Li Karen, Henderson Sarah B, Coker Eric S, McLean Kathleen E, Lee Michael Joseph
Environmental Health Services, British Columbia Centre for Disease Control, 655 W 12th Ave, Vancouver, BC, Canada.
School of Population & Public Health, University of British Columbia, Vancouver, Canada.
Environ Health. 2025 Apr 29;24(1):25. doi: 10.1186/s12940-025-01176-5.
Hot weather can negatively impact mental health and increase the risk of suicide. The relationship between heat and risk of suicide is not fully understood, and varies geographically across regions with differing climates, cultures, and socio-economic factors. The objective of this study was to investigate the relationship between hot summer days and suicides in British Columbia, Canada (BC).
A time-stratified case-crossover design was used to estimate the relationship between hot days (exposure) and suicide (outcome), considering same-day and two-day mean temperature. Conditional logistic regression was used to estimate the odds ratio (OR) for the association between hot days and suicides for three outcomes including: (1) suicide attempts by self-poisoning extracted from BC Drug and Poison Information Centre (DPIC) database (2012-2023); (2) completed suicides by self-poisoning extracted from BC vital statistics (2004-2023); and (3) completed suicides by violent methods extracted from BC vital statistics (2004-2023). Analyses were stratified by sex, age, ecological region, substance types used in self-poisonings, and by methods of violent suicide.
There were 9,599 suicide attempts via self-poisoning and 2,571 suicide deaths included in this study. Overall, hot days were associated with increased odds of self-poisoning suicide attempts and deaths, but not with suicide deaths via violent methods. The odds ratio [95% confidence interval] for suicide attempts via self-poisoning on hot days was 1.19 [1.11, 1.29], and 1.48 [1.12, 1.95] for suicide deaths. There was no effect of hot days on suicide deaths by violent methods. The associations varied by day of exposure, sex, age groups, and geography. The effect of hot days was greatest for suicide attempts and deaths involving opioids and elevated for suicide attempts involving opioid and analgesia combinations, analgesics alone, and alcohol.
The risk of suicide via self-poisoning was increased on hot summer days in BC, Canada. However, the relationship was influenced by other factors that vary among individuals and geographies. Policy decisions and future research for suicide-prevention during hot weather should consider sub-population susceptibility.
炎热天气会对心理健康产生负面影响，并增加自杀风险。高温与自杀风险之间的关系尚未完全明了，且因不同气候、文化和社会经济因素的地区而异。本研究的目的是调查加拿大不列颠哥伦比亚省（BC）炎热夏日与自杀之间的关系。
采用时间分层病例交叉设计来估计炎热天气（暴露因素）与自杀（结果）之间的关系，考虑当日和两日平均气温。使用条件逻辑回归来估计炎热天气与自杀之间关联的比值比（OR），涉及以下三个结果：（1）从BC药物与毒物信息中心（DPIC）数据库（2012 - 2023年）提取的自我中毒自杀未遂；（2）从BC生命统计数据（2004 - 2023年）提取的自我中毒自杀死亡；以及（3）从BC生命统计数据（2004 - 2023年）提取的暴力方式自杀死亡。分析按性别、年龄、生态区域、自我中毒使用的物质类型以及暴力自杀方式进行分层。
本研究纳入了9599例自我中毒自杀未遂和2571例自杀死亡案例。总体而言，炎热天气与自我中毒自杀未遂及死亡几率增加相关，但与暴力方式自杀死亡无关。炎热天气下自我中毒自杀未遂的比值比[95%置信区间]为1.19[1.11, 1.29]，自杀死亡的比值比为1.48[1.12, 1.95]。炎热天气对暴力方式自杀死亡无影响。这种关联因暴露日、性别、年龄组和地理位置而异。炎热天气对涉及阿片类药物的自杀未遂和死亡影响最大，对涉及阿片类药物与镇痛药组合、单独使用镇痛药以及酒精的自杀未遂影响也有所升高。
在加拿大不列颠哥伦比亚省，炎热夏日通过自我中毒的自杀风险增加。然而，这种关系受个体和地区间其他不同因素影响。炎热天气期间预防自杀的政策决策和未来研究应考虑亚人群易感性。
