Association between naturally occurring lithium in drinking water and suicide rates: systematic review and meta-analysis of ecological studies

Title	Association between naturally occurring lithium in drinking water and suicide rates: systematic review and meta-analysis of ecological studies
Authors	Anjum Memon, Imogen Rogers, Sophie M. D. D. Fitzsimmons, Ben Carter, Rebecca Strawbridge, Diego Hidalgo-Mazzei, Allan H. Young
Magazine	The British Journal of Psychiatry
Date	07/27/2020
DOI	10.1192/bjp.2020.128
Introduction	Globally, the prevalence of mental health conditions and national suicide rates are showing an upward trend. Lithium is a well-established and effective treatment, in pharmacological doses, for managing and preventing manic/depressive episodes, thereby stabilising mood and lowering suicide risk. Since the 1990s, numerous ecological studies have put forth the proposition that trace amounts of naturally occurring lithium in drinking water might offer a protective influence against suicide within the general population. This study aimed to compile the worldwide evidence regarding the correlation between lithium concentrations in drinking water and suicide mortality rates. A systematic search was conducted across MEDLINE, Embase, Web of Science, and PsycINFO databases for relevant ecological studies published between 01/01/1946 and 10/09/2018. Standardised regression coefficients for total, male, and female suicide mortality rates were extracted and combined using random-effects meta-analysis. The search yielded 415 articles, from which 15 ecological studies were selected for synthesis. The meta-analysis consistently indicated a protective, or inverse, relationship between lithium levels in publicly available drinking water and total (pooled β = −0.27, 95% CI −0.47 to −0.08), male (pooled β = −0.26, 95% CI −0.56 to 0.03), and female (pooled β = −0.13, 95% CI −0.24 to −0.02) suicide mortality rates. Comparable protective associations were observed in a narrative synthesis of six studies and in subgroup meta-analyses based on varying suicide mortality and lithium concentration levels. While acknowledging the potential for ecological fallacy/bias inherent in ecological studies, this synthesis supports the hypothesis of a protective association between lithium intake from public drinking water and population-level suicide mortality. Naturally occurring lithium in drinking water holds potential for reducing suicide risk and assisting in mood stabilisation, particularly in populations with elevated suicide rates and regions exhibiting a wider range of lithium concentrations in their water supply. The existing evidence suggests that randomised community trials involving lithium supplementation of water supplies could serve as a valuable approach to validate this hypothesis, especially in communities facing high prevalence of mental health conditions, violent criminal behaviour, chronic substance misuse, and suicide risk.
Quote	Anjum Memon, Imogen Rogers and Sophie M. D. D. Fitzsimmons et al. Association between naturally occurring lithium in drinking water and suicide rates: systematic review and meta-analysis of ecological studies. The British Journal of Psychiatry. 2020. DOI: 10.1192/bjp.2020.128
Element	Lithium (Li)
Industry	Pharmaceutical Industry , Research & Laboratory