Indirect costs include the cost of informal care and the loss in productivity of informal caregivers.In the United States as of 2019, informal (family) care is estimated to constitute nearly three-fourths of caregiving for people with AD at a cost of  US$234 billion per year and approximately 18.5 billion hours of care. The cost to society worldwide to care for individuals with AD is projected to increase nearly ten-fold, and reach about US$9.1 trillion by 2050.Costs for those with more severe dementia or behavioral disturbances are higher and are related to the additional caregiving time to provide physical care. Caregiving burden
The role of the main caregiver is often taken by the spouse or a close relative. Alzheimers disease is known for placing a great burden on caregivers which includes social, psychological, physical, or economic aspects. Home care is usually preferred by people with Alzheimers disease and their families. This option also delays or eliminates the need for more professional and costly levels of care. Nevertheless, two-thirds of nursing home residents have dementias.Dementia caregivers are subject to high rates of physical and mental disorders. Factors associated with greater psychosocial problems of the primary caregivers include having an affected person at home, the carer being a spouse, demanding behaviors of the cared person such as depression, behavioral disturbances, hallucinations, sleep problems or walking disruptions and social isolation.
In Alzheimers disease, tau undergoes chemical changes, becoming hyperphosphorylated; it then begins to pair with other threads, creating neurofibrillary tangles and disintegrating the neurons transport system. Pathogenic tau can also cause neuronal death through transposable element dysregulation. Disease mechanism
Exactly how disturbances of production and aggregation of the beta-amyloid peptide give rise to the pathology of Alzheimers disease is not known. The amyloid hypothesis traditionally points to the accumulation of beta-amyloid peptides as the central event triggering neuron degeneration. Accumulation of aggregated amyloid fibrils, which are believed to be the toxic form of the protein responsible for disrupting the cells calcium ion homeostasis, induces programmed cell death (apoptosis). It is also known that Aβ selectively builds up in the mitochondria in the cells of Alzheimers-affected brains, and it also inhibits certain enzyme functions and the utilisation of glucose by neurons.Various inflammatory processes and cytokines may also have a role in the pathology of Alzheimers disease. Inflammation is a general marker of tissue damage in any disease, and may be either secondary to tissue damage in Alzheimers disease or a marker of an immunological response. There is increasing evidence of a strong interaction between the neurons and the immunological mechanisms in the brain. Obesity and systemic inflammation may interfere with immunological processes which promote disease progression.Alterations in the distribution of different neurotrophic factors and in the expression of their receptors such as the brain-derived neurotrophic factor (BDNF) have been described in Alzheimers disease.