Dalla Lana School of Public Health, University of Toronto, 155 College St, Toronto, Ontario, M5T 3M7, Canada.
BMC Public Health. 2021 May 25;21(1):974. doi: 10.1186/s12889-021-11001-6.
Suicide is among the top 10 leading causes of premature morality in the United States and its rates continue to increase. Thus, its prevention has become a salient public health responsibility. Risk factors of suicide transcend the individual and societal level as risk can increase based on climatic variables. The purpose of the present study is to evaluate the association between average temperature and suicide rates in the five most populous counties in California using mortality data from 1999 to 2019.
Monthly counts of death by suicide for the five counties of interest were obtained from CDC WONDER. Monthly average, maximum, and minimum temperature were obtained from nCLIMDIV for the same time period. We modelled the association of each temperature variable with suicide rate using negative binomial generalized additive models accounting for the county-specific annual trend and monthly seasonality.
There were over 38,000 deaths by suicide in California's five most populous counties between 1999 and 2019. An increase in average temperature of 1 °C corresponded to a 0.82% increase in suicide rate (IRR = 1.0082 per °C; 95% CI = 1.0025-1.0140). Estimated coefficients for maximum temperature (IRR = 1.0069 per °C; 95% CI = 1.0021-1.0117) and minimum temperature (IRR = 1.0088 per °C; 95% CI = 1.0023-1.0153) were similar.
This study adds to a growing body of evidence supporting a causal effect of elevated temperature on suicide. Further investigation into environmental causes of suicide, as well as the biological and societal contexts mediating these relationships, is critical for the development and implementation of new public health interventions to reduce the incidence of suicide, particularly in the face increasing temperatures due to climate change.
自杀是导致美国过早死亡的 10 大主要原因之一，其死亡率持续上升。因此，预防自杀已成为一项突出的公共卫生责任。自杀的风险因素超越了个人和社会层面，因为风险可以根据气候变量而增加。本研究的目的是使用 1999 年至 2019 年的死亡率数据，评估加利福尼亚州五个人口最多的县的平均温度与自杀率之间的关系。
从 CDC WONDER 获取五个感兴趣的县的自杀死亡逐月计数。在同一时期，从 nCLIMDIV 获取每月平均、最高和最低温度。我们使用负二项广义加性模型对每种温度变量与自杀率的关系进行建模，该模型考虑了县特定的年度趋势和每月季节性。
在 1999 年至 2019 年期间，加利福尼亚州五个人口最多的县有超过 38000 人死于自杀。平均温度升高 1°C 对应于自杀率增加 0.82%（IRR=1.0082/°C；95%CI=1.0025-1.0140）。最高温度（IRR=1.0069/°C；95%CI=1.0021-1.0117）和最低温度（IRR=1.0088/°C；95%CI=1.0023-1.0153）的估计系数相似。
本研究为越来越多的证据支持高温对自杀的因果影响提供了补充。进一步调查环境对自杀的影响，以及在这些关系中起中介作用的生物和社会背景，对于开发和实施新的公共卫生干预措施以减少自杀发生率至关重要，特别是在面对气候变化导致的气温升高时。
