Geographical Variations in Metal Exposure and Its Impact on Metabolic Disorders and Hypertension: An Analysis of Chile's 2016–17 National Health Survey

Background Evidence suggests that even low-level exposure to metals may disrupt metabolic pathways, contributing to metabolic disorders. Local environmental factors may modulate these effects, emphasizing the importance of territorial disaggregation. This population-based study evaluated geographic variations in exposure to four metals and their associations with obesity, diabetes, metabolic syndrome, and hypertension in Chile. Method Data from 3,822 participants in the National Health Survey from 2016 to 2017 were analyzed. Biomarkers included inorganic arsenic, cadmium, mercury in urine, and lead in serum. Metal exposure was classified according to the 50th percentile distribution. Spatial simultaneous autoregressive models accounted for regional disaggregation and spatial dependencies, adjusting for age, sex, socioeconomic status, and smoking. Analyses were conducted at the national and subnational levels, incorporating sampling weights from the national survey complex design. Results A total of 42.4% of individuals were exposed to arsenic, 13.6% to lead, and 1.7% to mercury and cadmium. Regional analysis revealed elevated arsenic exposure in northern regions (e.g., Arica and Antofagasta), with lead exposure peaking at 29.9%. At the national level, adjusted models revealed no significant associations between metal exposure and metabolic disorders. However, geographical disaggregation revealed that arsenic exposure was linked to overweight and obesity across most areas and to diabetes and metabolic syndrome in the northern, southernmost, and central zones. Mercury exposure was associated with all conditions in the central macrozone, whereas cadmium exposure was exclusively linked to diabetes in southern regions. Conclusion These findings underscore critical regional differences in metal and metalloid exposure and metabolic disorders, highlighting the need for geographically targeted public health interventions that consider local environmental and contextual factors. Trial registration Not applicable