Alzheimer's Disease

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Jeremiah Owings

Dr. Mary Hayes

Biological Science 102

21 April, 2017

Alzheimer’s Disease

What is Alzheimer’s? According to the Merriam-Webster’s dictionary, “Alzheimer’s Disease is a degenerative brain disease of unknown cause that is the most common form of dementia. It usually starts in late middle age or in old age and results in progressive memory loss, disorientation and changes in personality and mood. It is marked histologically by the degeneration of brain neurons especially in the cerebral cortex and by the presence of neurofibrillary tangles and plaques containing beta-amyloid. Simply put, it is a disease of the brain that causes people to slowly lose their memory and mental abilities as they grow old. It is the most common cause of dementia and it affects more than 15 million individuals worldwide.”

 The disease gained its name from a German neurologist named Alois Alzheimer. He was noted for his work in the pathology of the nervous system. The majority of his medical contributions centered on neurohistology. The disease was later named in his honor by the German psychiatrist Emil Kraepelin.

One thing we must understand about Alzheimer’s Disease is that there is not a singular test to be done to diagnose it. While physicians can almost always determine if a person has dementia, it may be difficult to determine the exact cause. Diagnosing Alzheimer's requires careful medical evaluation. There are a few different combined ways to diagnose Alzheimer’s in a patient. First thing is by evaluating the patient’s extensive medical history. Mental status and mood testing along with a physical and neurological exam can be used to diagnose as well. The other way to diagnose a patient that is used is by running different tests. This can include blood tests and brain imaging to rule out other causes of dementia-like symptoms.

The statistics concerning those that are affected are really astonishing. With the number of people that are diagnosed, it is most certain that we all know at least one person that suffers from it whether we realize it or not. It would be safe to say that we know more than one person affected by it. “1 in 10 Americans that are sixty-five and older are diagnosed with it. Out of those that are affected, about two-thirds of these are solely women.” While Alzheimer’s does not discriminate against sex, age, race or religion, African Americans are twice as likely to develop this disease than older white people. Behind African Americans, we have Hispanics that are about one and a half times more likely to develop it than older white people. Because of the increasing number of people age 65 and older in the United States, particularly the oldest-old, the number of new cases of Alzheimer's and other dementias is projected to soar. At present time, someone in the United States develops Alzheimer's dementia every 66 seconds. It is projected by the middle of this century, someone in the United States will develop it every 33 seconds.

The mortality rate of those that have Alzheimer’s Disease really is not different of a healthy person. While men that are considered otherwise healthy are expected to live until about 76 years old, women are expected to live to be about 81 years old. Among people age 70, 61 percent of those with Alzheimer's are expected to die before the age of 80 compared with  percent of people without Alzheimer's — a rate twice as high. It is the only top ten cause of death that is not curable, preventable, nor can it be slowed down. As Americans get older and continue to age, it is becoming more of a leading cause of death than ever. While it is the sixth leading cause of death among all Americans, it is the fifth leading cause of death among the elderly (those that are 65 years of age and older) and it is the leading cause of disability and poor health in them as well. “Although deaths from other major causes have decreased significantly, official records indicate that deaths from Alzheimer's disease have increased significantly. Between 2000 and 2014, deaths from Alzheimer's disease as recorded on death certificates increased 89 percent, while deaths from the number one cause of death (heart disease) decreased 14 percent”.

The greatest risk factor for Alzheimer’s is most certainly increasing age. As previously stated, most of those that affected are 65 years old or older. “One in nine people are in this age group and nearly one-third of people age 85 and older have Alzheimer’s.” It was believed in the 1960’s and 1970’s that aluminum was a possible contributor of Alzheimer’s, very few experts now believe that this is so. An obvious factor of developing this disease, as with many other, is family history. Whether it be from environmental causes or genetics. There are two categories of genes that influence whether or not someone develops it: risk genes and deterministic genes. Alzheimer’s genes have been found in both categories. Risk genes just increase the likelihood of developing a disease, while deterministic genes are a direct cause of developing diseases. There are multiple risk genes that have been found to increase the risk of Alzheimer’s. They are apolipoprotein E-e4, or APOE-e4, which is the first risk gene identified and remains the one with strongest impact. Other common forms of the APOE gene are APOE-e2 and APOE-e3. As far as the deterministic genes go, “scientists have discovered variations that directly cause Alzheimer’s disease in the genes coding three proteins: amyloid precursor protein (APP), presenilin-1 (PS-1) and presenilin-2 (PS-2). When Alzheimer’s disease is caused by these deterministic variations, it is called “autosomal dominant Alzheimer’s disease (ADAD)” or “familial Alzheimer’s disease,” and many family members in multiple generations are affected. Individuals with these genes usually develop symptoms in their 40s or 50s. Deterministic Alzheimer's variations have been found in only a few hundred extended families worldwide. True familial Alzheimer’s accounts for 1 percent of cases.” Three factors that may be able to be influenced that lead to Alzheimer’s are head injuries, heart-head connections and all together healthy aging.