[SOUND] Hello, I'm Miia Kivipelto. I'm professor and clinical geriatrics at Karolinska Institute and the head of the Ageing epidemiology Research Unit at Imperial College London. In this lecture, we will focus on the etiology and epidemiology of dementia. Dementia is a syndrome and umbrella term used to describe the symptoms of a group of diseases that impair memory, behavior and thinking. Dementia is a general term for a decline in mental ability severe enough to interfere with daily life. Dementia is mainly affects all the people. However, it is not a normal part of age. In fact, it's one of the major causes of disability and dependency among all the people worldwide. Alzheimer's disease or AD is the most common type of dementia and may contribute to 60 to 70% of cases, but there are also several other courses. Especially among all the person so-called mixed dementia is also common. Meaning that several brain changes contribute to the development of dementia. So how do we define dementia? When considering cognitive impairment, one of the biggest issues is that there is not a clear dividing line between healthy cognitive function and dementia. There is cognitive continuum and spectrum of cognitive abilities as people age. This has given rise to a whole range of terms for various stages in between cognitive health and dementia. For example, subjective memory complaints, objective cognitive decline and mild cognitive impairment to dementia. Interestingly, a lot, but of all the people report subjective memory complaints. Meta-analysis results show that around 40% of all the people without dementia will say that they experience some difficulties with their memory and they memory is not what it works. Individuals with these subjective memory complaints are slightly more likely to go on to develop cognitive decline and dementia. Similarly, there is a thin line between the objective quantity of decline stage and what is considered cognitively healthy. This may include various cognitive domains, such as memory executive functions or speed of cognitive processing. What causes dementia? Different types of diseases can contribute to development of cognitive impairment and dementia. First, there are never degenerative diseases, such as Alzheimer's disease, Lewy body dementia and frontotemporal dementia which can cause dementia. These progressive diseases, all primary effect neurons or specific subsets of neurons in specific brain areas. Second, vascular dementia and vascular cognitive impairment are caused by reduced blood flow to the brain typically after a stroke. For example, there are different types of infarcts, pleadings and white matter lesions. Third, dementia can be due to treatable diseases, such as toxic disorders, depression and infectious. These conditions are very important to recognize and read before there is a permanent brain damage with different types of dementia, and the spectrum of symptoms diagnosing dementia can be difficult. Let's use the example of Alzheimer's disease is the most common form of dementia. However, the courses and mechanisms of AD are not yet entirely clear. A combination of imaging blood and cerebral spinal fluid test for various biomarkers can AD diagnosis together with clinical examination, and cognitive assessment. However, the tricky thing is that there is no single test for 80 instead. A diagnosis is based on a combination of assessments. Several studies have shown that positive AD biomarkers proceed clinical dementia. There are new diagnostic criteria that are mainly still for research purposes. But for the first time, we are using biomarkers for awesome pre-clinical AD. However, experts do not yet agree on whether or not and how early is possible to start diagnosing ad only based on biomarkers further, because someone has AD neuropathology. It does not mean they have clinical AD and they were also our typical clinical presentations. Therefore, we still need more validation studies to identify the value of these new developments, but very exciting times ahead. What is the global epidemiology of dementia and where are we heading in the future? Dementia is now the leading cause of death in the UK. Age is still the strongest risk factor for dementia. Research shows both dementia prevalence and incidence increase exponentially with age, with the most rapid increase affecting all this old 85 plus. Every three seconds someone in the world develops dementia. There were approximately 50 million people living with dementia in 2015. But by 2050, the number is expected to grow to 150 million. This is a huge increase mainly related to the fact that we are living longer. The largest increase in dementia prevalence will happen in low and middle income countries. Dementia is an overwhelming problem not only for the people who have it, but also for the caregivers and families. It is also a huge economic burden in 2018. The worldwide cost of dementia were 1 trillion US dollars. This estimate includes cost via informal care provided by family and friends. Social care also known as Community Care and Medical Care. With dementia expected to increase, these economic and social costs will increase dramatically too. To conclude, because of all these factors, dementia is now recognized as a public health priority. So what can we do about dementia? You will find out more in an upcoming lecture. [MUSIC]
