The respiratory health paradox in mato grosso seniors: environmental drivers of divergent hospitalization and mortality trends

Abstract Respiratory diseases remain a major public health concern and are particularly critical among older adults. In Brazil, limited spatiotemporally resolved evidence has constrained understanding of how environmental conditions co-vary with respiratory morbidity and mortality. We assessed spatiotemporal variability in hospitalization and mortality rates due to respiratory diseases among individuals aged ≥ 65 years in Mato Grosso, Central Brazil, from 2000 to 2020, and their ecological associations with key meteorological and environmental indicators. Hospitalizations and deaths recorded in the Brazilian Unified Health System (SIH/SUS) were integrated and aggregated to the municipal-month scale with precipitation (ERA5), relative humidity (ERA-Interim), active fire detections (hotspots), and PM2.5 (CAMS reanalysis). Analyses included bootstrapping, cross-correlation functions to characterize lag structures, and Local Moran’s I to identify spatial clusters. We found a respiratory health paradox: hospitalization rates declined over time while mortality increased, with patterns varying across spatial scales. At the state level, correlations with fire/PM2.5 proxies were weak and sometimes counterintuitive under aggregation, whereas localized clusters showed stronger positive co-variation during the dry season. This heterogeneity suggests that environmental drivers and respiratory outcomes interact differently across Mato Grosso, likely modulated by climatic gradients and healthcare access disparities. The findings support geographically targeted interventions integrating environmental monitoring, air-quality management, and health-system preparedness for older adults.