Mixed dementia is the most prevalent form of dementia in elderly people. It is a combination of more than one type of dementia. In majority of cases, mixed dementia is characterized by the presence of Alzheimer’s disease, vascular dementia, and/or Lewy body dementia.
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Alzheimer's Disease as a Risk Factor for Mixed Dementia
Since mixed dementia involves many pathological conditions, risk factors related to each of it can trigger the onset and progression of mixed dementia. One of the most salient ones is Alzheimer’s disease, and factors that play crucial roles in the disease development are age, family history, and heredity.
The risk of disease increases gradually over time and doubles every five years. Age-related brain atrophy, which occurs due to loss of neurons and neuronal connections in the brain, is an important causative factor for Alzheimer’s. Thus, age is the strongest risk factor.
The second most vital risk factor is family history. Although it is not an absolute determining factor, several studies have shown that people who have a parent or sibling with Alzheimer’s disease are more likely to get the illness. Likewise, the risk of disease development increases if more than one family member has it.
Both genetics and environmental factors play an important role in this context. Regarding heredity/genetics of this disease, the most prominent risk gene is APOE-e4, which is an allelic variant of APOE gene. However, inheriting APOE-e4 gene does not necessarily mean that the person will develop Alzheimer’s; risk genes only increase the chance of getting a disease.
Other Risk Factors for Mixed Dementia
Major risk factors for vascular dementia include age, history of heart attack and/or stroke, atherosclerosis, high cholesterol, high blood pressure, diabetes, smoking, obesity, and atrial fibrillation.
For Lewy body dementia, the major risk factor is an increasing age. A recent study involving Lewy body dementia patients has stated that risk factors related to Alzheimer’s disease and Parkinson’s disease increase the likelihood of developing Lewy body dementia. Such factors are presence of allelic variant of APOE gene, history of depression and anxiety, history of stroke, as well as family history of Parkinson’s disease.
Preventive Measures
Although increasing age is the strongest risk factor for dementia in general, steps that can be taken to prevent or atleast control the risk of disease development are as follows:
Physical activity – regular physical activity improves cardiac functions and blood circulation and helps to reduce body weight.
Healthy diet – healthy diet improves metabolic and cardiovascular functions of the body; thus, it reduces the chance of heart attack, stroke, and diabetes.
Quit smoking – smoking not only triggers the onset of dementia but also increases the chance of developing cardiovascular, metabolic, and pulmonary disorders.
Reduce alcohol intake – like smoking, excessive alcohol consumption also hampers overall physical and mental health.
Keeping an active mind – studies have found that carriers of APOE-e4 gene who were intellectually active during the middle age years are less likely to get Alzheimer’s disease in comparison to APOE-e4 carriers who were not engaged with mental activities in the middle age.
Staying socially active – studies have found that being lonely increases the likelihood of developing Alzheimer’s disease; therefore, frequent participation in social activities not only prevents cognitive decline, but also delays the onset of dementia.
Adequate sleep – getting quality sleep for sufficient duration reduces the risk of developing Lewy body dementia.
Reduce stress – stress-induced release of hormone cortisol is known to hamper memory formation; in addition, chronic stress often results in depression, anxiety, and dementia.
Treatment Strategies
Although there is no particular cure for mixed dementia, health professionals often consider treating the single type of dementia which is diagnosed as a coexisting factor in mixed dementia. Since no medicine is available thus far to completely cure dementia, treatment strategies are primarily designed to reduce the intensity of symptoms.
In case of Alzheimer’s disease, two types of FDA-approved drugs - cholinesterase inhibitors and NMDA receptor blocker (memantine) - are available to treat memory loss, confusion, and other cognitive impairments.
In case of vascular dementia, physicians generally prescribe medicines that reduce blood pressure and cholesterol level, control blood glucose level, and prevent blood clotting.
Finally, to treat Lewy body dementia patients, physicians generally rely on drugs that are used to treat Alzheimer’s disease, Parkinson disease, sleep disorders, and movement problems. In addition, physiotherapy, cardiovascular training, and balancing exercises are also helpful in reducing the burden of symptoms.
Further Reading
Understanding the role of sleep in dementia and associated illnesses