Dementia, disability and frailty in later life – mid-life approaches to delay or prevent onset

Context

This guideline is about mid-life approaches to reducing the risk of dementia, disability and frailty. It focuses on changes to modifiable risk factors that are shared with a number of other non‑communicable diseases, such as type 2 diabetes, cardiovascular disease, and some cancers. Risks for these conditions develop over the life course, so the beginnings of long‑term ill health can occur in mid‑life or even earlier. Although some people's risk will be determined by factors that can't be changed, such as inherited conditions or injury, many people's risk for dementia, disability and frailty may be reduced by changing specific risk factors and behaviours.

Age‑related change is inevitable: we all change as we get older. Some of these changes will be positive, such as in the greater skills and experience that come with education, employment or parenthood. Other changes, especially as we move through mid‑ and into later life, may be less positive. Reported adverse changes at mid‑life include the start of a decline in various cognitive functions (such as memory, reasoning and verbal fluency) by age 45 (Newman et al. 2011; Singh‑Manoux et al. 2011). An age‑related decline in walking speed has been observed after the age of 30 (Newman et al. 2011). Some limitations in mobility have been identified in 18% of men and 19% of women aged 50 to 64 in England. In this age group, 11% of men and 10% of women reported difficulties with 1 or 2 activities of daily living (Gardener et al. 2006). Although many of these changes are inevitable at some point in life, the age at which they affect people, and how much they go on to become more serious health issues, will vary.

Age‑related changes can be made worse by personal, social and environmental circumstances. For example, having to care for an elderly parent, can lead to a reduced income and less time for leisure activities.

Dementia, disability and frailty in later life affect individuals, families and society as a whole, and can cause reduced quality of life, ill‑health and premature mortality. They have a direct effect on community resources, because people are less able to do their usual daily activities and often need support and long‑term care. This impact is set to increase in the future as the population ages.

Dementia is something most people associate with Alzheimer's disease. It is generally thought that Alzheimer's disease accounts for 50–75% of dementia cases, with vascular dementia accounting for up to 20% (Dementia: a public health priority, World Health Organization and Alzheimer's Disease International). However, there is increasing evidence that individual cases of dementia are often due to a combination of Alzheimer's disease and vascular dementia. Vascular disease can be prevented, and so reductions in the incidence of vascular and mixed dementias may be expected to follow. Other forms of dementia, such as dementia with Lewy bodies and fronto‑temporal dementia, are much less common and less is known about how to reduce the risk of these.

Disability refers to any long‑term restriction on the ability to perform an activity in a normal way. This may be because of limited body function or structure, as a result of injury or disease, or personal or environmental factors. People often think of disability as difficulty walking, but problems using your hands, hearing loss, sight loss and speech impairment are just a few of the many issues people may experience which contribute to disabilities. The impact of these functional restrictions can be made worse by poor environments, but can made easier to cope with in good environments. For example, physical mobility can be made easier by improvements to the environment. Conditions such as type 2 diabetes, arthritis and cardiovascular disease, as well as obesity, are all associated with forms of disability.

Frailty can be either physical or psychological frailty, or a combination of the two, and can occur as a result of a range of diseases and medical conditions. This guidance uses the deficit model of frailty that adds up a person's impairments and conditions to create a measure of risk and severity (Morley et al. 2013). This model includes comorbidity and disability as well as cognitive, psychological and social factors. The potential causes are therefore wide, and multiple risk factors are implicated in the various diseases and conditions (Fit for Frailty, British Geriatric Society). Some of these risk factors are shared with the types of dementia and disability described above, and are amenable to change.

Several cohort studies have found links between successful ageing and a person never having smoked (or having quit), exercising regularly, eating fruit and vegetables daily and drinking only a moderate amount of alcohol. The EPIC‑Norfolk study found that people who adopted all these behaviours lived an average of 14 years longer than people who did none of them (Khaw et al. 2008). They also had more quality‑adjusted life years (Myint et al. 2011). In the Whitehall study, people who adopted all 4 behaviours were 3.3 times more likely to age successfully. The association with successful ageing was linear, with people who adopt healthier behaviours having a greater likelihood of successful ageing (Sabia et al. 2012). However, other risk factors such as social isolation can have an effect.

The Department of Health and Social Care's Chief Medical Officer annual report from 2011 notes that having more than 1 of the 7 'health risk' factors of smoking, binge drinking, low fruit and vegetable consumption, obesity, diabetes, high blood pressure and raised cholesterol is common in mid‑life. Among men, the proportion having 4 or more risk factors is greatest for those aged 55 to 64 (21.4%). Among women, the proportion with 4 or more risk factors is greatest in those aged 65 to 74 (16.2%).

Between 2003 and 2008, the greatest reduction in the number of adults in the general population displaying 4 behavioural risk factors (smoking, lack of physical activity, consuming alcohol, and poor diet) was seen in higher socioeconomic and more highly educated groups. People from unskilled households are more than 3 times more likely to adopt behavioural risk factors than people in professional groups (Clustering of unhealthy behaviours over time. Implications for policy and practice, The King's Fund's).

Life expectancy continues to increase in the UK, but this increase is not necessarily extra years spent in good health and free of disability. By 2035, it is estimated that 23% of the population will be aged 65 or over (Health expectancies at birth and age 65 in the United Kingdom, 2008–10, Office for National Statistics).

Estimates of life expectancy, healthy life expectancy and disability‑free life suggest that, on average, a man of 65 in the UK will live a further 17.8 years. But that will include 7.7 years of poor general health and 7.4 years with a limiting chronic illness or disability towards the end of their life. On average, a woman of 65 will live a further 20.4 years. But that will include 8.8 years of poor general health and 9.2 years with a limiting chronic illness or disability (Health expectancies at birth and age 65 in the United Kingdom, 2008–10).

The incidence of dementia increases with age. Increases in life expectancy and in the proportion of older people in the UK population suggest that dementia incidence would also rise. However, newer information suggests that the prevalence of dementia in 2011 was lower than had been predicted from early 1990s data. This finding is consistent with findings from other high income countries. The lower prevalence is attributed to a reduction in risk factors, for example smoking, and societal changes such as better education (Matthews et al. 2013).

However, in 2012 around 800,000 people in the UK were living with some form of dementia. More than 42,000 of these people were under 65. Family and friends were acting as primary carers for about 670,000 people. In 2014 the annual cost of dementia to the NHS, local authorities and families was estimated to be £26.3 billion (Dementia UK update 2014, Alzheimer's Society).

In 2012/13 it was estimated that more than 11 million adults in the UK were disabled. Of that total, 5.1 million were over the state pension age (for women this was 60 and over, for men 65 and over in 2012/2013) (Family resources survey UK 2012 to 2013, Department for Work and Pensions). Disabled adults in the UK are twice as likely to be living in poverty as non‑disabled adults. Disabled people's day‑to‑day living costs are 25% higher than those of non‑disabled people (Disability in the UK 2012, Papworth Trust).

Sensory disability, including hearing loss and visual impairment, is estimated to be responsible for 7% to 10% of all years lived with disability among those aged 70 or over in the UK (Chief Medical Officer annual report 2012: the public's health, Department of Health and Social Care). Some form of hearing loss is reported by 42% of people over 50 in the UK (Hearing matters, Action on Hearing Loss). An estimated 80,000 people of working age have a visual impairment (Evidence base to support the UK Vision Strategy, UK Vision Strategy). Both hearing loss and visual impairment have been associated with other health and social problems, including social isolation ('Hearing matters'; 'Evidence base to support the UK Vision Strategy'; Rogers and Langa 2010).

Frailty prevalence depends on the model of frailty used. A recent international systematic review of 31 studies of frailty in people living in the community aged 65 years or more found prevalence rates between 4 and 17% (mean 9.9%) of physical frailty using the phenotypic model. This uses 5 possible physical (phenotypic) markers – weight loss, exhaustion, weakness, slowness, and reduced physical activity. Prevalence was higher when using the broader deficit model (which includes psychosocial frailty), with rates between 4.2 and 59.1%. Women were almost twice as likely as men to be frail. The prevalence of frailty is markedly increased in persons older than 80 (Collard et al. 2012).

Having 2 or more chronic conditions (multimorbidity) is common among people aged 65 and older. However, there are more people under 65 than over 65 with multimorbidity (Barnett et al. 2012, Agborsangaya et al. 2012). Multimorbidity is associated with low socioeconomic status, and it can begin 10–15 years earlier in people living in the most deprived areas than in those living in the most affluent ones (Barnett et al. 2012). Multimorbidity is also associated with low educational attainment (Nagel et al. 2008). Therefore, risk reduction may need to occur earlier in life in some disadvantaged groups.