Transcript Global Prevalence of AD

Epidemiology of
Alzheimer’s Disease
Carla Falkenstein, MS
Course Content
• Description of the disease
process.
• Possible etiology based on
population studies.
• Global prevalence.
What is Alzheimer’s Disease?
• Neurodegenerative disease.
• Most common form of
dementia.
• Causes impaired cognitive
functioning.
• No known cure.
Diagnosis of AD
Because it is a progressive
disease with one of the
earliest symptoms being
memory loss, diagnosis is
difficult.
Common Symptoms
• Forgetting names and objects.
• Not recognizing family & friends.
• Forgetting one’s own phone
number or address.
• Difficulty finding a familiar place.
• Noticeable language &
intellectual decline.
Common Symptoms (cont’d)
• Forgetting to eat or maintain
one’s hygiene.
• Poor judgment, inability to follow
simple instructions.
• Progressive sense of distrust.
• Unusual agitation and irritability.
Age is a Primary Risk Factor
50
45
40
35
30
25
20
15
10
5
0
Prevalence of
AD(%)
65 -74
75-84
85+
Ages Prevalence
65-74 = 3%
75-84 = 18.7%
85+ = 47%
Stages of AD
SEVERE
1-3 Years
MODERATE
2-10 Years
MILD
2-4 Years
Disease Process
Disease Process (cont’d)
• 1st destroys neurons in parts of
the brain that control memory.
• Later attacks cerebral cortex areas responsible for language
and reasoning.
• Eventually nearly the entire brain
is atrophied.
Cause of Nerve Cell Death
Amyloid Plaques?
Neurofibrillary Tangles?
Amyloid Plaques
•Insoluble deposits of betaamyloid
•Plaques found in the spaces
between the brain’s nerve cells
•Plaques may be a cause or a
by-product of AD
Neurofibrillary Tangles
•Twisted threads of a protein
called tau.
•Tau is a protein found inside
nerve cells.
•In AD, Tau changes so that it
becomes 2 threads wound around
each other.
Other Genetic Factors
APOE є4 allele of the APOE
gene is a major risk factor for
late-onset AD.
However, much work is being
done to sort out all the potential
genetic factors involved in AD.
AD and Other Disorders
AD has similarities with other
neurodegenerative diseases:
•Prion, Parkinson’s and
Huntington’s diseases all cause
dementia.
•All involve deposits of abnormal
proteins in the brain.
Early Diagnosis
The earlier a correct diagnosis
can be made, the greater the
gain in managing symptoms
through pharmaceuticals.
•MRI
•PET
•SPECT
Causal vs. Associative Agents
•Advanced age
•Female gender
•Head Injury
•Cerebrovascular disease
•Low education levels
•Rural Residence
•Blood cholesterol
•Low blood levels of folic acid
•Inflammation
A Chain of Events Leads to
Disability and Death
GENES
LIFESTYLE &
ENVIRONMENT
BRAIN
DEVELOPMENT
& RESERVE
ALZHEIMER’S
SEVERITY IN BRAIN
NEURODEGENERATION
OTHER
DISEASES
AGE AT ONSET
OF SYMPTOMS
SEVERITY OF
SYMPTOMS
Global Prevalence of AD
United States
•Most common cause of AD
•Current cases: ~4 million
•Prevalence doubles every 5
years beyond age 65
•Nearly 50% of those aged 85+
have AD
Global Prevalence of AD
•African Americans in
Indianapolis are twice as likely as
Africans in Ibadan, Nigeria to
develop dementia & AD.
•Higher rates of AD in Japanese
men who emigrated to US
compared with those who
remained in Japan.
Global Prevalence of AD
Europe
There are currently an estimated
5.5 million people with dementia
in Europe.
Global Prevalence of AD
Developing Countries
Currently, ~18 million people in
the world have dementia.
66% of people with dementia
live in developing countries.
Current Research
•Continued search for causative
agents and etiology.
•Disease prevalence worldwide
with close attention to cultural
variations.
•Animal and population studies
that confirm causation and lead to
preventive or curative measures.