Department of Primary Care and Public Health, Brighton and Sussex Medical School, UK.
Department of Biostatistics and Health Informatics, Institute of Psychiatry, Psychology and Neuroscience, King's College London, UK.
Br J Psychiatry. 2020 Dec;217(6):667-678. doi: 10.1192/bjp.2020.128.
The prevalence of mental health conditions and national suicide rates are increasing in many countries. Lithium is widely and effectively used in pharmacological doses for the treatment and prevention of manic/depressive episodes, stabilising mood and reducing the risk of suicide. Since the 1990s, several ecological studies have tested the hypothesis that trace doses of naturally occurring lithium in drinking water may have a protective effect against suicide in the general population.
To synthesise the global evidence on the association between lithium levels in drinking water and suicide mortality rates.
The MEDLINE, Embase, Web of Science and PsycINFO databases were searched to identify eligible ecological studies published between 1 January 1946 and 10 September 2018. Standardised regression coefficients for total (i.e. both genders combined), male and female suicide mortality rates were extracted and pooled using random-effects meta-analysis. The study was registered with PROSPERO (CRD42016041375).
The literature search identified 415 articles; of these, 15 ecological studies were included in the synthesis. The random-effects meta-analysis showed a consistent protective (or inverse) association between lithium levels/concentration in publicly available drinking water and total (pooled β = -0.27, 95% CI -0.47 to -0.08; P = 0.006, I2 = 83.3%), male (pooled β = -0.26, 95% CI -0.56 to 0.03; P = 0.08, I2 = 91.9%) and female (pooled β = -0.13, 95% CI -0.24 to -0.02; P = 0.03, I2 = 28.5%) suicide mortality rates. A similar protective association was observed in the six studies included in the narrative synthesis, and subgroup meta-analyses based on the higher/lower suicide mortality rates and lithium levels/concentration.
This synthesis of ecological studies, which are subject to the ecological fallacy/bias, supports the hypothesis that there is a protective (or inverse) association between lithium intakes from public drinking water and suicide mortality at the population level. Naturally occurring lithium in drinking water may have the potential to reduce the risk of suicide and may possibly help in mood stabilisation, particularly in populations with relatively high suicide rates and geographical areas with a greater range of lithium concentration in the drinking water. All the available evidence suggests that randomised community trials of lithium supplementation of the water supply might be a means of testing the hypothesis, particularly in communities (or settings) with demonstrated high prevalence of mental health conditions, violent criminal behaviour, chronic substance misuse and risk of suicide.
许多国家的心理健康状况和全国自杀率都在上升。锂在药理学剂量下被广泛有效地用于治疗和预防躁狂/抑郁发作，稳定情绪并降低自杀风险。自 20 世纪 90 年代以来，几项生态学研究检验了这样一个假设，即饮用水中天然存在的痕量锂可能对一般人群的自杀具有保护作用。
综合全球关于饮用水中锂水平与自杀死亡率之间关联的证据。
检索了 MEDLINE、Embase、Web of Science 和 PsycINFO 数据库，以确定 1946 年 1 月 1 日至 2018 年 9 月 10 日期间发表的合格的生态学研究。使用随机效应荟萃分析提取并汇总了总（即男女混合）、男性和女性自杀死亡率的标准化回归系数。该研究已在 PROSPERO（CRD42016041375）中注册。
文献检索共识别出 415 篇文章；其中，有 15 项生态学研究被纳入综合分析。随机效应荟萃分析显示，公开饮用水中锂的水平/浓度与总自杀率（汇总β=-0.27，95%CI-0.47 至-0.08；P=0.006，I2=83.3%）、男性（汇总β=-0.26，95%CI-0.56 至 0.03；P=0.08，I2=91.9%）和女性（汇总β=-0.13，95%CI-0.24 至-0.02；P=0.03，I2=28.5%）之间存在一致的保护（或相反）关联。在包括的叙述性综合研究中也观察到了类似的保护关联，并且基于较高/较低自杀死亡率和锂水平/浓度的亚组荟萃分析也是如此。
这项生态学研究的综合分析，尽管存在生态学谬误/偏差，但支持这样一个假设，即从公共饮用水中摄取锂与人群水平的自杀死亡率之间存在保护（或相反）关联。饮用水中的天然锂可能具有降低自杀风险的潜力，并且可能有助于稳定情绪，特别是在自杀率相对较高且饮用水中锂浓度范围较大的人群中。所有现有证据表明，对饮用水进行锂补充的随机社区试验可能是检验这一假设的一种手段，特别是在已经证明心理健康状况、暴力犯罪行为、慢性物质滥用和自杀风险普遍较高的社区（或环境）中。
