Negev Environmental Health Research Institute, Soroka University Medical Center, Beer-Sheva, Israel.
Department of Environmental Health, Harvard T.H. Chan School of Public Heath, Boston, MA, 02115, USA.
Environ Res. 2020 May;184:109314. doi: 10.1016/j.envres.2020.109314. Epub 2020 Feb 27.
Suicidal behavior is determined by the consequence of an interaction between biological, psychological and sociological factors, as well as between individual and environmental effects. Fluctuations in meteorological factors can modify human behavior and affect suicidal rates. We hypothesize that high temperatures can be associated with an increase rate of suicidal attempts.
We included all the patients admitted to Soroka University Medical Center (SUMC) due to suicide attempts between the years 2002-2017 and were residents of Southern Israel. We computed two sets of regression models: first, a time stratified case-crossover design to control for seasonality and individual differences. Results are presented as odds ratio (OR) with confidence interval (CI); and then, time-series analyses to calculate the incidence rate ratio (IRR) and the cumulative effect of temperature on the daily incidences of emergency department (ED) admissions after suicide attempts. We stratified the analyses by demographic variables to identify significant individual differences.
We identified 3100 attempts, by 2338 patients who lived in Be'er Sheva between 16 and 90 years of age; 421 patients made 2+ attempts. Suicide attempts were associated with a 5 °C increase during the summer season (OR 1.59, 95% CI 1.22-2.08) and a 5 °C increase in all seasons was associated with those who have made multiple attempts (OR 1.18, 95% CI 1.0005-1.38). The cumulative effect of 5 °C increment is associated with more suicide attempts over 2 days (IRR 1.10, 95% CI 0.98; 1.24) and 5 days (IRR 1.04, 95% CI 1.00; 1.08). The associations were greater for patients with psychiatric diagnosis and patients with multiple attempts. In a stratified analysis by individual characteristics we didn't find significant association.
High temperatures and low amount of precipitations are evidently of great impact on people's susceptibility to suicidal behavior, especially for individuals who have had a prior suicide attempt. Our findings indicate the need for public health attention in the summer when temperature increases precipitously over days, especially for those who have made a prior suicide attempt.
自杀行为是由生物、心理和社会学因素以及个体与环境影响相互作用的结果所决定的。气象因素的波动会改变人类的行为并影响自杀率。我们假设高温可能与自杀企图发生率的增加有关。
我们纳入了 2002 年至 2017 年间因自杀企图而入住索罗卡大学医学中心（SUMC）且居住在以色列南部的所有患者。我们计算了两组回归模型：首先，采用时间分层病例交叉设计来控制季节性和个体差异。结果表示为比值比（OR）和置信区间（CI）；然后，进行时间序列分析以计算自杀企图后急诊科（ED）每日入院率的温度累积效应和发病率比（IRR）。我们按人口统计学变量对分析进行分层，以确定显著的个体差异。
我们确定了 3100 次企图，涉及 2338 名年龄在 16 至 90 岁之间居住在贝尔谢巴的患者；421 名患者有 2 次以上的企图。自杀企图与夏季气温升高 5°C（OR 1.59，95%CI 1.22-2.08）有关，所有季节气温升高 5°C 与多次企图有关（OR 1.18，95%CI 1.0005-1.38）。5°C 增量的累积效应与 2 天（IRR 1.10，95%CI 0.98；1.24）和 5 天（IRR 1.04，95%CI 1.00；1.08）内自杀企图次数增加有关。对于有精神科诊断和多次企图的患者，相关性更大。按个体特征进行分层分析时，我们没有发现显著的相关性。
高温和低降水量显然对人们的自杀行为易感性有很大影响，特别是对那些有过自杀企图的人。我们的研究结果表明，在夏季气温急剧升高的几天内，需要特别关注公共卫生，特别是那些有过自杀企图的人。
