Will dementia hamper healthy ageing?

Abstract

During Jan 24–29, 2022, the 150th session of the WHO Executive Board will be held, and members will agree upon the agenda and resolutions to be considered by the World Health Assembly. An important initiative will be presented as part of so-called Pillar 3 (1 billion more people enjoying better health and wellbeing): healthy ageing. In December, 2020, the UN General Assembly declared 2021–30 the Decade of Healthy Ageing, and WHO is tasked to coordinate this initiative and provide strategic leadership on demographic change and healthy ageing. Today, there are more than 1 billion people aged 60 years or older. Around the world, populations are ageing and this demographic transition will affect almost all aspects of society. One condition, in particular, could well challenge WHO's and the UN's ambitions: dementia. Dementia is one of the major causes of disability and dependency among older people and, according to the Global Burden of Disease (GBD) study published in this issue of The Lancet Public Health, dementia cases are projected to triple by 2050 unless countries address risk factors. In their study, Emma Nichols and collaborators forecast dementia prevalence in 204 countries and territories and examine the impact of expected trends in exposure to selected, important risk factors. Nichols and colleagues estimate that the number of adults living with dementia worldwide is expected to increase from an estimated 57 million in 2019 to 153 million in 2050, due primarily to population growth and population ageing. The authors considered four risk factors for dementia—high blood sugar, smoking, obesity, and low education—and their potential effect on future trends, and report that improvements in education could reduce dementia prevalence by 6·2 million cases by 2050, but this could be countered by projected trends in obesity, high blood sugar, and smoking, which are expected to contribute an additional 6·8 million dementia cases. Moreover, dementia cases are projected to increase in every country, but there are substantial geographical heterogeneity and important differences in the estimated changes in age-standardised prevalence across Socio-demographic Index quintiles. This study is particularly important for several reasons. First, for policy locally. Country-level estimates can be used to inform national planning and decision making to ensure resources and support are available for individuals, carers, and health systems. Second, for prevention and the importance of potentially modifiable risk factors. The 2020 Lancet Commission on dementia estimated that 40% of dementia cases could be prevented or delayed if exposure to 12 known risk factors were eliminated: high blood pressure, smoking, obesity, low education, depression, diabetes, physical inactivity, hearing impairment, social isolation, excessive alcohol consumption, head injury, and air pollution. Tackling these risk factors goes well beyond individuals' behaviours and will need addressing the economic and social determinants of health. For Theo Vos, coauthor of the study, ”Ensuring that structural inequalities in access to health and social care services can be addressed and that services can additionally be adapted to the unprecedented needs of an increasing older population with complex care needs will require considerable planning at both local and national levels.” Finally, this GBD study provides a stark reminder that such growth in the number of individuals living with dementia underscores the need for very strong public health responses. In September, 2021, WHO reported on the progress of the public health response to dementia—as part of the Global Action Plan (2017–25), which aims to decrease the burden of dementia and improve the lives of individuals living with dementia and their carers. Halfway through this plan, some progress has been made, but too few countries have a national plan to prevent, mitigate, and manage dementia. For Hilary Evans, Chief Executive of Alzheimer's Research UK, “Dementia doesn't just affect individuals, it can devastate whole families and networks of friends and loved ones. The heart-breaking personal cost of dementia goes hand-in-hand with huge economic and societal impacts, strengthening the case to governments across the world to do more to protect lives now and in the future.” Dementia is a major and rapidly growing threat to healthy ageing and social care systems in every country. Investing in an adequate public health response to dementia and healthy ageing, with health equity at its core, needs to start now. Dementia prevention, intervention, and care: 2020 report of the Lancet CommissionThe number of older people, including those living with dementia, is rising, as younger age mortality declines. However, the age-specific incidence of dementia has fallen in many countries, probably because of improvements in education, nutrition, health care, and lifestyle changes. Overall, a growing body of evidence supports the nine potentially modifiable risk factors for dementia modelled by the 2017 Lancet Commission on dementia prevention, intervention, and care: less education, hypertension, hearing impairment, smoking, obesity, depression, physical inactivity, diabetes, and low social contact. Full-Text PDF