Loading...
3 results
Search Results
Now showing 1 - 3 of 3
- Association between natural exposure to lithium and suicide rate: an ecological and human biomonitoring study in northern PortugalPublication . Cainé, Laura; Santos, Agostinho; Almeida, Agostinho; Gonçalves, Carolina; Azevedo, Rui; Costa, Félix; Couto, Cristina; Duro, MarySeveral studies have found an inverse relationship between lithium levels in drinking water and the suicide rate in the general population [1,2]. However, this observation has failed in other studies [3], including in Portugal [4], and there seems to be a threshold concentration (30 μg/L) above which this “protective” effect of lithium becomes noticeable [3]. The main limitation of these “ecological” studies is that they assume a direct association between lithium concentration in drinking water and population lithium intake. However, other sources can significantly contribute to the total daily intake of lithium, namely various dietary sources. Determination of urinary lithium levels may be a better approach in the study of this issue (the possible association between natural lithium exposure and suicide rates), by allowing a more accurate assessment of actual lithium intake by the general population. In this context, we conducted a comparative study between two regions of northern Portugal with very different relative risk (RR) for suicide, according to a study by Loureiro et al. [5], roughly corresponding to the metropolitan area of Porto (“AMP”; west/coast, with the lowest RR nationally: 0.28) and the region of Trás-os-Montes (“TM”; northeast, with the third highest RR: 1.67). The study included both the determination of lithium concentration in water samples (from domestic public supply and other sources, including surface water) and in urine samples from individuals residing in the two regions. There was no clear inverse association between lithium levels and the RR of suicide. The median concentration in water was slightly higher in the region with the lowest RR (AMP) [3.4 μg/L (n=59) vs. 2.5 μg/L (n=72)], but the median concentration in urine was lower [22.6 μg/L (n=131) vs. 27.5 μg/L (n=51)]. However, in this region (AMP) a significantly higher percentage of individuals with high lithium urinary levels (> 80 μg/L) was found: 15% (20/131) vs. only 6% (3/51). The reasons for this large inter- individual variability in urinary lithium levels should be investigated.
- Lithium urinary levels and suicide mortality rate in PortugalPublication . Cainé, Laura; Gonçalves, Carolina; Santos, Agostinho; Almeida, AgostinhoIntroduction: Suicide is a major public health problem, estimated to be the cause of death of more than 700.000 people a year worldwide. Lithium is not considered an essential physiological element. However, a high dietary intake of lithium has been associated with beneficial effects, particular, a decrease in the suicide rate, possibly due to lithium having a known therapeutic role in bipolar disorder [1]. Objectives: To assess the existing scientific evidence on the relation between lithium levels in drinking water and the suicide rate in distinct world regions. Methods: An exhaustive literature search on the topic was carried out on PubMed, between January and February 2022. Results: In the majority of the published studies, the suicide mortality rate was shown to be inversely related to lithium levels in drinking water. However, this relation was not observed in some studies, including in Portugal. Additionally, it seems that a minimum concentration of 30 μg/L is the threshold from which such relation is observed [2,3,4,5]. Conclusions: An inverse relation has been demonstrated between the lithium concentration in drinking water and the suicide mortality rate. Portugal presented itself as one of the exceptions. The main limitation of these studies (ecological studies) is that they assume a correlation between the concentration of lithium in drinking water and the intake of lithium. However, other sources may be important. The determination of urinary lithium levels could represent an advance in addressing the issue of the possible protective effect of lithium concerning the tendency to suicide, by allowing a more realistic determination of lithium intake by the general population.
- Association entre les niveaux urinaires de lithium et le taux de suicide - une étude pilote dans le nord du PortugalPublication . Cainé, Laura; Santos, Agostinho; Almeida, Agostinho; Duro, Mary; Gonçalves, Carolina; Azevedo, Rui; Costa, FélixIntroduction: Plusieurs études ont révélé une relation inverse entre les niveaux de lithium dans l'eau potable et le taux de mortalité par suicide dans la population générale. Mais cette observation a échoué dans d'autres études, y compris au Portugal, notamment lorsque les niveaux de lithium sont plus faibles. La principale limite de ces études “écologiques” est qu’ils supposent une corrélation entre la concentration de lithium dans l'eau potable et l'apport de lithium aux personnes. Cependant, d'autres sources peuvent être importantes. La détermination des taux urinaires de lithium peut constituer une avancée dans l'étude de cette problématique, en permettant une évaluation plus réaliste des apports en lithium par la population générale. Matériel et méthodes: À l'aide de l'ICP-MS, les niveaux de lithium (et un large éventail d'autres éléments) ont été déterminés dans des échantillons d'urine d'individus de deux régions avec des taux de mortalité par suicide très différents (risque relatif 1,67 et 0,28, respectivement). Résultats (μg/L) – Région haute RR: n=51; moyenne: 37,6; écart type: 30,5; médian: 27,5; 5e percentile: 6,81; 95e percentile: 111,9. Région faible RR: n=131; moyenne: 54,5; écart type: 95,6; médian: 22,6; 5e percentile: 8,74; 95e percentile: 173,8. Conclusion: Les résultats ne permettent pas de conclure sur une association claire entre le lithium urinaire et le risque suicidaire. Cependant, la valeur moyenne était plus élevée dans la région à faible risque de suicide, où un pourcentage plus élevé de taux urinaires élevés a également été observé. L'étude doit continuer à englober un plus grand nombre d'individus.