Tackling 14 adjustable risk factors from childhood through to later life could significantly reduce the prevalence of dementia, potentially preventing or delaying nearly half of all cases. This approach is more critical than ever as populations age globally and dementia cases are expected to soar, as highlighted in the latest findings from the third Lancet Commission on dementia prevention, intervention, and care, presented at the Alzheimer’s Association International Conference (AAIC) 2024. The updated report introduces two additional risk factors associated with 9% of all dementia cases. Notably, around 7% of cases are linked to elevated levels of low-density lipoprotein (LDL) or “bad” cholesterol from midlife, around age 40, and 2% to untreated vision loss later in life. These join the previously identified 12 risk factors from the 2020 Lancet Commission, including lower educational attainment, hearing impairment, hypertension, smoking, obesity, depression, physical inactivity, diabetes, excessive alcohol intake, traumatic brain injury (TBI), air pollution, and social isolation, which collectively are associated with 40% of all dementia cases.

The report stresses that the most significant risk factors on a global scale are hearing impairment and high LDL cholesterol, each contributing to 7% of cases, followed by reduced early-life education and social isolation in later life, each at 5%. Authored by 27 leading global dementia experts, the Commission advocates for proactive measures across the lifespan to mitigate dementia risks, suggesting that early intervention could significantly enhance outcomes. With the global population ageing rapidly, projections indicate a near tripling of dementia cases by 2050, from 57 million in 2019 to 153 million, particularly affecting low-income nations where life expectancy is also increasing. This demographic shift underlines the urgent need for widespread action to lower dementia risks globally, as the associated health and social costs currently surpass $1 trillion annually.

Interestingly, some high-income countries, like the USA and the UK, have observed a decline in dementia prevalence among older adults, especially those in socio-economically advantaged areas. This trend is likely due to improved cognitive and physical resilience built over lifetimes and reduced vascular damage from better healthcare and lifestyle changes, reinforcing the importance of early preventive strategies. Despite these advances, most national dementia plans lack specific recommendations for addressing the needs of culturally and ethnically diverse populations who are disproportionately affected by dementia risks. The Commission’s new report underscores the pressing need for enhanced preventive efforts, mainly targeting vulnerable populations in low- and middle-income countries and socio-economically disadvantaged groups, to alleviate risk inequalities and promote accessible healthy lifestyles.

To combat dementia risks throughout life, the Commission lists 13 recommendations for governments and individuals, including ensuring quality education for all children, increasing access to hearing aids, managing high LDL cholesterol from midlife, providing widespread screening and treatment for vision impairments, effectively treating depression, promoting the use of protective gear in contact sports, fostering supportive community environments, implementing strict air quality policies, and intensifying measures to curb smoking. Professor Gill Livingston of University College London, the lead author, emphasizes adopting healthy lifestyles involving regular exercise, non-smoking, cognitive activities in midlife, and moderate alcohol consumption. Such lifestyles not only reduce dementia risks but could also delay the onset of dementia, thereby enhancing quality of life and generating substantial cost savings for societies.

Concurrently, a study published in The Lancet Healthy Longevity journal alongside the Commission’s report estimates that implementing effective population-level interventions in England could result in savings exceeding £4 billion and gain over 70,000 quality-adjusted life years (QALYs). The potential benefits could be even more significant in countries where public health interventions are not yet widespread. The Commission also discusses promising advancements in Alzheimer’s research, such as blood biomarkers and anti-amyloid β antibodies, while calling for more research and transparency regarding their long-term effects. Additionally, it advocates for increased support for people living with dementia and their caregivers, highlighting the need for more effective interventions and resources.

While much of the evidence on dementia originates from high-income countries, there is growing research from low- and middle-income countries, suggesting that while some risk factors may only be partly causal, comprehensive and culturally tailored interventions are essential for effectively managing and preventing dementia globally.

More information: Gill Livingston et al, Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission, The Lancet. DOI: 10.1016/S0140-6736(24)01296-0

Journal information: The Lancet