Risk Factors for CHD

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Risk Factors for CHD
Introduction to Cardiac Care Course10th
September 2008
Dr Neil Chapman International Centre for
Circulatory Health, Imperial College St Marys
Hospital
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Outline

• Epidemiology of CHD
• Overview of risk factors
• Ethnic differences in CHD risk factors
• Benefits of treating risk factors
• How do we do
• Conclusions

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Selected major global risk factors for death
disability

• Alcohol
• Childhood sexual abuse
• High BMI
• High BP
• High cholesterol
• Illicit drugs
• Indoor smoke
• Iron deficiency
• Lack of contraception
• Lead exposure

• Low fruit vegetable intake
• Occupational injury
• Physical inactivity
• Tobacco
• Underweight
• Unsafe injections
• Unsafe water, sanitation
• Unsafe sex
• Vitamin A deficiency
• Zinc deficiency

World Health Report 2002
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Global mortality due to leading risk factors
High blood pressure gt 115 mmHg systolic High
cholesterol gt 3.8 mmol/L
World Health Report 2002
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Cause of death, UK
Men
Women
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16
13
BHF Statistics Database, 2005
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Deaths in UK 2001
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Death rates from CHD, men and women aged 35-74,
1998, selected countries
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Changes in CHD death rates, men and women aged
35-74, 1989 - 1999, selected countries
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All cardiovascular deaths, UK 1970 - 2001 (men
women, lt75y)
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Why are CHD rates so high?Statistically proven
risk factors include

• Snoring
• Not having siesta
• Non - English mother tongue
• Slow beard growth
• No varsity athletics at college
• Poor church attendance

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Risk Factors for CHD

• Modifiable
• High LDL cholesterol
• High blood pressure
• Smoking
• Low HDL cholesterol
• Lack of exercise
• Diabetes and glucose intolerance
• Left ventricular hypertrophy
• Central obesity
• Homocysteine
• Clotting factors
• Oral contraceptives

Non-modifiable Age Sex Family
history Genetic Other Birth weight
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9 risk factors explain 90 of PAR of MI15152
cases AMI 14820 controls in 52 countries
Smoking ApoB/ApoA Hypertension Diabetes Abdominal
Obesity Psychosocial stress Fresh fruit
vegetables Alcohol Physical activity
Interheart, Lancet 2004
PAR population attributable risk
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Lifestyle factors protective against MI
Non-smoking Fresh fruit vegetables Alcohol Phys
ical activity
Interheart, Lancet 2004
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Cardiovascular Death
Why is the UK a World Title contender?

• Bad luck? X
• Genetics? X
• Unidentified factor? X
• High levels of known risk factors? ?
• Low levels of intervention? ?

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Secondary prevention in high risk (CHD)
patientsEUROASPIRE I II
Prevalence of risk factors ()
Obesity
Diabetes
Smokers
BP ? 140/90
TC ? 5mmol/l
Lancet 2001
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Association between major risk factors coronary
heart disease / cardiovascular disease
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Cholesterol is associated with CHD and stroke
Eastern Stroke Coronary Heart Disease Project
Asia Pacific Cohort Studies Collaboration
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Cholesterol CV risk some facts

• Total cholesterol gt 3.8 mmol/L accounts for an
  estimated
• 56 of ischaemic heart disease
• 18 of cerebrovascular disease
• Overall, estimated to account for
• 4.4 million deaths (7.9 of total)
• 40.4 million DALYs

World Health Report 2002
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Blood pressure is strongly associated with
cardiovascular disease
Stroke usual BP (in 5 categories defined by
baseline BP) 7 prospective observational studies
843 events
Coronary heart disease usual BP (in 5
categories defined by baseline BP) 9 prospective
observational studies 4856 events
McMahon Collins. Brit Med Bull 1994
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BP risk of stroke
BP risk of IHD
Asia Pacific Cohort Studies Collaboration J
Hypertens 2003
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BP cardiovascular risk - facts

• 10-12 / 5-6 mmHg higher usual BP associated
  with
• 25 higher risk of CHD
• 40 higher risk of stroke
• MacMahon et al. Lancet 1990
• SBP gt 115 mmHg accounts for an estimated
• 49 of ischaemic heart disease
• 62 of cerebrovascular disease
• World Health Report 2002

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Most MIs strokes occur in individuals with
normal or near normal levels of BP
World Health Report 2002
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HDL (high density lipoprotein) cholesterol CHD
T Chol (mmol/l)

CHD/1000 per year
HDL cholesterol (mmol/l)
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CHD mortality by smoking status
Annual death rate/ 100,000 men
Daily cigarette consumption
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Premature Deaths From Tobacco Use


Preventable if adults quit (halving global
cigarette consumption by 2020)
Preventable if young adults do not start (halving
global uptake by 2020)
Other premature deaths from tobacco-related causes
2000-2024
2025-2049
The World Health Report, 1999 Making a Difference
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but weve only just banned smoking in public
places
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Interaction of cardiovascular risk factors
DBP ? 95 mmHg
Pardell J Hypertens 2005
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Worldwide prevalence of diabetes 1997
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Projected prevalence of diabetes in 2025
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CV mortality in diabetics non-diabetics
3-fold increase in CHD mortality
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Non-diabetics
5
Diabetics
4
Relative Risk
3
2
1
0
CHF
CHD
Stroke
All CVD
All cause
Non-CVD
Other CVD
Asia-Pacific Cohort Studies Collaboration
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Risk factors in type 2 diabetic non-diabetic
populations
SBP
LDL
HDL
T Chol
Trigs
BMI (kg/m2)
Nathan DM, Lancet 1997
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Lifestyle coronary heart disease risk
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Obesity
6 year old Russian boy - 15 stone (95 kg)
May 26 2006
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Evening Standard
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BESITY

• Obesity levels in UK have tripled in the past 2
  decades
• A fifth of men and a quarter of women are now
  obese.
• Obesity is rising among children.
• Maturity-onset diabetes is emerging in childhood.
  
• Obesity reduces life expectancy by 9 years.

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The Danish advertising campaign promoting fresh
fruit vegetable consumption, 6-a-day .. and
exercise
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Salt intake, blood pressure hypertension
The InterSalt Study
Dahl 1960
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Exercise
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Physical fitness predicts CV mortality1960 men
followed for 16 years (baseline fitness by
bicycle ergometry)
Risk ratio for CV mortality, quartile 4 vs.
quartile 1 0.41, p0.013
Sandvik, NEJM 1993
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Hypertension and alcohol
30
25
20
15
hypertensive
10
5
0
Increasing alcohol intake
C. Lian, French army physician, 1915
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Hypertension and alcohol
30
25
20
15
hypertensive
10
5
0
Sobres lt1L wine/day
Grands buveurs
Moyens buveurs
Tres grands buveurs ?3L wine 4-6 aperitifs
C. Lian, French army physician, 1915
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Ethnic differences in CHD risk factors
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Standardised mortality ratio for CHD by sex
country of birth, 1989/92, England Wales
SMR
www.heartstats.org
Wild S, McKeigue P (1997)
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Relative risk of hypertension and diabetes by UK
ethnic group
Relative risk
Whitehall II Whitty et al 1999
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CVD risk factors (London men) by ethnicity
In one observational study in women, SBP 17
mmHg greater in blacks than whites
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Risk factors in African-Caribbean and European
men UK, aged 40-64
plt0.05
Chaturvedi et al, 1993
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African-Caribbean Blacks

• Lower risk of CHD death than whites
• Higher risk of stroke death than whites
• But hypertension common (50 in gt 40 year olds)
• High risk of complications of hypertension
  (stroke, renal failure, LVH)
• Differences in response to antihypertensive drugs
• Sensitive to salt restriction, diuretics, CCBs
• Less responsive than whites to ACE-i and
  ß-blockers
• 2-fold increased risk of diabetes

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British South Asians

• Higher risk of death from CHD and stroke than
  whites
• Hypertension common
• High prevalence of type II diabetes
• Insulin resistance common
• Central obesity
• Diabetes, elevated fasting glucose
• Low HDL cholesterol
• High triglycerides
• High CVD risk (1.5 x risk calculated using charts)

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Who should receive cardiovascular risk factor
treatment?Primary vs. Secondary prevention?
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Facts about coronary artery disease

• Only 20 of coronary events are preceded by
  long-standing angina
• 57 of men 64 of women who die suddenly of CHD
  have had no prior symptoms
• In 62 of men and 46 of women the first sign of
  CAD is MI or death
• Only 70 survive their first CAD event

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• The difference between primary and secondary
  cardiovascular disease prevention is about
• 2 minutes

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Benefits of treating known coronary risk factors
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Statins CHD preventionHeart Protection Study


HPS, Lancet 2002
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Lipid lowering - statins CHD preventionAnglo-Sc
andinavian Cardiac Outcomes Trial
Lipid-Lowering Arm
Lancet 2003 361 1149-58
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Cholesterol targets

• Total cholesterol lt 4 mmol/l
• Non-HDL lt 3 mmol/l
• LDL cholesterol lt 2 mmol/l
• HDL gt 1 mmol/l

BHS JBS Guidelines
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BP lowering treatment and cardiovascular
riskMeta-analysis of trials of BP lowering in
mild-moderate hypertension
Collins et al, Lancet 1990
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Benefits of BP lowering are proportional to BP
reductions/differences
Stroke
Coronary heart disease
1.50
1.50
1.50
1.50
1.25
1.25
1.25
1.25
1.00
1.00
1.00
1.00
Relative risk of stroke
Relative risk of stroke
Relative risk of CHD
Relative risk of CHD
0.75
0.75
0.75
0.75
0.50
0.50
0.50
0.50
0.25
0.25
0.25
0.25
-
10
-
8
-
6
-
4
-
2
0
2
4
-
10
-
8
-
6
-
4
-
2
0
2
4
-
10
-
8
-
6
-
4
-
2
0
2
4
-
10
-
8
-
6
-
4
-
2
0
2
4
Systolic blood pressure difference
Systolic blood pressure difference
Systolic blood pressure difference
Systolic blood pressure difference
between randomised groups (mmHg)
between randomised groups (mmHg)
between randomised groups (mmHg)
between randomised groups (mmHg)
Lancet 2003
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Whats new?
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Hypertension in the Very Elderly Trial (HYVET)

• 3845 subjects aged 80 years
• SBP 160 mmHg
• Randomised to indapamide perindopril or placebo
• Target BP 150/80 mmHg
• Median follow-up 1.8 years
• Reduced risk of
• Stroke (30, p0.06)
• Stroke death (39, p0.05)
• Any death (21, p0.02)
• Heart failure (64, plt0.001)

Beckett et al, NEJM 2008
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Blood pressure targets

• Non-diabetics
• Optimal SBP lt140, DBP lt85 mmHg
• Audit standard lt150/90 mmHg
• Diabetics
• Optimal BP lt130/80 mmHg
• Audit standard lt140/80 mmHg

Joint British Society guidelines, 2006
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Effect of smoking cessation on myocardial
re-infarction
Continued to smoke (n174) Stopped smoking (n
231)
Cumulative percentage of non-fatal reinfarction
Months
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Lifestyle interventions risk factors

• Weight loss reduces BP
• Short-term studies of diet, exercise or both
• 5.1kg weight loss ? 4.4/3.6 mmHg BP ?
• Long-term studies (?2 years)
• 10kg weight loss ? 6.0/4.6 mmHg BP ?
• Alcohol moderation reduces BP
• Meta-analysis of 15 trials, n2234
• Reduced intake ? 3.3/2.0 mmHg BP ?
• Dose-response relationship

Neter et al. Hypertension 2003 Aucott et al.
Hypertension 2005
Xin. Hypertension 2001
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• More
• Fresh fruit vegetables
• Whole grain products
• Fish poultry
• Nuts
• Low-fat dairy foods
• Unsaturated oils
• High
• Magnesium, potassium calcium

• Less
• Saturated fat
• Cholesterol
• Total fat
• Salt
• Processed foods

http//www.nhlbi.nih.gov/health/public/heart/hbp/d
ash/
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Effects of DASH diet on BP
Control typical US diet
-2.8 mmHg
Combination diet fruit, veg, low-fat dairy,
low in saturated total fat Effect greater in
hypertensives than normotensives
-5.5 mmHg
-1.1 mmHg
-3.0 mmHg
DASH. Appel et al. NEJM 1997
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Recommended daily salt intake

• Salt intake lt 100 mmol/day
• NaCl lt6 g/day
• Na lt2.4 g/day

Estimated typical US consumption 143 mmol/day
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Effect of modest salt restriction on BP
Change in SBP (mmHg)
Change in urinary sodium (mmol/24 hours)
Cochrane Collaboration 2005
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. but a little alcohol is good for the heart
Relative risk of CHD by alcohol intake
Relative risk of CHD
Units /week
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Dose-response relationship between physical
activity health benefit
Haskell, Med Sci Sports Exerc 1994
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Effects of non-pharmacological interventions on BP
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CHD risk factor management

• How do we do?

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Secondary prevention in high risk (CHD)
patientsEUROASPIRE I, II III
Prevalence of risk factors ()
Obesity
Diabetes
Smokers
BP ? 140/90
TC ? 5mmol/l
European Society of Cardiology 2007
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Conclusions

• Major risk factors for CHD are known
• Treating these risk factors is possible
• Treating risk factors reduces risk of
• CHD events mortality
• Other cardiovascular events
• We can do better

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