Association between lithium in tap water and suicide mortality rates in Miyazaki Prefecture

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.

In vitro gastrointestinal digestion and bioavailability of lithium from processed lithiated and nonlithiated white Agaricus bisporus mushrooms

AIM

In order to avoid side effects of lithium doses in some patients, some commonly cultivated mushroom species including A. bisporus have been successfully lithiated, with the potential to provide more acceptable sources of Li. This study assessed the in vitro release (potential bioaccessibility) and possible intake of Li using the action of artificial gastrointestinal juices on lithiated and nonlithiated (control) button mushrooms (Agaricus bisporus) that were subjected to certain modes of culinary processing.

METHODS

In the in vitro release study, mushrooms were processed using a number of routinely used domestic treatments including rehydrating dried mushrooms, blanching and blanching followed by pickling of fresh or frozen mushrooms. The in vitro digestion procedure used artificial gastrointestinal juices in a two-stage methodology that was adapted from 'The Bioaccessibility Research Group of Europe' method. The Li concentrations were determined using an inductively coupled argon plasma-dynamic reactive cell-mass spectrometer.

RESULTS

Lithium was found to be more bioaccessible from caps of lithiated mushrooms compared with nonlithiated. Releases from the caps and stipes of blanched or blanched and then pickled mushrooms through gastric digestion ranged from 32 ± 2 to 50 ± 1% relative to the dried product and was lower for gastrointestinal digestion, which ranged from 16 ± 1 to 20 ± 1%.

CONCLUSION

Losses of Li sustained through blanching or blanching followed by pickling of fresh mushrooms (41-87% wet weight) combined with limited accessibility during gastrointestinal release (16-55%) result in much lower bioavailability of the dose from lithiated products. A 300-g meal would provide <5% of the Li (6 mg) required for potential preventative treatments, such as reducing suicide rates and lowering dementia risk.

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.

Association between lithium levels in drinking water and suicide rates: Role of affective disorders

OBJECTIVE

The study aimed to assess the association between lithium levels in drinking water from public supplies and suicide rates in different municipalities of Lithuania in relation with incidence of affective disorders.

METHODS

53 drinking water samples were analysed from the main public drinking water systems of the country's municipalities. Lithium levels were determined using the ion chromatography method. Information on all registered affective disorders across all age groups and gender within the 5-year period was obtained from the Department of Statistics, and was averaged across the investigation time period. For the statistical analysis, lithium levels were averaged per municipality and plotted against suicide standardized mortality rates per 100,000 populations, within the 5-year period.

RESULTS

We found that lithium levels in drinking water are positively associated with the incidence of affective disorders. Our findings suggest higher incidence rates of affective disorders in the municipalities with a lithium level in drinking water above median compared to those in the municipalities with a lithium level below median and with the same socio-demographic and psychiatric characteristics. Suicide mortality rates are inversely associated with lithium levels in drinking water only in municipalities with higher lithium levels (above median) and with a high rate of affective disorders.

CONCLUSION

Based on our study results and insights we generate the following hypothesis for the further research, that lithium level in drinking water might have an important protective effect against suicide rates in the population with affective disorders.

Position sensitive measurement of trace lithium in the brain with NIK (neutron-induced coincidence method) in suicide

Mood disorder is the leading intrinsic risk factor for suicidal ideation. Questioning any potency of mood-stabilizers, the monovalent cation lithium still holds the throne in medical psychiatric treatment. Furthermore, lithium`s anti-aggressive and suicide-preventive capacity in clinical practice is well established. But little is still known about trace lithium distribution and any associated metabolic effects in the human body. We applied a new technique (neutron-induced coincidence method “NIK”) utilizing the ⁶Li(n,α)³H reaction for the position sensitive, 3D spatially resolved detection of lithium traces in post-mortem human brain tissue in suicide versus control. NIK allowed, for the first time in lithium research, to collect a three dimensional high resolution map of the regional trace lithium content in the non lithium-medicated human brain. The results show an anisotropic distribution of lithium, thus indicating a homeostatic regulation under physiological conditions as a remarkable link to essentiality. In contrast to suicide we could empirically prove significantly higher endogenous lithium concentrations in white compared to gray matter as a general trend in non-suicidal individuals and lower lithium concentrations in emotion-modulating regions in suicide.