Understanding which dementia risk factors dominate in which populations could fundamentally reshape how prevention resources are allocated worldwide — a question that has been largely unanswered at a truly global scale until now. Rather than treating dementia prevention as a one-size-fits-all problem, this large cross-national analysis reveals that the burden of modifiable risk is distributed very differently depending on geography, income level, and likely cultural context.
Published in The Lancet Healthy Longevity, the harmonised analysis spans 14 countries and regions, examining the prevalence and co-occurrence of established modifiable dementia risk factors — including hypertension, obesity, physical inactivity, depression, diabetes, smoking, hearing loss, low social contact, and low education. The key finding is a dual signal: while the specific leading risk factors differ meaningfully across settings (for example, low education predominating in lower-income regions versus cardiovascular-linked factors in higher-income ones), the way risk factors cluster together within individuals follows broadly consistent cross-national patterns. This clustering consistency suggests that multidomain interventions targeting interconnected risk factor groups may retain efficacy even when transported across different national contexts.
This work builds on the influential Lancet Commission frameworks (2017, 2020, 2024) that identified up to 14 modifiable risk factors collectively accounting for roughly 45% of dementia cases globally. What this new harmonised analysis adds is empirical granularity about heterogeneity — something the Commission reports acknowledged but could not fully quantify. The clustering finding is particularly actionable: it suggests that programs simultaneously targeting cardiometabolic risk and social or cognitive engagement may address the highest-burden factor combinations almost regardless of national setting. Key limitations include reliance on cross-sectional self-reported data in several cohorts, probable differences in diagnostic ascertainment across countries, and the challenge of ensuring true harmonisation across datasets with varying methodologies. Still, the scope and rigor represent a meaningful step toward genuinely context-informed dementia prevention policy.
