Assessing seasonal variation in mortality and its causes: a case study in Brazil

Comparing seasonal variations in mortality across regions is challenging due to differences in methodologies, including variations in modeling strategies and data availability. Most existing studies focus on temperate regions, with limited research on equatorial and tropical areas. To address this gap, we propose a new Peak Season Excess Death index (PSEDi), which accounts for climate differences across multiple latitudes. This index serves as an alternative to the traditional Excess Winter Death index and peak-to-trough ratio, offering a more adaptable approach for diverse climatic regions. Our study demonstrates the effectiveness of PSEDi in uncovering mortality seasonality trends across regions with varying climatic profiles and excess mortality periods. The proposed index performs well not only in areas where previous indexes have been applied but also in nontemperate regions such as Latin America, Africa, and Southeast Asia, providing a more comprehensive perspective on seasonal mortality patterns.