Department of Epidemiology and Health Statistics, School of Public Health, Anhui Medical University, Hefei, Anhui 230032, China; Anhui Province Key Laboratory of Major Autoimmune Disease, China.
Department of Epidemiology and Health Statistics, School of Public Health, Anhui Medical University, Hefei, Anhui 230032, China; Anhui Province Key Laboratory of Major Autoimmune Disease, China.
Sci Total Environ. 2019 Jan 1;646:1021-1029. doi: 10.1016/j.scitotenv.2018.07.098. Epub 2018 Jul 30.
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.
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).
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.
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.
许多先前的研究已经调查了阳光时间、温度和自杀之间的关系，但研究结果不一致。我们进行了这项荟萃分析，旨在提供关于阳光时间和温度是否会影响自杀风险的明确证据。
在 2018 年 7 月 7 日之前，我们在三个电子数据库 PubMed、Web of Science 和 Cochrane 中搜索了相关文献。通过研究设计（即暴露时间分辨率、温度测量和自杀分类）和人群脆弱性（即性别、国民收入水平、气候带和研究地点）来检查效应估计值的研究间异质性。
关于温度与自杀的关联，我们确定了 14 项研究，为荟萃分析提供了 23 项效应估计值。我们的随机效应模型表明，温度每升高 1°C，自杀的发生率就会显著增加 1%（发病率比 (IRR) = 1.01；95%CI = 1.00-1.02；p < 0.05）。至于阳光持续时间与自杀的关系，我们使用固定效应模型汇总了来自 4 项研究的 11 项效应估计值。阳光持续时间（每增加 1 小时）与自杀风险之间没有显著关联，合并的 IRR 为 1.00（95%CI = 0.99-1.01；p > 0.05）。先前研究的效应估计值之间存在显著的异质性，女性组、每天进行分析的研究以及使用平均温度作为暴露指标的研究的异质性显著降低。
我们的研究结果表明，温度升高与自杀发生率之间存在显著的正相关，而阳光持续时间与自杀发生率之间没有显著的关联。生活在热带和温带地区或中等收入水平的人群可能特别容易受到温度升高的影响。
