Nearly half of dementia cases preventable by tackling 14 risk factors

Nearly half of dementia cases could be prevented or delayed by addressing 14 modifiable risk factors starting from childhood, including two new risk factors – high LDL-cholesterol (LDL-C) level and untreated vision loss – according to a report of the 2024 Lancet Commission on dementia.

Recent evidence reveals that the two new risk factors contribute to 9 percent of all dementia cases, with high LDL-C in midlife contributing to 7 percent of the cases and untreated vision loss in late life contributing to 2 percent of the cases, respectively. These two new risk factors are added to the 12 risk factors previously identified in the 2020 report, which were linked to approximately 40 percent of all dementia cases. [Lancet 2024;doi:10.1016/S0140-6736(24)01296-0; Lancet 2020;396:413-446]

"Evidence is increasing and is now stronger than before for tackling the many risk factors for dementia that we modelled previously, including lower levels of education, hearing impairment, high blood pressure, smoking, obesity, depression, physical inactivity, diabetes, excessive alcohol consumption, traumatic brain injury, air pollution, and social isolation," noted the authors. 

Out of the 14 risk factors, hearing impairment and high LDL-C were linked to the greatest proportion of dementia cases (both 7 percent), followed by less education in early life and social isolation in later life (both 5 percent).

As life expectancies increase, the global incidence of dementia is estimated to nearly triple by 2050, soaring from 57 million cases in 2019 to an estimated 153 million cases in 2050. The most significant increases are expected in low- and middle-income countries. In contrast, high-income countries showed a downward trend in dementia cases, likely due to healthcare advancements and lifestyle changes. [Lancet Public Health 2022;7:e105-e125; Lancet Glob Health 2020;8:e524-e535; Neurology 2020;95:e519-e531; Lancet 2024;doi:10.1016/S0140-6736(24)01296-0]

According to an economic modelling study in England, population-level interventions to tackle excess alcohol consumption, brain injury, air pollution, smoking, obesity, and hypertension would help reduce life-course dementia risk and achieve cost-savings of >£4 billion, with >70,000 quality-adjusted life-years gains. The potential benefits may be even greater in low- and middle-income countries where population-level interventions, such as public smoking bans and compulsory education, are not already in place.

“Our new report reveals that much more can and should be done to reduce the risk of dementia. It is never too early or too late to take action – there are opportunities to make an impact at any stage of life,” said lead author Professor Gill Livingston of the University College London, UK.

The report outlines these recommendations for individuals and governments to help reduce dementia risk:

• Provide all children with good quality education.
• Be cognitively active in midlife.
• Make hearing aids available for all individuals with hearing loss and reduce harmful noise exposure.
• Detect and treat high LDL-C from approximately 40 years of age.
• Make screening and treatment for vision impairment accessible for all.
• Treat depression effectively.
• Wear helmets and head protection in contact sports and on bikes.
• Prioritize supportive community environments and housing to increase social contact.
• Reduce exposure to air pollution through strict clean air policies.
• Expand measures to reduce smoking, such as price control, raising the minimum purchase age, and smoking bans.
• Reduce sugar and salt content in food sold in stores and restaurants.