Burden of disease

Dementia is one of the main causes of disability in later life. In a wide consensus consultation for the World Health Organization’s Global Burden of Disease report, disability from dementia was accorded a higher weight than that for almost any other condition, with the exception of spinal cord injury and terminal cancer. Of course, older people are particularly likely to have multiple health conditions – chronic physical diseases affecting different organ systems, coexisting with mental and cognitive disorders. Dementia, however, has a disproportionate impact on capacity for independent living. Still its global public health significance continues to be under-appreciated and misunderstood. According to the 2003 World Health Report Global Burden of Disease estimates, dementia contributed 11.2% of all years lived with disability among people aged 60 and over; more than stroke (9.5%), musculoskeletal disorders (8.9%), cardiovascular disease (5.0%) and all forms of cancer (2.4%).We estimate that there are now 683,597 people with dementia in the UK. This represents one person in every 88 (1.1%) of the entire UK population. This is probably a very slight underestimate as it may not comprehensively include people with learning disabilities or people with dementia in NHS continuing care facilities.The total number of people with dementia in the UK is forecast to increase to 940,110 by 2021 and 1,735,087 by 2051, an increase of 38% over the next 15 years and 154% over the next 45 years.• Early onset dementia is comparatively rare, accounting for 2.2% of all people withdementia in the UK. We estimate that there are now at least 15,034 people with earlyonset dementia (onset before the age of 65 years) in the UK and 668,563 people withlate onset dementia (onset after the age of 65 years). However, given that data on the numbers of early onset cases are based on referrals to services, this number is likely to be an underestimate. The true figure may be up to three times higher.• The numbers of people with late onset dementia continue to rise for each five-yearage band up to the age of 80–84, and decline thereafter. Despite this, two-thirds(68%) of all people with dementia are aged 80 and over, and one sixth (17%) aged90 or over.• Overall we estimate that 222,925 men and 445,641 women have late onset dementia,approximately two women for every man affected. Both the higher mortality amongmen and the higher age-specific dementia prevalence in women contribute to the preponderanceof women among the ‘oldest-old’ with dementia.Dementia subtypes• We estimate that 416,967 people with dementia (62%) have Alzheimer’s disease (AD),the most common form of dementia. The next most common subtypes are vasculardementia (VaD) and mixed dementia, accounting for nearly one third (27%) of allcases.• The distribution of subtypes is different in men and women. Alzheimer’s disease ismore common in women (67% in women compared with 55% in men), while vasculardementia and mixed dementias account for 31% of all cases in men and just 25% inwomen. Severity of dementia• Among those with late onset dementia, 370,283 (55.4%) have mild dementia, 214,638(32.1%) have moderate dementia and 83,801 (12.5%) have severe dementia.• The proportion considered to have severe dementia increases with increasing age, from 6.3% for those aged 65 to 69 years to 23.3% for those aged 95 years and over. Institutional care• We estimate that 424,378 people with late onset dementia (63.5%) live in privatehouseholds (the community), whereas 244,185 (36.5%) live in care homes.• The proportion of those with dementia living in care homes rises steadily with age, from 26.6% of those aged 65–74, to 60.8% of those aged 90 and over. Historically, a lack of attention from policy makers and service commissioners to the needs of people with dementia has led to dementia care being delivered piecemeal and in an inefficient fashion. More investment accompanied by careful planning will be needed in the years ahead in order to ensure that not only do we maximise quality of life for people with dementia and their families, but also that we do so in an efficient way with the resources available.