Investigation of the association between lithium levels in drinking water and suicide mortality in Hungary

History of Suicide Prevention with Lithium Treatment

Suicidal behavior is prevalent among individuals with psychiatric illnesses, especially mood, substance abuse, and psychotic disorders. Over the past several decades, lithium treatment in patients with mood disorders has been increasingly used to lower the risk of suicidal behavior. This overview considers that lithium treatment has the most abundant evidence of reducing suicidal behavior. It also examines the hypothesis that higher natural lithium levels in drinking water correlate with reduced suicide rates. We report findings from trials comparing lithium treatment with its absence, placebos, or alternative treatments for suicide prevention and address substantial challenges in such studies. The mechanisms behind lithium's potentially protective effects against suicidal behavior remain uncertain. However, it is believed that lithium may produce anti-aggressive/anti-impulsive effects that directly contribute to anti-suicidal outcomes and mood-stabilizing effects that indirectly lead to the same results. Anti-aggressive/anti-impulsive effects may be obtained at the very low levels of lithium present in drinking water, whereas recurrence prevention may be attained at therapeutic levels.

Cancer Risk and Estimated Lithium Exposure in Drinking Groundwater in the US

Importance

Lithium is a naturally occurring element in drinking water and is commonly used as a mood-stabilizing medication. Although clinical studies have reported associations between receiving lithium treatment and reduced cancer risk among patients with bipolar disorder, to our knowledge, the association between environmental lithium exposure and cancer risk has never been studied in the general population.

Objectives

To evaluate the association between exposure to lithium in drinking groundwater and cancer risk in the general population.

Design, Setting, and Participants

This cohort study included participants with electronic health record and residential address information but without cancer history at baseline from the All of Us Research Program between May 31, 2017, and June 30, 2022. Participants were followed up until February 15, 2023. Statistical analysis was performed from September 2023 through October 2024.

Exposure

Lithium concentration in groundwater, based on kriging interpolation of publicly available US Geological Survey data on lithium concentration for 4700 wells across the contiguous US between May 12, 1999, and November 6, 2018.

Main Outcome and Measures

The main outcome was cancer diagnosis or condition, obtained from electronic health records. Stratified Cox proportional hazards regression models were used to estimate the hazard ratios (HRs) and 95% CIs for risk of cancer overall and individual cancer types for increasing quintiles of the estimated lithium exposure in drinking groundwater, adjusting for socioeconomic, behavioral, and neighborhood-level variables. The analysis was further conducted in the western and eastern halves of the US and restricted to long-term residents living at their current address for at least 3 years.

Results

A total of 252 178 participants were included (median age, 52 years [IQR, 36-64 years]; 60.1% female). The median follow-up time was 3.6 years (IQR, 3.0-4.3 years), and 7573 incident cancer cases were identified. Higher estimated lithium exposure was consistently associated with reduced cancer risk. Compared with the first (lowest) quintile of lithium exposure, the HR for all cancers was 0.49 (95% CI, 0.31-0.78) for the fourth quintile and 0.29 (95% CI, 0.15-0.55) for the fifth quintile. These associations were found for all cancer types investigated in both females and males, among long-term residents, and in both western and eastern states. For example, for the fifth vs first quintile of lithium exposure for all cancers, the HR was 0.17 (95% CI, 0.07-0.42) in females and 0.13 (95% CI, 0.04-0.38) in males; for long-term residents, the HR was 0.32 (95% CI, 0.15-0.66) in females and 0.24 (95% CI, 0.11-0.52) in males; and the HR was 0.01 (95% CI, 0.00-0.09) in western states and 0.34 (95% CI, 0.21-0.57) in eastern states.

Conclusions and Relevance

In this cohort study of 252 178 participants, estimated lithium exposure in drinking groundwater was associated with reduced cancer risk. Given the sparse evidence and unknown mechanisms of this association, follow-up investigation is warranted.

Too early to add lithium to drinking water? No association between lithium and suicides in a pre-registered Swiss study

BACKGROUND

Suicide remains a significant public health concern worldwide. Ecological studies reported decreased suicide rates with higher levels of trace lithium levels in drinking water, leading to suggestions of adding lithium to drinking water as a preventative anti-suicide strategy. However, the evidence remains inconclusive, and thus more data are needed.

METHODS

This pre-registered study analyzed the association between lithium concentrations in drinking water and suicide rates across 1043 municipalities in Switzerland between 1981 and 2021. We used bivariate correlation analysis, ordinary regression models, and spatial regression models, while accounting for potential confounding variables.

RESULTS

There were no significant associations between lithium levels in drinking water and suicide rates, as determined by correlation analysis (r = -0.03, 95 % CI -0.09-0.03, p = 0.33), and by multivariable ordinary and spatial regression models.

LIMITATIONS

The correlation between levels of lithium in tap water and the serum of individuals is unknown and ecological studies are inherently limited to establish a causal association.

CONCLUSIONS

The null finding in our study adds to the ongoing debate on the effectiveness of trace lithium in drinking water as a public health intervention for suicide prevention, indicating that calls for lithium supplementation are still premature. These findings highlight the need for further research with transparent and replicable methodologies to clarify the potential role of lithium in suicide prevention.

Lithium: Fifteen Years Later

BACKGROUND

The 75th anniversary of introducing lithium into modern psychiatry is recognized, attested by the 1949 paper of John Cade. About this event, my editorial in the special 2010 issue of Neuropsychobiology was titled "Lithium: Sixty Years Thereafter." Since then, fifteen more years have brought further information about lithium. This paper makes a narrative review of the most important articles published in this period.

SUMMARY

The selected key literature of 2010-2024 addressed lithium prophylactic efficacy in bipolar disorder (BD), including pediatric, recurrent depression, and lithium augmentation of antidepressants in treatment-resistant depression (TRD). Novel data have been obtained for lithium adverse effects (kidney, thyroid) and beneficial outcomes of long-term lithium administration (anti-suicidal, neuroprotective, antiviral, and others). The results on the mechanisms of lithium action covered genetic investigations of the Consortium of Lithium Genetics (ConLiGen) and in vitro studies with induced pluripotent stem cells and lymphoblastoid cell lines. The underutilization of lithium nowadays was emphasized, and the ways to overcome it were considered.

KEY MESSAGES

Lithium remains the choice drug for recurrence prevention in BD, also in adolescents, and a significant option for augmentation of antidepressants in TRD. The adverse side effects should be carefully followed and managed according to current guidelines. There are also beneficial lithium impacts, of which anti-suicidal and anti-dementia seem the most important. Most of the results of neurobiological studies on lithium mechanisms may be related to lithium response and some (e.g., immunomodulatory) to the pathogenesis of BD. Better education about lithium could make more patients the beneficiary of this drug.

Appraisal of contamination, hydrogeochemistry, and Monte Carlo simulation of health risks of groundwater in a lithium-rich ore area

This study incorporated hydrogeochemical facies, the entropy-weighted water quality index (EWQI), multivariate statistics, and probabilistic human exposure assessment to investigate hydrogeochemistry, analyze groundwater quality, and estimate potential risks to human health in a lithium-rich ore area (Jadar River basin, Serbia). The findings designated the Ca·Mg-HCO3 hydrogeochemical type as the predominant type of groundwater, in which rock weathering and evaporation control the major ion chemistry. Due to the weathering of a lithium-rich mineral (Jadarite), the lithium content in the groundwater was very high, up to 567 mg/L, with a median value of 4.3 mg/L. According to the calculated EWQI, 86.4% of the samples belong to poor and extremely poor quality water for drinking. Geospatial mapping of the studied area uncovered several hotspots of severely contaminated groundwater. The risk assessment results show that groundwater contaminants pose significant non-carcinogenic and carcinogenic human health risks to residents, with most samples exceeding the allowable limits for the hazard index (HI) and the incremental lifetime cancer risk (ILCR). The ingestion exposure pathway has been identified as a critical contaminant route. Monte Carlo risk simulation made apparent that the likelihood of developing cancerous diseases is very high for both age groups. Sensitivity analysis highlighted ingestion rate and human body weight as the two most influential exposure factors on the variability of health risk assessment outcomes.

Progress and trends of research on mineral elements for depression

Objective

To explore the research progress and trends on mineral elements and depression.

Methods

After querying the MeSH database and referring to the search rules, the search terms were selected and optimized to obtain the target literature collection. We analyzed the general characteristics of the literature, conducted network clustering and co-occurrence analysis, and carried out a narrative review of crucial literature.

Results

Bipolar disorder was a dominant topic in the retrieved literature, which saw a significant increase in 2010 and 2019-2020. Most studies focused on mineral elements, including lithium, calcium, magnesium, zinc, and copper. The majority of journals and disciplines were in the fields of psychiatry, neuropsychology, neuropharmacology, nutrition, medical informatics, chemistry, and public health. The United States had the highest proportion in terms of paper sources, most-cited articles, high-frequency citations, frontier citations, and high centrality citation. Regarding the influence of academic institutions, the top five were King's College London, the Chinese Academy of Sciences, University of Barcelona, INSERM, and Heidelberg University. Frontier keywords included bipolar disorder, drinking water, (neuro)inflammation, gut microbiota, and systematic analysis. Research on lithium response, magnesium supplementation, and treatment-resistant unipolar depression increased significantly after 2013.

Conclusion

Global adverse events may have indirectly driven the progress in related research. Although the literature from the United States represents an absolute majority, its influence on academic institutions is relatively weaker. Multiple pieces of evidence support the efficacy of lithium in treating bipolar disorder (BD). A series of key discoveries have led to a paradigm shift in research, leading to increasingly detailed studies on the role of magnesium, calcium, zinc, and copper in the treatment of depression. Most studies on mineral elements remain diverse and inconclusive. The potential toxicity and side effects of some elements warrant careful attention.

Study around the Barroso mine (Portugal): Baseline levels of lithium for assessing future exposure and risks from Li mining activity

The energetic green transition is increasing the demand for lithium (Li) exploitation. However, the Li supply faces challenges like limited reserves and environmental concerns. This pioneer study aims to characterize the Li concentrations in the region around the Barroso mine, in Portugal, by collecting and analyzing samples of cabbage, potato, drinking and irrigation water and soil from two nearby sites, and performing a preliminary exposure and risk assessment of local populations. Li levels ranged between 20 and 589 μg/kg in cabbages (n = 23), 2.3-21 μg/kg in potatoes (n = 21), 1.1-5.9 μg/L in drinking water (n = 10), 1.1-15 μg/L in irrigation water (n = 23) and 35-121 mg/kg in soils (n = 23). Significant differences in Li content between sampling sites were observed only for cabbage samples. The risk assessment revealed that none of the participants exceeded the provisional reference dose (p-RfD) (2 μg/kg bw/day), with a hazard quotient (HQ) < 1, suggesting no health concerns for the population. It is expected that the studied area will be affected by the future expansion of the mine concession, thus this pioneer study is crucial for future research as it establishes a initial database for evaluating the potential impact of mining activity on the environment and the population's exposure to Li.

Prevention of suicidal behavior with lithium treatment in patients with recurrent mood disorders

Suicidal behavior is more prevalent in bipolar disorders than in other psychiatric illnesses. In the last thirty years evidence has emerged to indicate that long-term treatment of bipolar disorder patients with lithium may reduce risk of suicide and attempts, with possibly similar benefits in recurrent major depressive disorder. We review and update selected research literature on effects of lithium treatment in reducing suicidal behavior and consider proposals that higher levels of lithium in drinking water may be associated with lower suicide rates. We summarize results of a growing number of randomized, controlled studies of lithium treatment for suicide prevention including comparisons with placebos or alternative treatments, and comment on the severe challenges of such trials. The basis of a proposed protective effect of lithium against suicidal behaviors remains uncertain but may include protective effects against recurrences of depressive phases of mood disorders, especially with mixed features or agitation, and possibly through beneficial effects on impulsivity, agitation and dysphoric mood.

Lithium concentration in tap water, bottled mineral water, and Danube River water in Hungary

Due to increased manufacture and recycling of lithium batteries across the world, we may anticipate a rise in lithium pollution in the aquatic environment and drinking water reservoirs. In order to investigate the current status regarding the lithium content in Hungarian tap waters, samples were collected from the public drinking water supply systems of 19 county seats in Hungary during seasonally selected times. Depending on the water sources, such as bank-filtrated river water, surface water from open reservoirs, and groundwater, the lithium concentrations varied between 0.90-4.23, 2.12-11.7 and 1.11-31.4 µg/L, respectively, while the median values were 3.52, 5.02 and 8.55 µg/L, respectively. The lithium concentration in the bottled Hungarian mineral waters was also determined since the daily intake of lithium can be influenced by the consumption of mineral waters. The concentrations ranged from 4.2 to 209 µg/L, while the median value was only 17.8 µg/L. Additionally, a correlation was only found between lithium and potassium concentrations. The lithium concentration was also assessed at ten sampling locations in the Hungarian segment of the Danube River since the Danube water is also a water source for additional drinking water utilities using bank filtration technology. The mean and median lithium concentrations were 2.78 and 2.64 µg/L, respectively.

An investigation into the association between suicide mortality rate and lithium levels in potable water: a review study

This study aimed to investigate the association between lithium levels in potable water and suicide mortality rates in the total inhabitants. We systematically searched Embase, PubMed/MEDLINE, Scopus, PubMed Central (PMC), Google Scholar databases, as well as medRxiv using the following keywords: drinking water, lithium, standardized mortality ratio (SMR), tap water, suicide, and ground water. Pearson regression analysis was used to test an association between variables with 95% confidence interval (CI). A value of P < 0.05 was considered significant. A total of 16 eligible articles were identified. Lithium concentrations in drinking water range from 0.4 to 32.9 μg/l. Average rates of suicide mortality (per 100 000 capita) range between 0.790 (±0.198) and 123 (±50). About 16 original studies confirmed the inverse relationship between lithium concentrations in potable water and suicide mortality rates (R = -0.576; R2 = 0.3323; 95% CI, -0.820 to -0.325; β = -0.3.2; P = 0.019). High lithium concentrations in potable water were associated with decreased suicide rates. We concluded that lithium concentration in potable water was inversely associated with suicide mortality rates among a total population. However, further research is required to clarify the relationship between lithium concentrations in drinking water and suicide rate.

Mini-review: Anomalous association between lithium data and lithium use

This mini-review aims to show a discrepancy between favorable data of lithium's therapeutic activity and the decreased use of the drug worldwide. The data point to lithium as the best mood stabilizer in the maintenance treatment of bipolar disorder for the prevention of manic and depressive recurrences. The second most encouraging psychiatric use of lithium is the augmentation of antidepressants in treatment-resistant depression. In addition to its mood-stabilizing properties, lithium is the most efficacious antisuicidal drug among all mood stabilizers. The drug also exerts antiviral, immunomodulatory, and neuroprotective effects which may be of major clinical value. On the other hand, the data of lithium use show that its therapeutic application in many countries has declined. A reason for this can be the introduction and heavy promotion of other mood-stabilizers, while lithium is an "orphan" drug with the minimal interest of any drug company. Probably, very important is also a perception of lithium as a "toxic drug", pointing to its side effects, mainly thyroid, renal and cognitive ones. In recent years, several proposals to turn back this anomalous association appeared, challenging a negative perception of lithium and optimizing its long-term administration. They show the data on lithium superiority over other mood stabilizers and point to the proper management of the lithium-induced side effects. This endeavor aims to allow a larger number of mood disorder patients to become beneficiaries of lithium use.