Prevalence and Causes of Alzheimer's Disease
Rudolph C. Hatfield, PhD., edited by Kathryn Patricelli, MAAccording to the DSM-5 the prevalence of neurocognitive disorders (dementias) is strongly associated with aging. In industrialized nations the diagnosis of dementia ranges from between 5% - 10% in individuals in their 70s. This risk increases significantly as people age with most sources reporting a sharp increase for every decade after the age of 65.
According to census data in the United States, of everyone in the US:
- About 7% with the diagnosis of Alzheimer's disease are between the ages of 65 - 74 years old.
- About 53% are between the ages of 75 - 84 years old.
- About 40% are over the age of 85.
- Less than 1% are younger than 65.
Although there is a slight decrease in the percentage of people over the age of 85 with Alzheimer's disease compared to those who are between the ages of 75 - 84, this may be a bit confusing. This happens because many people with Alzheimer's disease die well before they reach the age of 85. If more people lived longer with Alzheimer's disease who were in their early 80s, then the percentage of individuals over the age of 85 with Alzheimer's disease would be much higher. The vast majority of people who develop Alzheimer's disease between the ages of 65- 80 do not live to be 85 years old.
The DSM-5 suggests that the percentage of dementia that is attributable to Alzheimer's disease ranges from between 60% to 90% depending on the setting that the disease is diagnosed in and the criteria used to diagnose dementia. The organization, Alzheimer's Disease International, suggests that overall Alzheimer's disease accounts for 70%-75% of all dementia cases. However, when the brains of people who are diagnosed with dementia are analyzed after they have died, the findings indicate that they often have many different potential causes to their dementia. There are probably many factors that contribute to the development of dementia in most people.
Risk Factors
When one reads about the "causes" of Alzheimer's disease one should understand that the use of the word cause is not appropriate given the current understanding of how dementia happens and develops. There are no guaranteed identified causes of Alzheimer's disease in any single person. Instead, competent researchers and clinicians refer to certain types of risk factors that can increase the chances that one may develop Alzheimer's disease.
A risk factor is some type of condition or experience that can increase the chance that a person might develop a certain disease or disorder. However, it does not guarantee that they will develop the disease or disorder. When people read about the causes of Alzheimer's disease, what they are reading about are certain risk factors that can increase the chances of developing the disorder. Risk factors are additive, meaning that if you have more than one risk factor the chances of developing the disorder or disease increases compared to having only one risk factor. The more risk factors a person has the greater the chances are that they will develop the disease or disorder, but there is no guarantee that this will happen.
As one can see by the above description of the data from the U.S. Census, the major risk factor for the development of Alzheimer's disease is increasing age. The chances that a person will be diagnosed with Alzheimer's disease increase dramatically as a person reaches the age of 65 and over. However, simply getting older does not cause a person to develop Alzheimer's disease. In fact, the majority of people that do get older do not develop Alzheimer's disease. For instance, the DSM-5 reports that the prevalence of dementia overall is about 5%-10% of people who are in their 70s and only about 25% of all people who are older than 70. Thus, aging alone is not a cause of Alzheimer's disease. However, getting older increases the risk that someone might develop the disorder.
Researchers report that the development of any form of dementia is due to the interaction of many factors. Thus, as a person gets older there must be other factors that interact with the aging process that result in an increase in the chance to develop Alzheimer's disease or other forms of dementia. In the second part of this article several of these additional risk factors will be discussed.
Resources
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Articles
- Introduction & Causes of Cognitive Disorders
- Dementia
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Alzheimer's Disease
- Alzheimer's Disease
- Prevalence and Causes of Alzheimer's Disease
- Causes of Alzheimer's Disease Continued
- Risk Factors for Alzheimer's Disease
- Symptoms of Alzheimer's Disease
- Warning Signs of Alzheimer's Disease
- Diagnosis of Alzheimer's Disease
- Diagnosis of Alzheimer's Disease - Imaging Procedures and Psychological Evaluation
- Diagnosis of Alzheimer's Disease - Neuropsychological Testing
- Treatment of Cognitive and Behavioral Symptoms associated with Alzheimer's Disease
- Research and Prognosis on Alzheimer's Disease
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Other Cognitive Disorders
- Vascular Neurocognitive Disorder
- Vascular Neurocognitive Disorder Continued
- Lewy Body Dementia
- Symptoms of Lewy Body Dementia
- Diagnosis and Treatment of Lewy Body Dementia
- Reversible Cognitive Disorder - Dementia Syndrome of Depression
- Neurocognitive Disorder Due to Another Medical Condition
- Reversible Cognitive Disorder - Delirium
- Prevention of Dementia and Other Cognitive Disorders
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Dementia Coping Skills & Behavior Management
- Coping Skills for Those With Dementia
- Coping Skills for Dementia Caregivers
- Services for Dementia Caregivers
- Communication Tips for Dementia Caregivers
- Behavioral Management for Dementia Caregivers
- Behavioral Management for Dementia Caregivers Continued
- Tips for Dealing with Specific Dementia Problematic Behaviors
- Tips for Dealing with Specific Dementia Problematic Behaviors Continued
- Traumatic Brain Injury (TBI)
- Conclusion and Resources
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News
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Questions and Answers
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Book & Media Reviews
- Alive with Alzheimer's
- Alzheimer's
- Days With My Father
- Decision Making, Personhood and Dementia
- Dementia
- Dementia Caregivers Share Their Stories
- Hearing the Person With Dementia
- How We Think About Dementia
- Inside Assisted Living
- Mild Cognitive Impairment and Early Alzheimer's Disease
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16 more
- Mom's OK, She Just Forgets
- My Book about Brains, Change and Dementia
- Nothing about us, without us!
- Remembering Home
- Rights, Risk and Restraint-Free Care of Older People
- Speaking Our Minds: Revised Edition
- Still Alice
- Telling Tales About Dementia
- The Almost Moon
- The Emotional Journey of the Alzheimer's Family
- The Enduring Self in People with Alzheimer's
- The Story of My Father
- Voices Of Alzheimer's
- When It Gets Dark
- When Someone You Know Is Living in a Dementia Care Community
- Wrinkles
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Links
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Videos
- Overview of Dementia with Lewy Bodies
- Common Challenges: Driving
- Diagnosis and Management of Vascular Dementia
- Difference Between Alzheimer's and Dementia
- Why Early Detection of Alzheimer’s Disease Matters
- Looking Beyond Alzheimer’s Disease: An Overview of Other Major Forms of Neurodegenerative Disease
- New Definition of Alzheimer’s Changes How Disease Is Researched
- Lewy Body Dementia: Most Common Disorder You’ve Never Heard Of
- Living With Traumatic Brain Injury
- Early Detection of Alzheimer's Disease
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37 more
- Seeing Alzheimer's in a New Way
- Inside Alzheimer’s disease
- Alzheimer's Screening
- Neurology: Testing for Alzheimer's
- Alzheimer's and Dementia Caregiver Training: Sexually Inappropriate Behaviors
- Alzheimer's and Dementia Caregiver Training: Depression/Apathy
- Alzheimer's and Dementia Caregiver Training: Agitation and Anxiety
- Alzheimer's and Dementia Caregiver Training: Aggressive Language/Behavior
- Alzheimer's and Dementia Caregiver Training: Sleep Disturbances
- Alzheimer's and Dementia Caregiver Training: Repetitive Phone Calls
- Alzheimer's and Dementia Caregiver Training: Home Safety
- Best Practices & Emerging Therapies for Patients with Alzheimer’s Disease
- Recognizing the Early Signs of Dementia
- Effective Treatments and Prevention of Alzheimer’s Disease: The Time is Now - Research on Aging
- Dementia – it affects us all
- Falls Prevention in People with Dementia
- Caregiver Training Part I: Introduction
- Caregiver Training Part II: Hallucinations
- Caregiver Training Part III: Refusal to Bathe
- Caregiver Training Part IV: Refusal to Take Medication
- Caregiver Training Part V: Repetitive Behaviors
- Caregiver Training Part VI: Repetitive Questions
- Caregiver Training Part VII: Sundowning
- Caregiver Training Part VIII: Wandering
- The Benefits of Early Detection of Alzheimer's Disease
- A New Way To Look At Alzheimer's
- The Healing Power of Music
- Falls Prevention in People with Dementia
- Falls Prevention in People with Dementia
- Protecting & Caring for Patients with Dementia
- Dementia 101 in 101 Seconds
- Normal and Abnormal Aging and the Brain
- Alzheimer’s Disease and Parkinson’s Disease
- Aggressive Behavior in People with Dementia
- Diagnosing Alzheimer’s
- Signs of Alzheimer’s
- Practical Tips for Travelling with a Loved One with Alzheimer's Disease
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