For decades, the advice for protecting brain health has been remarkably consistent: stay physically active, eat a balanced diet, avoid smoking, control cardiovascular risk factors, remain socially connected and continue learning throughout life. Although this guidance remains one of the strongest evidence-based foundations for reducing dementia risk, a recent Nature feature highlights an important shift in dementia research. Rather than viewing risk factors as separate pieces of a checklist, researchers increasingly see them as part of an interconnected system shaped by biology, mental health, social circumstances and the environments in which people live. Healthy behaviors remain essential—but their benefits may depend on how they interact with many other aspects of health across the life course.
Recent research supports this broader perspective. A nationwide Danish study involving more than 1.7 million people estimated that nearly 38% of dementia cases could be linked to potentially modifiable risk factors. The study showed that these factors frequently reinforce one another. Depression, cardiovascular disease and hospital-diagnosed infections, for example, were associated with greater dementia risk when they occurred together than would be expected from considering each factor separately. Rather than independent contributors, they appear to form interacting networks of vulnerability.
An international study from The Lancet Health Longevity analyzing data from more than 214,000 participants across 14 countries reached a complementary conclusion. Although the prevalence of individual risk factors differed substantially between populations, more than half of participants had at least two modifiable risk factors, and similar patterns of clustering emerged across diverse settings. This suggests that prevention should continue to promote healthy lifestyles while also recognizing that risk is shaped by combinations of factors influenced by local social and healthcare contexts.
This evolving understanding is already influencing intervention research. Multidomain programs such as LatAm-FINGERS combine physical activity, nutritional guidance, vascular risk management and cognitive training, acknowledging that meaningful prevention is unlikely to rely on a single behavior alone. Instead, they seek to strengthen several protective pathways simultaneously while adapting interventions to different populations.
Staying active, eating well, managing cardiovascular health and maintaining social and cognitive engagement remain fundamental to healthy ageing. The difference is that researchers are beginning to understand these actions as interconnected rather than independent, embedded within wider systems that include mental health, education, healthcare access and the environments people inhabit. As evidence accumulates across many chronic diseases, prevention is increasingly moving from identifying individual risk factors to understanding how they interact throughout life. The next advance in public health may therefore come from connecting what we already know into more integrated, personalized and equitable strategies for lifelong health.
Coordinator at la Verneda-Sant Martí Learning Community and adjunct professor at the University of Barcelona