The 2024 Lancet Commission on Dementia Prevention, Intervention, and Care published its report providing an updated analysis of the current evidence and recommendations for reducing dementia risk and improving care.
The Commission, comprising an international team of experts, identified 14 key modifiable risk factors and performed a new calculation of the population attributable fraction (PAF), estimating that these factors collectively contribute to approximately 45% of dementia cases worldwide.
The report incorporated two new risk factors: untreated vision loss and high LDL cholesterol. These were added to the 12 previously recognized factors, which included less education, hearing loss, hypertension, smoking, obesity, depression, physical inactivity, diabetes, excessive alcohol consumption, traumatic brain injury, air pollution, and social isolation.
Using a life-course model, the researchers calculated the potential impact of reducing these risk factors. Less education in early life contributed 7%, hearing loss in midlife 7%, and smoking in midlife 5%. Other significant contributors included social isolation in late life (5%), high LDL cholesterol in midlife (7%), and depression in midlife (3%).
The Commission performed new meta-analyses for depression and hearing loss. The risk of dementia was 2.25 times higher for those with depression 10-14 years prior compared to those without. For hearing loss, the risk was 1.37 times higher compared to those without hearing loss.
The report highlighted the disproportionate burden of dementia risk factors among disadvantaged populations. In the U.S., the prevalence of potentially modifiable risk factors was higher among Black (9.9%) and Hispanic (11.0%) individuals compared to White non-Hispanic individuals (7.7%).
The Commission emphasized the importance of timely diagnosis and care coordination. A meta-analysis of 12 randomized controlled trials found that antihypertensive medication was associated with a lower risk of dementia or cognitive impairment compared to placebo or higher blood pressure targets.
Cholinesterase inhibitors and memantine were recommended for the treatment of Alzheimer's disease and Lewy body dementia based on evidence of their effectiveness in reducing symptom severity, improving cognition, and decreasing mortality risk.
The report discussed the potential of disease-modifying treatments, such as amyloid-β-targeting antibodies, which showed modest efficacy in reducing cognitive decline in early Alzheimer's disease. However, the Commission cautioned about the limited generalizability of these findings, as most trials excluded participants with psychiatric illnesses, cerebrovascular disease, and cardiovascular disease.
Reducing vascular damage, dementia neuropathology, stress, and inflammation while increasing cognitive and brain reserve can help prevent and delay dementia. The report authors emphasized the importance of culturally tailored interventions for people with dementia and their caregivers, especially in low- and middle-income countries..
Lessons learned from the COVID-19 pandemic were also highlighted, as people with dementia experienced higher mortality rates compared to those without dementia.
The Commission called for urgent action to prioritize brain health across the life course and improve the lives of those affected by dementia through a combination of individual and population-level interventions, while acknowledging the limitations of current evidence and the challenges of implementing preventive strategies.
Declaration of interests can be found in the report.