Risk Factors for Alzheimer's disease (AD)
Aging
Aging is still the largest risk for becoming demented, with the prevalence doubling every 5 years between ages 65 and 85 ( 1% at age 65, 5% at age 75 and 15-25% at age 85).
Family history of AD
Family history of dementia in a first degree relative ( sibling or parent) increases the risk of developing AD fourfold. In persons with two or more affected first degree relatives, the risk increases 7-8 fold. The mechanism is presumably due to the higher risk of transmitting one or more alleles which accelerate the pathogenetic mechanisms involved in AD.
Family history of Down syndrome
A family of history of Down syndrome may increase the risk for developing AD by two-to-three fold. The persons without Down syndrome who have developed AD in these families did not have triplication of chromosome 21.
History of depression
A history of depression more than 10 years prior to the onset of AD approximately doubles the risk. The mechanism is unknown, but the reduced activity of frontal and temporal lobes in depression may make these areas more vulnerable to pathological mechanisms.
Estrogen deficiency
Estrogen deficiency in postmenopausal women has been implicated in a variety of studies as increasing the risk of AD and possibly other dementias. This has been demonstrated mostly through studies of hysterectomized (including ovaries) women. The mechanism of action may be through estrogen's influence on nerve growth factor, which supports acetyl choline-secreting neurons that are severely affected in AD.
Lack of education
An uneducated person has about twice the risk of developing dementia due to AD or vascular disease by age 75 when compared to someone with at least an 8th grade education. The mechanism of this effect may be synaptic strengthening of frequently used brain regions ( use-dependent plasticity), which may also explain why some persons with specific talents or hobbies, such as golf, playing music, playing cards, drawing cartoons show preservation of such highly used skills even if they develop AD.
HEAD TRAUMA
Either severe single head injuries producing prolonged unconsciousness, or repeated head injuries approximatly double the risk for AD. The mechanism may relate to increased expression of PS-1 gene products and to increased production of diffuse beta amyloid following trauma. An increased pool of diffuse, soluble beta amyloid may increase the opportunity for the formation of insoluble beta amyloid, which is known to be neurotoxic and known to be present in neuritic plaques, one of the hallmarks of AD neuropathology.
Other possible risks for AD
Other factors which may increase the risk for AD include:
- A history of increased alcohol consumption.
- A history of heart attack especially in women (vascular dementia AD). The mechanism may be due to increased production of diffuse beta-amyloid plaques.
- Maternal age over 40.
- Family history of Parkinson's disease.
- hypothyroidism
Topics:
Given the reduced risk of AD for persons with at least 8 years of education, it is reasonable to recommend active, regular use of thinking skills such as reading, writing and arithmetic. For example, research in the area of use-dependent plasticity has shown that persons who use language skills have larger, more elaborate connections in the areas of the brain related to language function. Also, we routinely see, clinically, patients with AD who have particular talents that are well preserved until moderately demented.
The exact cause of Alzheimer's Disease, a form of dementia, is still unknown. However, scientists have been able to indentify several contributing factors. Alzheimer's Disease is known to have a genetic componant as well as an environmental one. While Alzheimer's is a form of dementia, dementia is not necessarily Alzheimer's. There are many forms of demetia, some which are entirely curable. It is imporatant to understand the distinction between Alzheimer's disease and dementia.
If you are approaching the menopause, discuss the risks and benefits of estrogen replacement therapy with your doctor. Administered over a period of years, estrogen can relieve unpleasant symptoms related to reduced estrogen levels. For women at high risk of osteoporosis, long-term therapy substantially reduces the chances of bone fracture. In addition, some studies show that estrogen lowers the risk of cardiovascular disease, and some evidence suggests that women taking estrogen suffer from depression less often.
Dementia is a general term that includes specific disorders such as Alzheimer's disease, Vascular or Multi-infarct dementia, Pseudodementia, and others. Dementia is defined as a loss in at least two areas of complex behavior, such as language, memory, visual and spatial abilities, or judgment, that significantly interferes with a person's daily activities.
Dementia affects over 4 million Americans, is the 4th major cause of death, and costs society $100 billion annually.
Causes
There are different causes of cognitive dysfunctions, i.e. memory - short & long term, concentration, language, speech, visuo-spatial orientation. Most of them are nearly irreversible condition such as Alzheimers Disease, Multi- Infract Dementia, Lewy Body Disease, Picks Disease, Parkinson's Disease, Huntingtons Disease etc. Among them Alzheimers Disease is the most common cause of degenerative dementia. It is a debilitating, life-altering disease that attacks the brain.
Almost everyone-experiences some decline in memory and reaction time after age 40. But a rich network of neural connections-links between brain cells that allow them to communicate-can help compensate for these losses.
A rich neural network may even help keep people from being incapacitated by Alzheimer's disease.
Extensive neural connections seem to act as a kind of cognitive reserve allowing a person to function longer with the disease than someone whose mental resources were less extensive.
Good News:
Behavioral problems commonly coexist with cognitive deficits during the course of Alzheimer's and other dementing diseases. They cause significant morbidity, interfere with the performance of activities of daily living, and often have a greater impact on the quality of life of family and caregivers than cognitive impairment.
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