Supplemental Material for:Temporal Heterogeneity and Driving Factors of Idiopathic Epilepsy Incidence in BRICS Countries: A Population-Based Age–Period–Cohort Analysis

APC analysis revealed incidence rates increased in all BRICS countries (net drift > 0) except South Africa. Local drift generally followed an age-stratified pattern, fluctuating in individuals aged 0–64 years and rising in those aged 65–100. Gender differences were notable: incidence increased more rapidly in Chinese males than females, whereas in Russia, local drift peaks differed by sex among individuals aged ≥65 years.

All BRICS countries exhibited a bimodal age effect. Period effects showed an inflection in Brazil around 2009–2014, a continuous increase in India, and relative stability in the remaining countries. Cohort effects rose gradually in India, followed a “rise-then-fall” pattern in Russia, were lower in South Africa, higher in China, and stable in Brazil.</b></p><p dir="ltr"><b>Conclusions: </b>Idiopathic epilepsy incidence in BRICS countries demonstrates significant heterogeneity.

Temporal trends are shaped by perinatal health, demographic changes, healthcare improvements, and sociocultural factors. Targeted interventions for high-risk populations are critical to reduce disease burden and optimize resource allocation.</p>