AAIC 2026: Dementia risks differ sharply across countries, but key patterns persist

Clinical takeaway: Assess multiple modifiable dementia risk factors together rather than in isolation. While the most common risks vary by region, cardiovascular, behavioral, and sensory/social risk factors frequently cluster, creating opportunities for multidomain prevention strategies.

Most dementia-prevention evidence comes from high-income countries, but this study suggests that the prevalence of modifiable dementia risk factors varies substantially worldwide, potentially requiring country-specific prevention approaches.

In a harmonized cross-national analysis published in The Lancet Healthy Longevity and presented at the Alzheimer’s Association International Conference (AAIC) 2026, investigators evaluated 12 modifiable dementia risk factors among 214,251 adults aged 50 years and older across 14 countries and regions spanning North America, Europe, Latin America, and Asia.

The prevalence of individual risk factors varied markedly between settings. Low educational attainment affected nearly 86% of older adults in China but only 12% in the US, while obesity was present in about 45% of US participants compared with 13% in India. Hypertension and smoking consistently ranked among the most common risk factors across most countries, whereas low education was especially prevalent in many low- and middle-income countries.

Despite these differences, risk factors frequently occurred together. More than half of participants in every country had at least two dementia risk factors, and in 11 of 14 countries or regions, more than 20% had four or more. Cardiometabolic risks such as hypertension, diabetes, high cholesterol, and obesity commonly clustered together, as did smoking and alcohol use, and sensory/social factors including hearing loss, vision loss, and low education.

Patterns also varied by age, sex, and education level, although not always consistently across countries. Depression and social isolation were generally more common in women, while many risk factors were more prevalent among people with lower educational attainment.

Lead author Emma Nichols noted: “I was less surprised by the differences and more surprised by some of the similarities, particularly in the ways these risks are patterned across settings.” She added that these findings have “real implications for how we design prevention strategies and interventions.” The authors conclude that effective dementia prevention will likely require both locally tailored approaches and shared multidomain strategies that target common risk-factor clusters.

Source: Nichols E, et al. (2026 July 12) Lancet Healthy Longev. Differences in the prevalence and patterns of dementia risk factors across 14 countries and regions: a harmonised cross-national analysis