Gonçalves Carolina, Azevedo Rui, Couto Cristina, Duro Mary, Santos Agostinho, Cainé Laura, Almeida Agostinho
Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal.
LAQV/REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal.
Nutrients. 2025 Apr 7;17(7):1283. doi: 10.3390/nu17071283.
: Higher lithium (Li) levels in drinking water have been linked to lower suicide rates in the general population in several ecological studies, though this relationship is not always consistent. The main limitation of such studies is the assumption that Li content in drinking water is directly correlated with total Li intake, which may not always be the case for several reasons. : In this context, we conducted a biomonitoring study to compare urinary Li levels-assumed as a reliable indicator of total Li intake-among individuals from three regions with different suicide relative risks (RRs): Porto Metropolitan Area (PMA; low RR), Central region (CT; intermediate RR), and Trás-os-Montes region (TM; high RR). Each participant provided a urine sample (first morning) and two water samples (drinking water and environmental water). Li concentrations were determined using ICP-MS. : A total of 311 individuals participated in this study. The median (P25-P75) urinary Li concentration was 21.9 (15.1-46.0) in PMA, 19.0 (12.6-30.4) in CT, and 24.2 (14.6-38.7) µg/L in TM, with no statistically significant differences between regions (Kruskal-Wallis test with Bonferroni correction). Urinary Li was weakly correlated with Li in drinking water (ρ = 0.174; = 0.002) but not with Li in environmental water (ρ = -0.036; = 0.694). : These findings do not support a protective role of natural Li exposure in suicide risk at the low levels found in drinking (P75 = 3.75 µg/L) and environmental (P75 = 6.87 µg/L) water. More robust and comprehensive biomonitoring studies are needed to clarify the potential impact of natural Li exposure on suicide rates.
在多项生态学研究中，饮用水中较高的锂（Li）含量与普通人群较低的自杀率相关，不过这种关系并不总是一致。此类研究的主要局限性在于假定饮用水中的锂含量与锂的总摄入量直接相关，而由于多种原因，情况未必总是如此。
在此背景下，我们开展了一项生物监测研究，以比较来自三个自杀相对风险（RR）不同地区的个体的尿锂水平（假定为锂总摄入量的可靠指标）：波尔图都会区（PMA；低RR）、中部地区（CT；中等RR）和特拉索斯-蒙特斯地区（TM；高RR）。每位参与者提供一份尿样（晨尿）和两份水样（饮用水和环境水）。使用电感耦合等离子体质谱法（ICP-MS）测定锂浓度。
共有311人参与了本研究。PMA地区尿锂浓度中位数（P25-P75）为21.9（15.1-46.0）μg/L，CT地区为19.0（12.6-30.4）μg/L，TM地区为24.2（14.6-38.7）μg/L，各地区之间无统计学显著差异（经Bonferroni校正的Kruskal-Wallis检验）。尿锂与饮用水中的锂弱相关（ρ = 0.174；P = 0.002），但与环境水中的锂不相关（ρ = -0.036；P = 0.694）。
这些研究结果并不支持在饮用水（P75 = 3.75μg/L）和环境水（P75 = 6.87μg/L）中发现的低水平天然锂暴露对自杀风险具有保护作用。需要开展更有力和全面的生物监测研究，以阐明天然锂暴露对自杀率的潜在影响。
