (GAM). First, we explored the seasonality of suicide and climate variables such as mean temperature, daily temperature range, solar radiation, and relative humidity. Next, we identified confounding climate variables associated with suicide rate. To estimate the adjusted effect of solar radiation on the suicide rate, we investigated the confounding variables using a multivariable GAM.

RESULTS

Suicide rate showed seasonality with a pattern similar to that of solar radiation. We found that the suicide rate increased 1.008 times when solar radiation increased by 1 MJ/m² after adjusting for other confounding climate factors (P < 0.001).

CONCLUSION

Solar radiation has a significant linear relationship with suicide after adjusting for region, other climate variables, and time trends.

Climate change but not unemployment explains the changing suicidality in Thessaloniki Greece (2000-2012)

INTRODUCTION

Recently there was a debate concerning the etiology behind attempts and completed suicides. The aim of the current study was to search for possible correlations between the rates of attempted and completed suicide and climate variables and regional unemployment per year in the county of Thessaloniki, Macedonia, northern Greece, for the years 2000-12.

MATERIAL AND METHODS

The regional rates of suicide and attempted suicide as well as regional unemployment were available from previous publications of the authors. The climate variables were calculated from the daily E-OBS gridded dataset which is based on observational data

RESULTS

Only the male suicide rates correlate significantly with high mean annual temperature but not with unemployment. The multiple linear regression analysis results suggest that temperature is the only variable that determines male suicides and explains 51% of their variance. Unemployment fails to contribute significantly to the model. There seems to be a seasonal distribution for attempts with mean rates being higher for the period from May to October and the rates clearly correlate with temperature. The highest mean rates were observed during May and August and the lowest during December and February. Multiple linear regression analysis suggests that temperature also determines the female attempts rate although the explained variable is significant but very low (3-5%)

CONCLUSION

Climate variables and specifically high temperature correlate both with suicide and attempted suicide rates but with a different way between males and females. The climate effect was stronger than the effect of unemployment.

Relationship of suicide rates with climate and economic variables in Europe during 2000-2012

BACKGROUND

It is well known that suicidal rates vary considerably among European countries and the reasons for this are unknown, although several theories have been proposed. The effect of economic variables has been extensively studied but not that of climate.

METHODS

Data from 29 European countries covering the years 2000-2012 and concerning male and female standardized suicidal rates (according to WHO), economic variables (according World Bank) and climate variables were gathered. The statistical analysis included cluster and principal component analysis and categorical regression.

RESULTS

The derived models explained 62.4 % of the variability of male suicidal rates. Economic variables alone explained 26.9 % and climate variables 37.6 %. For females, the respective figures were 41.7, 11.5 and 28.1 %. Male suicides correlated with high unemployment rate in the frame of high growth rate and high inflation and low GDP per capita, while female suicides correlated negatively with inflation. Both male and female suicides correlated with low temperature.

DISCUSSION

The current study reports that the climatic effect (cold climate) is stronger than the economic one, but both are present. It seems that in Europe suicidality follows the climate/temperature cline which interestingly is not from south to north but from south to north-east. This raises concerns that climate change could lead to an increase in suicide rates. The current study is essentially the first successful attempt to explain the differences across countries in Europe; however, it is an observational analysis based on aggregate data and thus there is a lack of control for confounders.

Trace lithium is inversely associated with male suicide after adjustment of climatic factors

BACKGROUND

Previously, we showed the inverse association between lithium in drinking water and male suicide in Kyushu Island. The narrow variation in meteorological factors of Kyushu Island and a considerable amount of evidence regarding the role of the factors on suicide provoked the necessities of adjusting the association by the wide variation in sunshine, temperature, rain fall, and snow fall.

METHODS

To keep the wide variation in meteorological factors, we combined the data of Kyushu (the southernmost city is Itoman, 26°) and Hokkaido (the northernmost city is Wakkanai, 45°). Multiple regression analyses were used to predict suicide SMRs (total, male and female) by lithium levels in drinking water and meteorological factors.

RESULTS

After adjustment of meteorological factors, lithium levels were significantly and inversely associated with male suicide SMRs, but not with total or female suicide SMRs, across the 153 cities of Hokkaido and Kyushu Islands. Moreover, annual total sunshine and annual mean temperature were significantly and inversely associated with male suicide SMRs whereas annual total rainfall was significantly and directly associated with male suicide SMRs.

LIMITATIONS

The limitations of the present study include the lack of data relevant to lithium levels in food and the proportion of the population who drank tap water and their consumption habits.

CONCLUSIONS

The present findings suggest that trace lithium is inversely associated with male but not female suicide after adjustment of meteorological factors.

Associations between climate variability, unemployment and suicide in Australia: a multicity study

BACKGROUND

A number of studies have examined the associations of suicide with meteorological variables (MVs) and socioeconomic status but the results are inconsistent. This study assessed whether MVs and unemployment were associated with suicide in eight Australian capital cities.

METHODS

Data on suicide, population and unemployment rate (UER) between 1985 and 2005 were from the Australian Bureau of Statistics. MVs was provided by Australian Bureau of Meteorology. A generalized linear regression model with Poisson link was applied to explore the association of suicide with MVs and UER.

RESULTS

Temperature difference (ΔT, the difference in mean temperature between current month and previous one month) was positively associated with suicide in Sydney, Melbourne, Brisbane and Hobart. There was also a significant and positive association between UER and suicide in Sydney, Melbourne, Brisbane and Perth. MVs had more significant associations with violent suicide than that of non-violent suicide. There were no consistent associations between other MVs and suicide. A significant interaction between ΔT and UER on suicide was found in Sydney, Melbourne and Brisbane, such that increased temperature amplified the magnitude of the association between UER and suicide.

CONCLUSIONS

ΔT and UER appeared to jointly influence the occurrence of suicide in Australian capital cities. This finding may have implications for developing effective suicide prevention strategies.

Does diurnal temperature range influence seasonal suicide mortality? Assessment of daily data of the Helsinki metropolitan area from 1973 to 2010

Several studies show a peak in suicide rates during springtime and suggest differences in the seasonal variation of suicides. However, the seasonal distribution of the temperature impact on suicide is less clear. This study investigated the relationship between diurnal temperature range (DTR) on suicide mortality. Daily temperature and suicide data for Helsinki were analyzed for the period of 1973-2010 inclusive. Overall, DTR reached its maximum during the spring from mid-April to mid-June, which is also the season with highest suicide mortality in the study region. Specifically, the seasonal timing and maxima for both DTR and suicides vary from year to year. Time series analysis of DTR and suicide records revealed a significant (P<0.01) correlation between the springtime DTR maxima and suicide rates for males. No similar association could be found for females. These results provide evidence that a higher springtime DTR could be linked statistically to a higher seasonal suicide rate each spring, whereas the exact timing of the DTR peak did not associate with the seasonal suicide rate. A possible mechanism behind the springtime association between the DTR and suicides originates from brown adipose tissue (BAT) over-activity. Activation of BAT through the winter improves cold tolerance at the cost of heat tolerance. This might trigger anxiety and psychomotor agitation, affecting mood in a negative way. As a hypothesis, the compromised heat tolerance is suggested to increase the risk of death from suicide.

Seasonality of self-destructive behaviour: seasonal variations in demographic and suicidal characteristics in Van, Turkey

OBJECTIVE

Seasonality is one of the most interesting but still elusive issue in suicide research. Linkages of seasonality in suicides to possible contributors such as gender, type of method used, and climatic factors have received attention in different cultures. We aimed at evaluating seasonal trends in suicidal behaviour according to demographic characteristics, reasons for self-destructive behaviour and means preferred in suicide.

METHODS

Our aim was to assess the seasonal variation in self-destructive behaviour in terms of completed and attempted suicides in a 3-year time period from 2008 to 2010 in Van, Turkey. A total of 1448 cases were registered over a 3-year time period in the city. Seasonal deviations in demographic characteristics, reasons for suicide, and methods of suicide were evaluated.

RESULTS

Seasonal distribution of both completed and attempted suicides by gender did not significantly deviate. On the other hand, we found a significant decline in self-destructive behaviours among those who were single and student in the spring. We found a peak in self-destructive behaviours in the autumn among Individuals who suffer from psychological problems.

CONCLUSIONS

Subjects with psychological difficulties were more prone to commit suicide in autumn. Seasonal differences in methods of suicide used by suicidal subjects were not significant.

Temperature-associated suicide mortality: contrasting roles of climatic warming and the suicide prevention program in Finland

OBJECTIVES

Suicide is a notable cause of death worldwide, and while suicidal behavior appears to be associated with variations in temperature, no estimations are available of climate change impacts on suicide rates. The study aims to evaluate the influence of temperature on suicide mortality, especially on multi-decadal and longer time scales, that is, at scales on which the ongoing warming distinctly operates and is correspondingly appropriate for the current policy responses to warming climate.

METHODS

Our results are based on an extraordinarily long record of deaths from suicide in Finland from 1751 to 2008, and a similarly long climatic record of ambient temperatures correlative of environmental change in the study region.

RESULTS

We show that temperature variability explains more than 60 % of the total suicide variance up until the initiation of a national suicide prevention program. Despite ongoing warming, suicide rates have declined since the initiation of the program.

CONCLUSION

By understanding the complexity of suicidal behavior as a response to ambient warming and the observed effects of interventions, our results underline the pressing need for a network of prevention programs to battle against temperature-mediated health hazards.

Low vitamin D status and suicide: a case-control study of active duty military service members

Objective

Considering that epidemiological studies show that suicide rates in many countries are highest in the spring when vitamin D status is lowest, and that low vitamin D status can affect brain function, we sought to evaluate if a low level of 25-hydroxyvitamin D [25(OH)D] could be a predisposing factor for suicide.

Method

We conducted a prospective, nested, case-control study using serum samples stored in the Department of Defense Serum Repository. Participants were previously deployed active duty US military personnel (2002–2008) who had a recent archived serum sample available for analysis. Vitamin D status was estimated by measuring 25(OH) D levels in serum samples drawn within 24 months of the suicide. Each verified suicide case (n = 495) was matched to a control (n = 495) by rank, age and sex. We calculated odds ratio of suicide associated with categorical levels (octiles) of 25(OH) D, adjusted by season of serum collection.

Findings

More than 30% of all subjects had 25(OH)D values below 20 ng/mL. Although mean serum 25(OH)D concentrations did not differ between suicide cases and controls, risk estimates indicated that subjects in the lowest octile of season-adjusted 25(OH)D (<15.5 ng/mL) had the highest risk of suicide, with subjects in the subsequent higher octiles showing approximately the same level of decreased risk (combined odds ratio compared to lowest octile  = 0.49; 95% C.I.: 0.315–0.768).

Conclusions

Low vitamin D status is common in active duty service members. The lowest 25(OH)D levels are associated with an increased risk for suicide. Future studies could determine if additional sunlight exposure and vitamin D supplementation might reduce suicide by increasing 25(OH) D levels.

Atmospheric pressure and suicide attempts in Helsinki, Finland

The influence of weather on mood and mental health is commonly debated. Furthermore, studies concerning weather and suicidal behavior have given inconsistent results. Our aim was to see if daily weather changes associate with the number of suicide attempts in Finland. All suicide attempts treated in the hospitals in Helsinki, Finland, during two separate periods, 8 years apart, were included. Altogether, 3,945 suicide attempts were compared with daily weather parameters and analyzed with a Poisson regression. We found that daily atmospheric pressure correlated statistically significantly with the number of suicide attempts, and for men the correlation was negative. Taking into account the seasonal normal value during the period 1971-2000, daily temperature, global solar radiation and precipitation did not associate with the number of suicide attempts on a statistically significant level in our study. We concluded that daily atmospheric pressure may have an impact on suicidal behavior, especially on suicide attempts of men by violent methods (P < 0.001), and may explain the clustering of suicide attempts. Men seem to be more vulnerable to attempt suicide under low atmospheric pressure and women under high atmospheric pressure. We show only statistical correlations, which leaves the exact mechanisms of interaction between weather and suicidal behavior open. However, suicidal behavior should be assessed from the point of view of weather in addition to psychiatric and social aspects.

Possible effects of changes in the meteorological state over semi-arid areas on the general well-being of weather-sensitive patients

BACKGROUND

The influence of the changes in atmospheric states, typical for areas close to big deserts, on general well-being of hypertensive persons was analyzed.

METHODS

Under test was the group of 20 hypertensive weather-sensitive patients; their blood pressure, pulse rate and appearance of 4 symptoms of discomfort sensations: arthritic pain, unjustified anxiety, severe headache and inexplicable tiredness- were registered. Symptoms are classified in ICD-9 code (780-790) and scored on a 4-point scale. Results were defined as positive (no departure from the range of normal values) or problematic; the daily number of the latter results was collected under the name "pathological reactions" NPR if at least two of these 7 checked symptoms (of one patient) were outside the normal range. Comparison of the current weather conditions with their means, questioning of patients and repeated examinations are used to gain information. The data was analyzed employing the SAS statistical software. Pearson and Spearman correlations were used, applied on the best and worst days, when a minimum and a maximum of pathological changes NPR in the patients' well-being were observed. The statistical significance was p < 0.05 in all cases.

RESULTS

~1500 medical observations and verbal statements were registered in the Primary Care Clinic (Be'er-Sheva, Israel) during 2001-2002. No meaning correlation was found between NPR and absolute values of temperature, humidity and atmospheric pressure. Variations in wind speed WS and direction were expressed in blood pressure changes and in exacerbation of discomfort of various degrees. Unfavorable conditions correspond to days with dominant desert air streams and to high WS, when NPR reaches 85.7%; during the days with prevalent sea breeze NPR was ≤22.9%. The role of wind direction in NPR occurrence is prevalent when WS > 4 m·s-1. The Spearman test gives higher correlation than Pearson test (ρ ~ 0.14, p < 0.03 against ρ ~ 0.1, p < 0.04).

CONCLUSIONS

NPR is more affected by the air streams than by absolute values of meteorological parameters. The method of this study might give to family doctors some additional tools to predict deterioration in general feelings of chronic patients and could be related to other health problems influenced by the meteorological environment.

Temperature change dominates the suicidal seasonality in Taiwan: a time-series analysis

OBJECTIVE

The arguments between bioclimatic and sociodemographic hypotheses for the suicidal seasonality continue. The present study aimed to examine the relationships between suicidal seasonality and the climate as well as the economic factors.

METHODS

The monthly suicide death rates of the total, male and female populations in Taiwan during January 1991-December 2010 were obtained from the population-based database. Autoregressive integrated moving average (ARIMA)/seasonal ARIMA (SARIMA) was used to analyze suicidal seasonality, with monthly ambient temperature, temperature increase, rainfall, sunlight, unemployment and labor force participation rates as the independent inputs.

RESULTS

The models revealed that monthly temperature increase was strongly positively associated with seasonality of suicide rates of all populations (β=0.0184, P<0.001; β=0.0234, P=0.001; β=0.0145, P<0.001, respectively). Rainfall was significantly negatively associated with the total and male suicide rates (β=-0.0001, P=0.012; β=-0.0002, P=0.043, respectively), but not with female. Unemployment and labor force participation rates were not significantly related to their corresponding suicide rates.

LIMITATIONS

Socio-demographic data, individual major events, and subgroups by suicide methods were not taken into account.

CONCLUSIONS

The results indicate that, as far as suicidal seasonality is concerned, monthly temperature increase is the most influential factor, and climatic factors have more significant effect than the economic factors.

Description and validation of a questionnaire for the detection of meteoropathy and meteorosensitivity: the METEO-Q

BACKGROUND

There is a growing interest for the effects of weather changes on both healthy and psychiatric individuals. This study aims to validate a short questionnaire (METEO-Q) for the detection of meteoropathy and meteorosensitivity.

METHODS

The METEO-Q was administered to 1099 (528 men, 571 women) healthy subjects. Factor analyses, internal consistency, and item analysis were undertaken to examine the factorial structure of the questionnaire.

RESULTS

The METEO-Q has satisfactory factorial structure and internal reliability. Our results demonstrate that women have higher scores than man and, therefore, women mostly have meteoropathy.

CONCLUSIONS

Our findings support the use of the METEO-Q for collecting information regarding the effects of weather changes on healthy subjects and potentially on psychiatric patients.

The influence of several changes in atmospheric states over semi-arid areas on the incidence of mental health disorders

The incidence of suicide attempts [Deliberate Self Harm (DSH); ICD-10: X60-X84] and psychotic attacks (PsA; ICD-10, F20-F29) in association with atmospheric states, typical for areas close to big deserts, was analyzed. A retrospective study is based on the 4,325 cases of DSH and PsA registered in the Mental Health Center (MHC) of Ben-Gurion University (Be'er-Sheva, Israel) during 2001-2003. Pearson and Spearman test correlations were used; the statistical significance was tested at p < 0.1. The influence of temperature and humidity on suicide attempts (N(SU)) and psychotic attacks (N(PS)) was weakly pronounced (p > 0.1). Correlation coefficients between N(SU) and N(PS) and speed WS of westerly wind reaches 0.3 (p < 0.05), while their dependence on easterly WS was weaker (p > 0.09). Variations in easterly wind direction WD influence N(SU) and N(PS) values (p < 0.04), but no corresponding correlation with westerly winds was found (p > 0.3). Obviously ,in transition areas located between different regions ,the main role of air streams in meteorological-biological impact can scarcely be exaggerated. An unstable balance in the internal state of a weather-sensitive person is disturbed when the atmospheric state is changed by specific desert winds, which can provoke significant perturbations in meteorological parameters. Results indicate the importance of wind direction, defining mainly the atmospheric situation in semi-arid areas: changes in direction of the easterly wind influence N(SU) and N(PS), while changes in WS are important for mental health under westerly air streams. Obviously, N(SU) and N(PS) are more affected by the disturbance of weather from its normal state, for a given season, to which the local population is accustomed, than by absolute values of meteorological parameters.

Socioeconomic factors outweigh climate in the regional difference of suicide death rate in Taiwan

The present study explored both socioeconomic and climatic factors to obtain a more comprehensive view of the asymmetric regional suicide death rate during 1998-2006 in Taiwan. The annual suicide death rate, population and meteorological data from 19 cities/counties in Taiwan were analysed by multiple regression. Five socioeconomic (sex ratio, no spouse, aged, unemployment and low income) and three climatic (temperature, rainfall and sunshine) factors were identified as significant, explaining 59.0% of the variance in the total suicide death rate. 'Without spouse' and 'aged' were associated with the highest risk, while 'low income with financial aids' was strongly protective. The most influential climatic factor was 'temperature,' which was negatively correlated with suicide. 'Sunshine' was positively associated with suicide. The socioeconomic and climatic factors contributed 52.7% and 6.8%, respectively, to the variance of the total suicide death rate. Limitations of the study included the fact that no individual events were considered, the study was of relatively short duration and it was confined to the territory of Taiwan. Socioeconomic factors outweighed climatic factors in explaining regional differences in the suicide death rate in Taiwan. Temperature weighed more than sunshine. 'Thermotherapy' seems more clinically relevant than the popular light therapy, at least in Taiwan.

Seasonality in suicide--a review and search of new concepts for explaining the heterogeneous phenomena

Seasonality is one of the oldest and most resistant-to-elucidation issues in suicide research. However, in recent years epidemiological research has yielded new results, which provide new perspectives on the matter. This qualitative review summarizes research published since the 1990 s. In particular, the focus is on studies dealing with the historical change of seasonality, cross-sectional comparisons including method-specific diversity, and the association with weather variables and other putative covariates. Recent research has shown that in Western countries the seasonality of suicide is tending to diminish and may, eventually, disappear. It can no longer be considered a universal and homogeneous phenomenon. In addition, different major seasonal cycles have now been determined which mainly depend on different suicide methods. Just as in the epidemiology of suicide methods, the (seasonal) availability and perceived adequacy of methods emerge as the major driving force beyond the seasonal phenomena in suicide.

Notes on the Determinants of Suicide Rates in Italy's Regions: A Reply to Voracek (2009)

This article is a review of Voracek's report (2009) of aggregate intelligence and suicide rates in Italy's regions, contending some findings and proposing new evidence and suggestions for further research. Voracek did not use intelligence data, but educational attainment, which in Italy's regions is affected by sharp imbalances in the quality of public schools and may not reflect differences in intelligence. The statistical analyses were inadequate given the small number of cases; the resulting correlation could be meaningless or even misleading. The paper shows that when the analysis is extended to other variables (latitude) or historical periods (1911) the correlations reported by Voracek are not significant. This criticism is based on perspectives among different branches of psychology and cognitive sciences, economic and social history, and economic geography.

Completed suicide and marital status according to the Italian region of origin

Completed suicide is associated with marital status; being unmarried is associated with a higher suicide rate as compared with being married or living with a partner. Moreover, the region of origin may be particularly important when trying to explain major inequalities in suicide rates across a country. Data were obtained from the Italian Database on Mortality, collected by the Italian Census Bureau (ISTAT) and processed by the Italian National Institute of Health-Statistics Unit. The Italian population in the last Italian census (October 2001) was used to estimate age-standardized mortality rates from suicide by marital status (ICD-9 revision: E950-959) and "natural" causes (ICD-9 revision: 0-280; 320-799). Rate Ratios and 95% confidence intervals were calculated using married individuals as a reference. All analyses were conducted separately for men and women for 2000-2002, the most recent years with data available. Logistic regression analysis was used to compare differences by marital status for suicide versus death from natural causes. There are major inequalities in suicide rates in Italy. The North region has the highest suicide rates both for married and non-married individuals. Sardinia Island has the highest male suicide rate in Italy-23.07 per 100,000 per year-compared with the average national male suicide rate of 13.80, a difference which is significantly higher by 67% (RR: 1.67; 95%CI = 1.40-1.99). In contrast, Sardinia has one of the lowest female suicide rates among the Italian regions, close to that of the South and the Center regions. The North-East is the only region where the suicide rate among divorced men is significantly higher than that of married men. In the South, widowers have the highest suicide rate, with a rate 6-times that of married men (RR = 5.66; 95%CI = 4.46-7.18). Major inequalities in suicide rates by region may derive from different socio-cultural backgrounds, confirming the notion that suicide is a multifaceted phenomenon. The results of the present study indicate that suicide prevention must take into account the social and cultural characteristics of different communities. Moreover, these findings support the notion that marital status may play a central role in influencing suicide.

Suicide mortality in Italy from 1980 to 2002

The aim of this study is to update age and sex mortality rates for suicide in Italy; to evaluate the methods of suicide; to consider the effect of under-reporting on mortality rate for suicide; to compare age-adjusted mortality rates for suicide; and to examine some possible causes for the misclassification of suicide. Temporal trends, from 1980 to 2002, were analyzed using joinpoint regression. Suicide rates decreased from 1980 to 2002 by 10.5% for men and by 44% for women. The change in suicide methods indicated an increasing use of highly lethal methods. The under-reporting of suicide seems to have no effect on temporal changes in mortality rates or on the geographical distribution. These data indicate that Italy is a country at low risk for suicide.

Regional Intelligence and Suicide Rate in Italy

Replicating the majority finding from prior related studies of European countries, regional IQ estimates and suicide rates in Italy were positively correlated; the association was retained with application of controls for regional affluence. Directions for further inquiry into aggregate-level associations of cognitive-ability indicators and suicide risk within nations are discussed.

Preliminary spatiotemporal analysis of the association between socio-environmental factors and suicide

BACKGROUND

The seasonality of suicide has long been recognised. However, little is known about the relative importance of socio-environmental factors in the occurrence of suicide in different geographical areas. This study examined the association of climate, socioeconomic and demographic factors with suicide in Queensland, Australia, using a spatiotemporal approach.

METHODS

Seasonal data on suicide, demographic variables and socioeconomic indexes for areas in each Local Government Area (LGA) between 1999 and 2003 were acquired from the Australian Bureau of Statistics. Climate data were supplied by the Australian Bureau of Meteorology. A multivariable generalized estimating equation model was used to examine the impact of socio-environmental factors on suicide.

RESULTS

The preliminary data analyses show that far north Queensland had the highest suicide incidence (e.g., Cook and Mornington Shires), while the south-western areas had the lowest incidence (e.g., Barcoo and Bauhinia Shires) in all the seasons. Maximum temperature, unemployment rate, the proportion of Indigenous population and the proportion of population with low individual income were statistically significantly and positively associated with suicide. There were weaker but not significant associations for other variables.

CONCLUSION

Maximum temperature, the proportion of Indigenous population and unemployment rate appeared to be major determinants of suicide at a LGA level in Queensland.

Seasonal Variation of Suicide in Brazil

Most of what is known about the seasonal variation in suicide rate originates from studies conducted in the northern hemisphere; very few studies have been done in the southern hemisphere. The purpose of the present study was to explore the possibility that in Brazil, the seasonal variation of suicides is a function of photoperiod. This was accomplished by analyzing monthly suicide data for a 12 yr period (1979 to 1990), within latitudes ranging from 2 degrees N to 33 degrees S. Single cosinor analyses with periods of 12 or 6 months were applied to time series of monthly total and suicidal deaths, separated by gender and state. Significant spring or early summer peaks of suicide were found only in the south of Brazil for both men and women, except for the latter in one state. These peaks did not coincide with those found for total deaths, which occurred in the autumn or winter in all areas. No significant six-month period was found. In the present study, the chance of a suicide was typically 10-17% higher during the peak period than during the other months of the year. Although this moderate seasonal effect might not be sufficient to justify planning large scale prophylactic interventions, those dealing with patients who have suicide ideation should be aware of this high risk time.

[Temporal dimensions of suicide: hypothesis]

In this article, the author examines the temporal dimensions of suicide by taking into account the multiple existing approaches-circadian physiology, psychiatric or sociological epidemiology of suicide-however promoting a socio-anthropological perspective. From this perspective, suicide is examined as a social phenomenon inscribed in time. By beginning with a concern that is characteristic of anthropology of time, knowingly the relation between time of nature and time of society, the author addresses a key issue of the study of suicide already elaborated by Durkheim, in the relation between change that is a basic expression of the passage of time and suicide. After presenting different scientific contributions on the subject, the author proposes an hypothesis allowing integration of the influence of time related to natural phenomenon (cosmobiological rhythms) and the relation of time to social phenomenon (politico-economic rhythms) in relation with suicide and this, according to Gabennesch's theory of "failed promises."

Climate impact on suicide rates in Finland from 1971 to 2003

Seasonal patterns of death from suicide are well-documented and have been attributed to climatic factors such as solar radiation and ambient temperature. However, studies on the impact of weather and climate on suicide are not consistent, and conflicting data have been reported. In this study, we performed a correlation analysis between nationwide suicide rates and weather variables in Finland during the period 1971-2003. The weather parameters studied were global solar radiation, temperature and precipitation, and a range of time spans from 1 month to 1 year were used in order to elucidate the dose-response relationship, if any, between weather variables and suicide. Single and multiple linear regression models show weak associations using 1-month and 3-month time spans, but robust associations using a 12-month time span. Cumulative global solar radiation had the best explanatory power, while average temperature and cumulative precipitation had only a minor impact on suicide rates. Our results demonstrate that winters with low global radiation may increase the risk of suicide. The best correlation found was for the 5-month period from November to March; the inter-annual variability in the cumulative global radiation for that period explained 40 % of the variation in the male suicide rate and 14 % of the variation in the female suicide rate, both at a statistically significant level. Long-term variations in global radiation may also explain, in part, the observed increasing trend in the suicide rate until 1990 and the decreasing trend since then in Finland.

The Seasonal Risk for Deliberate Self-Harm

Groups at seasonal risk for deliberate self-harm (DSH) vary according to their geographic location. It is unknown, however, if seasonal risk factors for DSH are associated with place of birth or place of residence as these are confounded in all studies to date. In order to disaggregate place of birth from place of residence we examined general and seasonal risk factors for DSH in three different population birth groups living in Western Australia: Australian Aborigines, Australian born non-Aborigines, and UK migrants. We found Aborigines are at much higher general risk for DSH than non-Aborigines, but are not at seasonal risk, whereas non-Aboriginal Australians and UK migrants are. For UK migrants, this is only found for females. For all groups at seasonal risk this peaks during the austral (southern hemisphere) spring/summer. Furthermore, non-Aboriginal Australians and UK migrants show a consistent pattern of increased case fatality with increasing age. In contrast, case fatality does not increase with age among Australian Aborigines. Overall, despite living in the same environment, the three birth groups show different patterns of seasonal risk for DSH. In particular, the sex difference found between UK migrants and non-Aboriginal Australian birth groups suggests that predisposition toward seasonal risk for DSH is established early in life, but when present this is expressed according to local conditions.

Climatic factors and bipolar affective disorder

In bipolar disorder, the factors provoking a new episode are unknown. As a seasonal variation has been noticed, it has been suggested that weather conditions may play a role. The aim of the study was to elucidate whether meteorological parameters influence the development of new bipolar phases. A group of patients with at least three previous hospitalizations for bipolar disorder was examined every 3 months for up to 3 years. At each examination an evaluation of the affective phase was made according to the Hamilton Depression Scale (HAM-D(17)), and the Bech-Rafaelsen Mania Rating Scale (MAS). In the same period, daily recordings from the Danish Meteorological Institute were received. We found no correlations between onset of bipolar episodes [defined as MAS score of 11 or more (mania) and as HAM-D(17) score of 12 or more (depression)] and any meteorological parameters. We found a statistical significant correlation between mean HAM-D(17) scores and change in mean and maximum temperature, and non-statistical significant correlations between mean MAS scores and rainfall plus atmospheric pressure, and non-statistical significant correlations between mean HAM-D(17) scores and hours of sunshine and cloudiness. Though meteorological factors may have an impact on triggering new episodes in bipolar patients, they do not constitute a dominant cause.

Prevalence of suicide ideation, plans, and attempts and related risk factors in Italy: results from the European Study on the Epidemiology of Mental Disorders--World Mental Health study

BACKGROUND

As in other Mediterranean countries, suicide mortality rates in Italy are generally lower than they are in Northern and Central European countries and on other continents (eg, North America, Australia). Yet, no studies to date have examined the prevalence of and risk factors for suicide ideation, plans, and attempts, in the general population in Italy.

METHODS

Suicide ideation, plans, and attempts and potential risk factors were assessed in a community survey conducted with 4712 adult respondents (response rate, 71.2%). The participants had been selected from Italian municipality resident registries and made up a stratified, multistage, clustered probability sample. The project was part of the World Health Organization World Mental Health (WMH) Survey Initiative.

RESULTS

The lifetime prevalence (SE) of suicide ideation, plans, and attempts was 3.0% (0.3), 0.7% (0.1), and 0.5% (0.1), respectively. Prevalence rates of these suicide-related phenomena did not differ by Italian geographic macro-area (Northern, Central, and Southern Italy, including the islands of Sicily and Sardinia). Among ideators, the probability of ever making a plan was 24.6% (4.0) and attempt was 18.2% (4.5). The probability of making an attempt for ideators having made a suicide plan was nearly 50%. Risk factors for lifetime suicide-related phenomena were female sex, younger cohort, fewer years of education, and earlier onset age of suicide ideation. The presence of a common mental disorder, especially if comorbid, was associated with a significantly increased risk for all suicide phenomena investigated (ideation, plans, and attempts suicide). There were no substantial differences in the frequency of these phenomena among the 3 main macro-areas examined, that is, Northern, Central, and Southern Italy (including Sicily and Sardinia), which conversely show marked climate, socioeconomic, and cultural differences.

CONCLUSION

As shown in previous studies examining suicide, suicide continuum phenomena (in terms of ideation, plans, and attempt) in Italy were lower than typically observed for other European countries and did not differ for different macro-areas presenting remarkably different socioeconomic conditions. Prevalence rates of common mental disorders were equally lower in Italy than in other European countries. Although the detection of mental disorders represents an important step in suicide prevention, the correlations observed between various suicidal continuum manifestations suggest that timely recognition of suicide ideation and plans is an equally crucial factor in the implementation of effective preventive policies.

Rural/urban differences in the distribution of eating disorder symptoms among adolescents from community samples

OBJECTIVE

Rural/urban differences in the prevalence of mental disorders have often been reported in the last 30 years, among others in the distribution of eating disorder symptoms and suicide rates. The role of sex, age and socioeconomic status in the differences by place of residence has often been neglected in past studies.

METHOD

Two independent community samples of students (mean age=17.4 years, SD=1.4), taken from among those attending high school in an urban district (Cagliari; n=817) and in a rural one (Carbonia; n=507) of south Sardinia, Italy, were invited to fill in the Eating Attitudes Test (EAT), the Bulimic Investigatory Test of Edinburgh (BITE), the Body Attitudes Test (BAT) and the revised Hopkins Symptom checklist (SCL-90-R).

RESULTS

Female students scored higher than male students on all inventories. In male participants, the scores on the EAT were higher in the urban than in the rural sample. Conversely, in both male and female students the rural sample reported higher scores on the BITE symptoms subscale. When the comparison was confined to the fraction of those who scored higher than the suggested cut-off on the EAT and the BITE, students in the urban sample outnumbered those in the rural sample. No other differences were found. Socioeconomic status and age did not influence the differences in the reporting of eating disorder symptoms by place of residence.

CONCLUSIONS

Although caution is required when reading the findings drawn from self-report instruments, it is evident that the factors influencing the distribution of eating disorder symptoms and their psychological correlates by place of residence are far more complex than currently thought.

Seasonal variation in suicidal deaths in Chile: its relationship to latitude

BACKGROUND

Studies in the northern and southern hemispheres consistently identified seasonal influences on monthly and semester suicide distribution. The variations of sunlight exposure in zones of increasing latitude has been suggested as one of the most plausible explanations for this phenomenon. Some recent studies in the northern hemisphere could not find seasonal asymmetries of suicides. The current study examines the monthly, seasonal and semester distribution of suicidal deaths in Chile and the influence of seasons in zones of low latitude as compared with regions of high or very high latitude, trying to determine if a seasonal pattern still exists in a country of the southern hemisphere.

METHODS

Monthly, seasonal and semester suicidal data over the period 1995-1999 were examined for the whole sample and for gender-specific subgroups in Chile. Four different latitudinal zones were analyzed separately, in order to investigate the effect of the photoperiod on suicide distribution. Results were analyzed by chi(2) tests for multinomials, as an overall measure of deviation.

RESULTS

We found a significant unimodal springtime peak for both genders in the global territory. Among the 4,710 male and 829 female suicides reported in this period there were no gender differences in the seasonal pattern of suicidal deaths. When divided into four different latitudinal zones, the regions with low latitude (north of the country) showed no significant differences, while central and southern zones (higher latitude) show a significant springtime pattern. In the extreme south of the country, no significant differences were found, probably due to the very small number of cases.

CONCLUSION

The study confirms the existence of a unimodal springtime peak of suicides in Chile, but not in the zone of low latitude. Results support the notion that the seasonal impact on suicidal distribution is a function of photoperiod.

Inter-annual rainfall variations and suicide in New South Wales, Australia, 1964-2001

The suicide rate in New South Wales is shown to be related to annual precipitation, supporting a widespread and long-held assumption that drought in Australia increases the likelihood of suicide. The relationship, although statistically significant, is not especially strong and is confounded by strong, long-term variations in the suicide rate not related to precipitation variations. A decrease in precipitation of about 300 mm would lead to an increase in the suicide rate of approximately 8% of the long-term mean suicide rate.

Exploring lag and duration effect of sunshine in triggering suicide

BACKGROUND

Sunshine is considered to have a beneficial impact on mood. Interestingly, it has been consistently found that the incidence of suicide reaches a peak during early summer.

METHODS

In order to explore the pattern of sunshine and suicide risk in a time frame of up to nine days and investigate possible lag and duration parameters of sunshine in the triggering of suicide, Greek daily suicide and solar radiance data were analyzed for a 10-year period using logistic regression models.

RESULTS

The solar radiance during the day before the suicide event was significantly associated with an increased suicide risk (OR=1.020 per MW/m2). The average solar radiance during the four previous days was also significantly associated with an increased suicide risk (OR=1.031 per MW/m2). Differences among genders include the longer sunshine exposure needed in males to trigger suicide, compared to females and a lag period of three to four days that was found to lapse in females till the suicide. The increase in suicide risk in June compared to December, attributable to the daily sunshine effect, varies from 52% to 88%, thus explaining the already known suicide monthly seasonality.

LIMITATIONS

No individual data on solar radiance exposure, mental disorders, alcohol consumption or suicide method were available.

CONCLUSION

The effect of sunshine in the triggering of suicide may be mediated through a mechanism with a specific lag and duration effect, during the nine days preceding suicide. We hypothesize that sunshine acts as a natural antidepressant which first improves motivation, then only later improves mood, thereby creating a potential short-term increased risk of suicide initially upon its application.

Biometeorological effects on worker absenteeism

The effects of six biometeorological variables (temperature, precipitation, air pressure, humidity, wind speed, and snow) on plant-wide worker absenteeism rates were investigated using 4 years of daily absence data (n=889). After holding constant temporal variables (years, season, and day of week), and then other biometeorological variables, all but one of the variables under consideration were uniquely and significantly related to absenteeism: temperature (r(partial)=-0.17***), precipitation (r(partial)=0.12***), air pressure (r(partial)=-0.09**), wind speed (r(partial)=0.11*), and snow (r(partial)=0.30***). Humidity (r(partial)=-00, ns) was not uniquely correlated. The adjusted R(2) of .29 (full R=0.55) for the entire model was also significant, illustrating the importance of these exogenous, meteorological variables in developing a prediction model of plant-wide absenteeism.

Geographic variation in suicide rates: relationships to social factors, migration, and ethnic history

Geographic variation in suicide rates is thought to be the result of interactions between two major components: the social organization combined with cultural tradition and biological or genetic factors. The present study examined regional patterns of suicide rates in European Russia. Our study looked at ethnic and national formations with respect to suicide patterns. The results indicated that the suicide rates vary greatly among the regions of the Russian Federation, with suicides more common in the northern regions of European Russia than in the south of the country. The south and north gradient of suicide distributions in Russia resemble that of other European countries. Throughout the Middle ages the north and northwest territory of present-day Russia has been an area of intensive interethnic contacts between the Old Slavs, which have colonized this territory, and native people of Finno-Ugrian and Baltic origin. The results indicated that the historical prevalence of the Finno-Ugrian component in the north of the country has possibly led to its higher suicide rate.

Association of meteorological factors with suicide

OBJECTIVE

To identify weather factors associated with an increased risk of suicide. In a number of prior studies an influence of meteorological conditions on the incidence of suicide or attempted suicide has been suggested.

METHOD

Official data on the suicide cases of the state of Tyrol, Austria, assessed over a period of 6 years (n = 702) were correlated with a number of meteorological factors assessed at eight weather stations.

RESULTS

The risk of committing suicide was significantly higher on days with high temperatures, low relative humidity or a thunderstorm and on days following a thunderstorm. The multiple logistic regression analysis left "temperature" and "thunderstorm on the preceding day" as significant factors, even after adjustment for sociodemographic and geographical variables.

CONCLUSION

Within the interaction of psychological and environmental influences in the development of suicidal ideation and behaviour, specific meteorological conditions may additionally contribute to the risk of suicide in predisposed individuals.

Weather and suicide: the present state of knowledge on the association of meteorological factors with suicidal behaviour

OBJECTIVE

To review the available literature on the association between daily and longer-term weather data and the incidence of attempted and completed suicide.

METHOD

A computerized search supplemented by a cross-check of the references sections of the thereby identified papers was performed.

RESULTS

A total of 27 studies looking for a relationship between attempted or completed suicide and weather or climate data were found. Most of the papers reported a statistical association of suicidal acts with at least one weather factor. However, the results are not conclusive and in part contradictory.

CONCLUSION

Possibly due to the high variance in methodological approaches of the studies it is not possible to identify a specific weather condition associated with a generally higher risk for suicide. Weather and seasonal effects may interact with each other. Environmental effects on brain function and weather-related interactions of people may be involved in the occurrence of suicidal behaviour.

Distribution of deaths by unintentional illicit drug overdose in Italy based on periodicity over time, 1984-2000

AIM

To assess whether substance-abusing people have a higher risk of dying from unintentional acute intoxication in specific periods of the year.

METHODS

A total of 15,792 deaths (males=14,259; females=1533) were ascertained to be due to unintentional acute intoxication by illicit drugs in Italy in the study period (1984-2000). Distribution of deaths by month was studied with circular statistics techniques, based on the maximization of mean vector length (MMVL) method. The Rayleigh test was used to verify the hypothesis of uniform distribution of the events across some relevant periods. Density estimates for significant periodicities were derived with the kernel method for circular variables.

RESULTS

Over the study period there was a steady increase in the number of deaths by overdose in Italy, affecting both genders, but more evident among males. The monthly distribution of deaths over the study period followed an uneven trend, with a slightly higher risk in the period between December and January, and in August, in both genders. The monthly distribution of deaths due to unintentional acute intoxication by illicit drugs appears influenced by non-casual oscillations following a thrice-yearly cycle, interlaced with a significantly more evident 6-monthly recurrence.

CONCLUSIONS

There does seem to be a higher risk of dying from unintentional overdose in specific periods of the year. Better knowledge of the factors affecting the risk of mortality among substance-abusing people--due to changes in environmental or biological rhythms--could allow prediction of negative events, hence their prevention.

Is the time of suicide a random choice? A new statistical perspective

The problem of the time distribution of suicide has aroused the interest of many authors, but their findings often appear uncertain and contradictory. These inconsistencies can be partially explained by both the choice of the sample and the statistical method used for the analysis. In this study, in order to reveal expected and unexpected periodicities in the time distribution of suicides, we analyzed a small but complete and very homogeneous sample of suicides which occurred in the Mountain District of the Metauro River Valley in Italy in the period 1960-1994. A recent circular statistics technique, the "maximization of mean vector length" was used. We found no significant weekly and lunar patterns, but significant seasonal and intraseasonal cycles, with peaks in March and at the beginning of each season. The superposition of these two significant cyclic trends was also studied.