march,03,20051 alzheimer disease can we prevent it? kamal kallab md arab conference on alzheimer...

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ALZHEIMER DISEASECan we prevent it?

Kamal KALLAB MDArab Conference on Alzheimer DiseaseMarch 2-4, 2005

Beirut

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ALZHEIMER DISEASE Can we prevent it?

Two main reasons: Alzheimer Disease (AD) Is a public

health problem worldwide AD is a source of fear especially in

individuals who have a family history

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Two main difficulties: Follow-up length Multiple variants to adjust

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Introductory remarks: Prevention from AD must be a part of

a comprehensive concept of Dementia (Frequency of mixed dementia)

Prevention from AD must be a part of a comprehensive strategy of management of AD

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Comprehensive concept of Dementia: Similarities with a treasure or a bank account

Built up period ( learning) Stabilization Progressive loss

Use Regular devaluation (Normal aging?) Rapid devaluation ( Degenerative?) Bad management ( non healthy life?)

More acute phenomena: Bankrupt, Stock market crash ( Stroke, trauma,

infections,..)

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In case of AD, the mental status at a given time, is the result of AD lesions and possible other pathologic processes. Some are preventable or treatable

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Normal aging

AD

Trauma

Stroke

infection

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Theses pathologic processes are: Stroke: Second cause of dementia Infections Trauma Toxic substances and drugs Metabolic disorders Other associated degenerative

diseases

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Comprehensive strategy in the management of AD

Prevention

Slowing (or stopping) disease course

Substitution of chemical deficit / Inhibition of excitotoxicity

Relieve other symptoms

Better use of remaining skills

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ALZHEIMER DISEASE Can we prevent it? Prevention Slowing ( or stopping) disease course

Vaccination Secretase inhibition? Anti-NMDA? GinkoBiloba? Idebenone Neurotrophic factors,..

Substitution of chemical deficit / Inhibition of excitotoxicity Cholinesterase inhib. Anti-NMDA

Relieve other symptoms : Non pharmacological measures antidepressants, antipsychotics, anxiolytics, ..

Better use of remaining skills : Environnement (emotional, psychological, familial, institutional,…) Other medical problems Speech therapy, occupationnal therapy,..

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Prevention from AD: State of the art In contrast with the disease prevalence,

few amount of valid data Randomized studies can be easily

biaised Reliability of questionnaire in case of

memory disturbances Multiple factors- statistical analysis pitfalls

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Numerous possible preventive factors were studied.

Except for Hormone Replacement Therapy (HRT), No large scale randomized primary prevention trials completed

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HRT: Kawas, Neurology 1997: 472 peri or post-

menopausal women, 16 years. Relative risk 0.46 Tang, Lancet 1996: meopausal 156 ORT/1124 RR 0.4 Shumaker, JAMA 2003 (WHI study): 4532

postmenopausal women, > 65, HRT group 2229, conjugated equine estrogen+medroxyprogesterone. 40 of HRT group developped AD versus 21 in control group RR 2.05

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HRT: Conclusions Lesson of Humility Symptomatic action on cognition? What about different types of drugs? Role of early medication onset age?

(Henderson, Neurol Neurosurg Psychiatry. 2005)

Risk-benefit: HRT is no more recommended for AD prevention, unless future data….

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Non Steroidal Antiinflammatory Drugs (NSAIDs) Epidemiologic studies:

Broe, Arch. Neurol, 2000 - / Beard, Mayo clinic process, 1998 +/ Rotterdam study, 1998+?/ Stewart, neurology, 1997+,..

In’t Veld & all,NSAID on risk of AD, N Engl J Med, 2001

Metaanalysis Ongoing: http://www.2stopAD.org ( Randomized

control trial)

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NSAIDs In’t Veld & all,NSAID on risk of AD, N Engl J Med,

2001 6989, >55, Average FU 6.8 years computerized pharmacy records 394 dementia, 293 AD RR according to duration:

< 1month: 0.95 1-24 m: 0.83 > 24 months cumulative use: 0.20

Critical period during wich NSAID use is protective?

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NSAIDs Metaanalysis: Etminan BMJ 2003: 9 all

NSAID >55, ( 6 cohort 13211 pts, 3 case control 1443 pts)

Pooled RR: 0.72 According to duration:

Short 0.95 Intermediate 0.83 Long-term 0.27

Pooled RR among Aspirin users 0.87 ( 0.7-1.07)

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NSAIDs: Effect on cognitive function: Hee Kang, Neurology

2003: 13255 women, tests administered by telephone RR0.75

aspirin +15y, RR 0.79 NSAID ( mainly Ibuprofen) +8 y. For global cognitive decline, nonaspirine agents shoed lower RR ( 0.93 vs 0.77)

Protection from Parkinson disease: Chen, Arch Neurol 2003:

44057 men, 98845 women Nonaspirin NSAID: Pooled RR regular users vs non

regular users 0.55 Aspirin: Non significant difference

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NSAIDs Mechanism of action:

Cultured cells: Ibuprofen, Indomethacin and Sulindac lowered the production of the highly amyloidogenic Abeta42 peptide by as much as 80%

Mouse models: Similar effects with Ibuprofen on Abeta42

Alteration of gamma secretase activity This effect was not seen with all NSAIDs Independent of cyclooxygenase inhibition Protective NSAID mark: inhibit GTP-binding protein

Rho?

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NSAIDs conclusions: Low dose nonaspirin NSAID, especially

Ibuprofen 200 mg/d, have to be considered as possible preventive tool from AD.

Benefit Risk golden rule High Risk group ( strong family history ) ?

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Statins: Epidemiologic Studies:

Wolozin, Arch Neurol, 2000: Prevalence of AD in the groupe taking statins (lovastatin

or pravastatin) was 60 to 70% (p<0.001) lower than the total patient population and patients taking other medications typically used in the treatment of Hypertension or cardiovascular disease.

Jick, Lancet 2000: 284 AD, 1080 Control RR ror statin users 0.2 VS 1 for non treated or treated with

non statins Zandi, Arch Gen Psychiatry. 2005:

“we found no association between statin use and subsequent onset of dementia or AD. Further research is warranted before costly dementia prevention trials with statins are undertaken”.

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Statins: Mechanisms of action:

Direct association between amyloid processing and cholesterol in the brain: Combined in vitro and guinea pig study found that simvastatin and lovastatin reduced intra and extracellular levels of amyloid peptides Abeta40 and 42

Decreasing the risk of stroke

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Antihypertensive therapy Epidemiological studies:

Rigaud, J Hum Hypertens, 2000 Birkenhager, Arch Intern Med, 2001 Forette, Arch Intern Med, 2002: (syst-euro

study) >60 y, SBP 160 to 219, non dementia at

randomization nitrendipine elanapril hydrochlorothiazide reduction of risk of dementia 55% including AD

Tzourio, Arch Intern Med, 2003

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Antihypertensive therapy Conflicting data

Length of follow-up Type of antihypertensive therapy used Frequent association of AD and Vascular dementia

In a comprehensive management of Dementia, HT should be treated actively

If further data will suggest clear advantage of one drug over other, then it will at least be a reason to choose it for HT treatment.

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Antioxidants: Theoretical Background

AD lesions = Free radical exposure associated lesions ( Bell 1997, Christen 2000)

Exogenous antioxydants reduce the toxicity of beta-amyloid in in-vitro studies of patients with AD ( Bell 1997, Christen 2000)

AD brain contains elevated levels of endogenous antioxydants (Morris 1998)

Controlled trial of selegiline and/or alphatocopherol suggested an efficacy in slowing disease progress ( Sano, N Engl J Med, 1977)

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Antioxidants: Epidemiological studies:

Several observational studies Two large prospective cohort studies

Engelhart JAMA 2002 Morris JAMA 2002

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Antioxidants: Engelhart JAMA 2002:

5395 pts, >55, 6 y FU, 197 developped dementia, of whom 146 AD, Vitamine E intake from food

adustements for multiple variables made: Age, sexe, baseline MMS, alcohol intake, education, smoking, BMI, carotid plaque and antioxydant supplements

High intake ( >15.5mg/d) group was found 43% less likely to develop AD than low intake (<10.5mg/d)

This effect was more pronounced for smokers Vitamine C intake has a positive effect

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Antioxidants: Morris JAMA 2002

815 men, =/>65, 3.9 y FU, Vit E intake from food

Adjustement for age, education, sexe, race, ApoEepsilon 4 and FU length

People with High intake (>10.4IU/d) were 70% less likely to be diagnosed with AD than the lowest intaket group ( <7.0IU/d)

ApoE epsilon 4 negative Pts showed significant protection

Antioxydant supplements ineffective

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Antioxidants: Limitation of these studies

Duration of FU Food frequency questionnaire with possible

cognitive dysfunction ( responses require sustained motivation, attention and memory)

Why only Antioxidants intake from food ( not supplements) affected outcomes??

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Antioxydants: Since the risk of vitamin E

supplementation is small it may be appropriate to consider 400-800 IU/d in case of strong family history

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Diet Consumption of fish and n-3 fatty acids:

Morris, Arch Neurol 2003: Obsevational study, 815 people, 65-94y.

high intake of fish(once or more weekly) had RR 0.4 compared to rarely or never ate fish (9.5% absolute reduction)

Methodological pitfalls: adjustement for ather variants

Panza, Public Health Nutr. 2004 Mediterranean diet and cognitive decline, literature review

“Essential components of the Mediterranean diet--MUFA, cereals and wine--seem to be protective against cognitive decline”

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Alcohol Light to moderate drinking may be

protective Alcoholism is associated with

cognitive dysfunction

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Physical Activity Brnes, J Am Geriatr Soc, 2003:

Observational study, 349 people, 55 or older, 6 y FU

Higher level of cardiorespiratory fitness at baseline were associated with better preservation of cognitive function

Verghese, N Engl J Med, 2003: Observational study, 469 subjects, =/>75y, 5.1y

FU No relationship between physical activity and risk

of dementia

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Cognitive activity Verghese, N Engl J Med, 2003:

Observational study, 469 subjects, =/>75y, 5.1y FU

Reading, playing board games and playing musical instruments, dancing were associated with reduced risk of dementia

Association with the cognitive-activity score persisted after exclusion of subjects with possible preclinical dementia at baseline

Results were similar for AD and Vascular demantia

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Cognitive activity: Critics

Given the same degree of AD pathology, people with better baseline cognitive reserve may still have enough skills to prevent the diagnosis of dementia

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CONCLUSION: Possible benefit:

NSAIDs low doses, long term exposure Statins Vitamine E Fish Cognitive activity Physical activity?

Lessons from HRT In the absence of definite approval, use of drugs

must take in consideration the risk of developping AD vs the risk of medication

Prevention of cognitive decline must include other causes of dementia

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march,03,20051 alzheimer disease can we prevent it? kamal kallab md arab conference on alzheimer...

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alzheimer disease ad

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disease prevalence

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management of ad prevention

case of ad

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