DEMENTIA IN SOCIETY
Lancet Commission identifies 12 modifiable risk factors that could account for 40% of dementias In 2017, the Lancet Commission on dementia prevention, intervention and care identified nine modifiable risk factors which might contribute to a person’s risk of developing dementia. Their recent update, published this summer, adds three further risk factors to this list. We also speak to the lead author, Gill Livingston, and ask four experts to comment. Over the last three decades, the search for a drug that can effectively treat the underlying causes of dementia has been elusive, with few positive developments to report. However, despite the absence of an effective disease-modifying therapy, there is growing consensus that concrete steps can still be taken to reduce the risk of developing dementia. Indeed, according to the recent Lancet Commission on dementia prevention, intervention and care, modifiable risk factors may hold the key to lessening your chances of developing dementia. Defined as factors that can be reduced or controlled through altered behaviour, modifiable risk factors include lifestyle habits such as smoking, and treatable conditions such as type 2 diabetes. At the opposite end of the spectrum are unmodifiable genes such as ApoE4, and the most well-established risk factor for Alzheimer’s disease and dementia: increasing age. Encouragingly, a subgroup analysis of 1109 participants in the Finnish FINGER trial suggests that adopting healthy lifestyle habits may diminish the negative effect of ApoE4 on cognitive function, reinforcing the importance of understanding and addressing modifiable risk factors for dementia. So what are the key modifiable risk factors associated with dementia? In their original report, which was published in 2017, the
36  Dementia in Europe
Lancet Commission identified nine lifestyle habits and treatable conditions linked to increased worldwide dementia prevalence. In order of importance, these were hearing loss, less education, smoking, depression, physical inactivity, hypertension, social isolation, obesity and diabetes.
and lifelong educational attainment are less affected by dementia.
In midlife, hearing loss was shown to have the most substantial effect on dementia prevalence, potentially accounting for 8% of cases, followed by traumatic brain injury (3%) and hypertension (2%). Traumatic brain In their recent update to this report, Profes- injury (TBI), defined as injuries such as consor Gill Livingston and coauthors have added cussion or skull fracture, was added to the three more modifiable risk factors to this list: list based in part on findings from a Danexcessive alcohol consumption, traumatic ish population study of almost 3 million brain injury and air pollution. middle-aged adults, showing that people with a history of TBI were 24% more likely Midlife hearing loss associated with cog- to develop dementia. nitive decline Several modifiable risk factors were identified To identify these risk factors, the Lancet as having an impact in later life; in particular, Commission performed a comprehensive smoking (5%), depression (5%) may contribanalysis of hundreds of research studies ute substantially to dementia. Social isolation and publications, including the recent large- (4%) also has a substantial impact on demenscale FINGER, PreDIVA and MAPT trials on tia risk; in a UK 28-year follow-up study of multidomain interventions for cognitive over 10,000 older people, frequent social impairment. contact in late middle-age reduced the odds of developing dementia by 10%. Together, Studying risk factors at different stages these twelve risk factors across the lifecourse across the lifecourse, Professor Livingston may account for around 40% of worldwide and colleagues identified risk factors in dementias. early life, midlife and later-life that could be targeted by individual-level and policy The existence of potentially modifiable risk facinterventions. For example, maintaining tors for dementia has important ramifications: high levels of cognitive stimulation in early it means that prevention of dementia may life could reduce dementia risk by 7%, based in part be possible through a public health on robust evidence showing that those approach, via the implementation of lifestyle with higher childhood education levels interventions targeting these risk factors.
