Modifying 12 risk factors over the course of one's life could delay or prevent 40 per cent of dementia cases, according to the latest verdict of The Lancet Commission on dementia prevention, intervention and care.
The commission has added three new “key modifiable risks factors” that make people more vulnerable to dementia; excessive alcohol consumption in mid-life, suffering head injuries in mid-life and exposure to air pollution in later life.
Led by 28 world-leading dementia experts, the report builds on the nine risk factors from childhood to later life identified in 2017, and provides an up-to-date analysis of the best evidence on the prevention of dementia. “The potential to prevent cases of dementia is high,” it adds.
Its latest report presented at the Alzheimer’s Association International Conference on Thursday calls of states and individuals to be ambitious about preventing dementia and lays out a set of policies and lifestyle changes to help prevent dementia.
Worldwide around 50 million people live with dementia, a figure projected to increase to 152 million by 2050, rising particularly in low-income and middle-income countries (LMICs) where around two-thirds of people with dementia live. Dementia affects individuals, their families, and the economy - with global costs estimated at about €1 trillion annually.
Combined, the three new risk factors are associated with 6 per cent of all dementia cases – with an estimated 3 per cent of cases attributable to head injuries in mid-life; 1 per cent of cases to excessive alcohol consumption (more than 21 units per week) in mid-life, and 2 per cent to exposure to air pollution in later life.
The remaining risk factors are associated with 34 per cent of all dementia cases. The factors associated with the greatest proportion of dementia cases in the population are less education in early life; hearing loss in mid-life, and smoking in later life (7 per cent, 8 per cent, and 5 per cent, respectively).
In certain countries, however, the proportion of older people with dementia has fallen, probably due to improvements in education, nutrition, healthcare, and lifestyle changes – demonstrating the possibility of reducing dementia through preventative measures, it concludes.
"Our report shows it is within the power of policy-makers and individuals to prevent and delay a significant proportion of dementia, with opportunities to make an impact at each stage of a person's life," says lead author Prof Gill Livingston of University College London, UK.
“Interventions are likely to have the biggest impact on those who are disproportionately affected by dementia risk factors, like those in low- and middle-income countries and vulnerable populations, including Black, Asian and Minority Ethnic communities,” he added.
Prof Livingston added: "As societies, we need to think beyond promoting good health to prevent dementia, and begin tackling inequalities to improve the circumstances in which people live their lives."
Risks could be reduced by creating active and healthy environments for communities, “where physical activity is the norm, better diet is accessible for all, and exposure to excessive alcohol is minimised”.
The authors call for nine ambitious actions to be undertaken by policymakers and individuals:
– Aim to maintain systolic blood pressure of 130 mm Hg (millimeters of mercury) or less in midlife from around age 40 years;
– Encourage use of hearing aids for hearing loss; reduce hearing loss by protecting ears from high noise levels;
– Reduce exposure to air pollution and second-hand tobacco smoke;
– Prevent head injury (particularly by targeting high-risk occupations and transport);
– Prevent alcohol misuse and limit drinking to less than 21 units per week;
– Stop smoking uptake and support individuals to stop smoking (which the authors stress is beneficial at any age);
– Provide all children with primary and secondary education;
– Lead an active life into mid, and possibly later life;
– Reduce obesity and diabetes.
These actions, they say, are especially important in LMICs such as China, India and Latin America, where dementia rates are rising more rapidly than in high-income countries. This is due to increasing life expectancy, and a higher frequency of dementia risk factors such as lower rates of education; high rates of hypertension, obesity, hearing loss and rapidly growing rates of diabetes.
The authors note they were careful to only include risk factors with strong evidence for a causal link.
Their report calls for holistic and individualised evidence-based care that addresses physical and mental health, social care, and support that can accommodate complex needs of those with dementia.
“Keeping people with dementia physically healthy is important for their cognition but they often have other illnesses which they may struggle to manage on their own, resulting in potentially harmful preventable hospitalisations,” it notes.
