Download Well-Documented Modifiable Stroke Risk Factors

Stroke Epidemiology-2001
Aurora K. Pajeau, M.D., MPH
Stroke Director
LSUHSC-Shreveport
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
1
Stroke-2001
• 3rd leading cause of death in the United States
• A major cause of disability among adults.
• Estimated 750,000 annual incident strokes.
• >4 million stroke survivors.
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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Well-Documented Modifiable
Stroke Risk Factors
Factor
Prevalence
HTN (Age 50-80) 20-55%
Smoking
PAR%
40-20
RR %Risk /c Tx
4.0-1.4
38%
25%
12-18
1.8
50% /c 1yr
DM
20%
Asxto Carotid Stn 2-8%
14-58
2-7
1.8-6
2.0
/c BP 
50%
TC men 55y
women 65y
A Fib
1.8/ 240-279 20-30%
2.6/>280
/c statins
1.5-23
5 2.6-4.5
68% A/C
21%ASA
Adapted from Goldstein et al: Stroke 2001;32:280-299
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2001
25%
40%
0.5-8.8%
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Congress of Epidemiology
2001Toronto, Canada
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Hyperlipidemia
~36% (60x106) adults in U.S.
Mean TC levels increase in men till age 5564 then decline.
25% of American men and 28% of women
have TC levels >240mg/dl (6.21mm/l)
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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Normal Endothelium
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Congress of Epidemiology
2001Toronto, Canada
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Fibrous Plaque
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Congress of Epidemiology
2001Toronto, Canada
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Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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Stimuli Initiating
Atherosclerosis
Hypertension
Mechanical forces, sheer stress
response
Oxidized LDL
Adhesion, permeability,
deposition
Homocysteine
Cigarettes
Hyperglycemia
[O] LDL, vascular toxin
Toxic, oxidizing glycation
products
Arterial retention of Trigl
Infection
Vessel wall injury
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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Novel Risk Factors
• Hyperhomocysteinemia
• Infection and inflammation
• Additional genetic factors
– Hemostatic and coagulation disorders
• Leisure time inactivity and obesity
• Fast food restaurant abuse
• Second hand smoke
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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Hyperhomocysteinemia
• HC is a highly reactive amino acid toxic to
vascular endothelium
– Pro-atherogenic and pro-thrombotic effect on
blood vessels
• HC can potentiate the auto-oxidation of
LDL
• HC is emerging as a potentially modifiable
risk factor for atherosclerosis
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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Infection and Inflammation
• Infectious agents contribute to initiation
and chronic formation, progression and
activation of atherosclerotic plaques.
• Infectious agents can be seen as triggers
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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Infection and Inflammation


•
•


Chlamydia pneumoniae
Helicobacter pylori
Cytomegalovirus
Herpes virus
Periodontal disease
Genetic influence
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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Chlamydia Pneumoniae
• Obligate intracellular parasite Infects
mononuclear phagocytes
• Macrophages derived from them localize
in atherosclerotic plaque to provide
mechanism for entry of organism into
vessel wall
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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Helicobacter pylori
• Thought to be a potential factor in causing
pathophysiology of atherosclerosis
• One strain was found to be associated
with increased cytokine expression.
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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Periodontal Disease
• A mechanism for chronic systemic
inflammation from Gm (-) organisms
• Advanced disease estimated prevalence:
– 15% -60-64 yo
– >45% in >65 y.o.
• One study showed a significant ischemic
stroke risk (RR 2.1) among those with
periodontitis.
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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Genetic Inflammatory Disorders
• Genetic mutations & gene polymorphisms
– Associated with inflammatory pathways
– May lead to increased susceptibility to
develop atherosclerosis
– Particular HLA types
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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Genetic Inflammatory Disorders
• Continuing research in linkage analysis
studies and association studies with
genetic influence based on risk factor
exposure are needed.
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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Genetic Hemostatic &
Coagulation Factors
•
•
•
•
•
•
Sickle cell disease
CADASIL
Coagulation disorders
Connective tissue disorders
Vasculopathies
Metabolic disorders
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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CADASIL
• Cerebral autosomal dominant arteriopathy
with subcortical infarcts and
leukoencephalopahty
– monogenic inherited small vessel disease
– Notch 3 gene on chromosome 19q12
– Migraines, TIAs, lacunar strokes
– Stroke and dementia in early middle age
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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Fast Food Restaurant Abuse
• Increased trans fatty acid intake from
foods fried in partially hydrogenated fats
at fast food restaurants
– Trans unsaturated fatty acids LDL and HDL
– Major contributor is hydrogenated fats
• Builds plaque in arteries
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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Leisure Time Inactivity
and Obesity
• Obesity defined as BMI>30kg/m2
–  with age
– Associated with  BP,
–  glucose, lipids*
*Walker et al: Am J Epi 1996
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2001
Congress of Epidemiology
2001Toronto, Canada
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Guidelines for Stroke Prevention
•
•
•
•
•
•
Antiplatelets & anticoagulation
HTN control
Statin agents
RAAS inhibition
Leisure time activity
Dietary guidelines
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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Guidelines for Stroke Prevention
 Aspirin and Sub Q heparin for inpatient
with acute stroke
 IV heparin for TIA from symptomatic
carotid stenosis, until CEA
 Bottom line: ASA/ext. release
dipyridamole better than aspirin alone,
may be better than clopidogrel
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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Use of Anticoagulant Therapy
• Coagulopathies (INR 2-3), prosthetic heart
valves( INR 2.5-3.5)
• Nonvalvular atrial fibrillation (INR 2-3)
– Age <65, no risk factors
– Age <65, /c risk factors
– Age 65-75, no risk factors
– Age 65-75 /c risk factors
– Age >75, /c or /s
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2001
Aspirin
Warfarin
Aspirin or Warfarin
Warfarin
Warfarin
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2001Toronto, Canada
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Hypertension Control
• SBP<140mmHg & DBP<90mmHG
• <135/<85 if target organ damage
• Antihypertensive medications
• Lifestyle modification
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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Leisure Time Inactivity
and Obesity
• Walking AM &PM 1.8 mi/d most days of
week will modify risk of cardiovascular
disease and stroke**.
*Walker et al: Am J Epi 1996; **Rexrode et al:JAMA
1997.**Abbott RD et al: Am J Epi 1994
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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Leisure Time Activity
Leisure Time Activity
• Exercise will  insulin resistance,
fibrinogen, LDL and weight and will 
HDL
– There is no dose relationship with level of
activity
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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Novel Approaches
to Stroke Prevention
• Statin agents used for hyperlipidemia may reduce
risk of stroke*.
• Antihypertensive agents that inhibit the reninangiotensin –aldosterone system (RAAS) may
reduce risk by non-hypertensive lowering
mechanisms**.
*Plehn et al: Circ 1999; LIPID Study Gp: N Engl J Med 1998
**Van Bortel et al: Am J Card 1995; Thybo et al: HTN 1995
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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Stroke Prevention Therapy
• AHA Dietary Guidelines, 2000*
– General population
– Special populations
– Ancillary lifestyle issues
• BMI
120% of ideal body weight for height
Krauss et al, Stroke 2000.
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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Physician-Community
Knowledge Gap
• Well-defined stroke prevention measures
underutilized, misapplied
• Knowledge of risk factors for primary
stroke prevention
– CME, physician recertification
– Promote stroke prevention legislation
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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U.S. Legislative Measures
• Public education and awareness of stroke
• Improved stroke care
• Kennedy Bill
– Establish a national clearinghouse on stroke
treatment & research
– Authorize a national public awareness and education
plan
– Provide state grants to ensure stroke patients have
access to high quality care
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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STOP Stroke Act
• Stroke Treatment and Ongoing Prevention
• Public awareness campaign
• Grant program
• Ensure training in prevention & treatment for
medical personnel
• Create comprehensive research for best
practices, barriers, disparities; measure effect
of public awareness efforts.
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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STOP Stroke Act
Stroke legislation hot line:
www.stroke.org/strokesmart.cfm
Thursday, June 14,
2001
Congress of Epidemiology
2001Toronto, Canada
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