Incidence and prevalence

Mortality rates¹

• Coronary heart disease (CHD) is the most common cause of death (and premature death) in the UK.
• 1 in 5 men and 1 in 7 women die from CHD.
• There are 94,000 deaths from CHD in the UK each year.
• Death rates from CHD have fallen by 45% for people aged under 65 years in the last 10 years. This fall is fastest in those aged 55 years and over. It is largely due to a reduction in major risk factors (mostly smoking) and improvement in treatment and secondary prevention. The fall is not as high as that in some other countries such as Australia (48%) and Norway (54%).
• Death rates from CHD are highest in Scotland, and the North of England, and lowest in the South of England. For more than 25 years these rates have been consistently highest in Scotland.
• Death from CHD is more likely during winter; in 2004/2005, just under 7,000 people died from CHD in England and Wales each month in June and July, compared with around 9,000 in December and January.

Morbidity rates²

• The average incidence of myocardial infarction is 600 per 100,000 in men aged 30-69 and 200 per 100,000 in women. The incidence increases with age.
• There are about 52,000 new cases of angina per year in all men living in the UK and about 43,000 new cases in women.
• About 4% of men and 0.5% of women in the UK have had a heart attack. Prevalence increases with age and is higher in men.
• 8% of men and 3% of women aged 55 to 64 years and about 14% of men and 8% of women aged 65 to 74 years have, or have had, angina.
• The prevalence of CHD in Britain according to Quality and Outcomes Framework (QOF) data was 3.7% of all GP registrations. The prevalence of CHD was higher in Scotland (4.6%) than in Wales (4.3%) or England (3.5%).
• The prevalence is higher in the North of England and Wales than in the South of England.
• The prevalence is higher in lower socioeconomic groups.
• Of note, mortality from CHD is falling but morbidity appears to be rising.

Risk factors

The aetiology of CHD is multifactorial. It is the result of interaction between genetic, lifestyle and environmental factors.

Age

• CHD increases with age. This is a non-modifiable risk factor.

Gender

• Traditionally, CHD has been considered a disease of men. However, CHD is the leading cause of death in both men and women.³
• It is responsible for a third of all deaths in women worldwide and half of all deaths in women over the age of 50 years in developing countries.⁴

Social deprivation

• In England and Wales there is a positive correlation between deaths from circulatory diseases and levels of deprivation.
• There is a marked difference in prevalence of coronary heart disease between and within communities.
• Men and women living in the West of Scotland are nearly six times more likely to die prematurely from CHD than men and women living in the South West of England.
• Within London, people living in Tower Hamlets have a three times increased risk of dying prematurely from CHD than those in Kensington and Chelsea.
• The difference in CHD rates in different socioeconomic groups is related to many factors, including diet, smoking, exercise, and alcohol.

Smoking

In 2001, 27% of adults aged 16 years and over smoked cigarettes in England; 28% of men and 25% of women.

• Mortality from CHD is 60% higher in smokers.⁵
• Regular exposure to passive smoking increases CHD risk by 25%.^6,7
• In 2000, about 1 in 8 deaths from cardiovascular disease (CVD) were attributable to smoking in the UK.
• World Health Organization (WHO) research estimates that over 20% of CVD is due to smoking.⁸

Poor nutrition

There are national, regional, socioeconomic and ethnic differences in nutrition.

• A WHO report in 2003 stated that a diet high in fat (particularly saturated fat), sodium and sugar and low in complex carbohydrates, fruit and vegetables increases the risk of CVD.⁹
• It has been recommended that the percentage food energy derived from fat should be 35%, with 11% from saturated fat. The National Diet and Nutrition Survey in 2000/2001 found that the total energy intake from fat was 36% in men and 35% in women with 13% from saturated fat. It also found that the average intake of fruit and vegetables was fewer than 3 portions per day compared with the recommended 5 portions.¹⁰ In the same survey salt intake was 11 g per day for men and 8.1 g for women. However, the Scientific Advisory Committee on Nutrition suggests that salt intake should be no more than 6 g per day.
• Trans fatty acids reduce high-density lipoprotein (HDL) and increase low-density lipoprotein (LDL) cholesterol and can increase CHD risk. A meta-analysis showed that a 2% increase in the energy intake from trans fatty acids increased CHD incidence by 23%.¹¹
• Eating oily fish rich in omega-3 fatty acids has been shown to reduce CHD mortality.¹²
• Increased intake in dietary fibre also appears to reduce risk.

Infrequent exercise

• Physical activity reduces the risk of CHD.
• The 2002 World Health Report estimated that over 20% of CHD in developed countries was due to physical inactivity.⁸
• Recommended physical activity levels are 30 minutes of moderate physical activity on 5 or more days per week.¹³
• Over one third of UK adults are estimated to be inactive (exercised for less than one occasion of 30 minutes per week).

Alcohol

• 1 to 2 units of alcohol per day reduce the risk of CHD. Alcohol increases HDL cholesterol and reduces thrombotic risk. Higher levels of consumption increase risks from other causes.¹⁴
• The World Health Report in 2002 estimated that 2% of CHD in men in developed countries is due to excessive alcohol consumption.⁸
• Men should drink no more than 3 to 4 units on any one day and women no more than 2 to 3 units.

Psychosocial wellbeing

• Work stress, lack of social support, depression, anxiety and personality (particularly hostility) can all increase CHD risk.¹⁵

Blood pressure

• For adults aged 40 to 69 years, each 20 mm Hg rise in usual systolic blood pressure or 10 mm Hg rise in diastolic blood pressure doubles the risk of death from CHD.¹⁶
• The INTERHEART study showed that 22% of heart attacks in Western Europe were due to a history of high blood pressure and those with hypertension had almost twice the risk of a heart attack.¹⁷

Cholesterol

• CHD risk is related to cholesterol levels.
• The INTERHEART study suggested that 45% of heart attacks in Western Europe are due to abnormal blood lipids.¹⁷
• People with low levels of HDL cholesterol have an increased risk of CHD and a worse prognosis after a myocardial infarction.
• In the UK, it is suggested that the target cholesterol is < 4 mmol/L for people with diabetes or established CVD or for people at high risk of developing CVD. People with HDL cholesterol <1 mmol/L should also be considered for treatment.¹⁸

Overweight and obesity

• Obesity is an independent risk factor for CHD. It is also a risk factor for hypertension, hyperlipidaemia, diabetes and impaired glucose tolerance.
• Central or abdominal obesity is most significant. Those with central obesity have over twice the risk of heart attack.¹⁷

Diabetes

• Men with type 2 diabetes have a 2 to 4 times greater annual risk of CHD; women have a 3 to 5 times greater risk.¹⁹
• Over 4% of men and 3% of women in England have diagnosed diabetes. The prevalence is increasing.

Ethnicity

• South Asians living in the UK (people from India, Pakistan, Bangladesh and Sri Lanka) have a higher premature death rate from CHD (46% higher for men; 51% higher for women).¹
• Hypotheses for this include migration, disadvantaged socioeconomic status, 'proatherogenic diet', lack of exercise, high levels of homocysteine and lipoprotein(a) (Lp(a)), endothelial dysfunction and enhanced plaque and systemic inflammation.²⁰
• The premature death rate from CHD in West Africans and people from the Caribbean is much lower (half the rate compared with the general population for men and two-thirds of the rate for women).

Family history

• First-degree relatives of patients with premature myocardial infarction have double the risk themselves.²¹
• Premature CHD is that before age 55 years in men and 60 years in women.
• More than one third of admissions for premature myocardial infarction could be prevented by screening and treating first-degree relatives.²¹
• Genetic predisposition and shared lifestyle are likely to contribute.
• Several regions of the human genome have been shown to be associated with either CHD or hypertension.

Serum homocysteine

• It was previously thought that elevated levels of homocysteine is an independent risk factor for IHD, likely due to oxidative damage to the endothelium, platelet activation and thrombus formation. The theory was that dietary supplementation with folic acid could reduce homocysteine levels and therefore CHD incidence.
• A meta-analysis in 2005 disputed this.²²

Economic cost²³

• In 2006, CVD cost the healthcare system in the UK around £14.4 billion. This represents a cost per capita of just under £250. The cost of hospital care for people who have CVD accounts for about 72% of these costs, whereas 20% of the cost is due to drugs.
• In 2006, production losses due to mortality and morbidity associated with CVD cost the UK over £8.2 billion, with around 55% of this cost due to death and 45% due to illness in those of working age.

Public health targets

Three-year average mortality rates for circulatory diseases (ages under 75 years) for England have fallen by 44.0% since the baseline. The minimum target requirement for a 40% reduction by 2009-2011 has been met, ahead of schedule.²⁴

The absolute gap in mortality rates for circulatory diseases (ages under 75 years) between the Spearhead Group and England as a whole, has reduced by 35.9% since the baseline, compared with the required target reduction of 40% by 2009-2011. The Spearhead Group consists of the 70 local authority areas that are in the bottom fifth nationally for 3 or more of the following 5 factors: male life expectancy at birth, female life expectancy at birth, cancer mortality rate in the under-75s, CVD mortality rate in the under-75s and the Index of Multiple Deprivation (2004).

Document references

1. Coronary heart disease statistics. Mortality. 2008 edition
2. Coronary Heart disease statistics. Morbidity. 2008 edition
3. Mikhail GW; Coronary heart disease in women. BMJ. 2005 Sep 3;331(7515):467-8.
4. Pilote L, Dasgupta K, Guru V, et al; A comprehensive view of sex-specific issues related to cardiovascular disease. CMAJ. 2007 Mar 13;176(6):S1-44. [abstract]
5. Doll R, Peto R, Boreham J, et al; Mortality in relation to smoking: 50 years' observations on male British doctors. BMJ. 2004 Jun 26;328(7455):1519. Epub 2004 Jun 22. [abstract]
6. Law MR, Morris JK, Wald NJ; Environmental tobacco smoke exposure and ischaemic heart disease: an evaluation of the evidence. BMJ. 1997 Oct 18;315(7114):973-80. [abstract]
7. He J, Vupputuri S, Allen K, et al; Passive smoking and the risk of coronary heart disease--a meta-analysis of epidemiologic studies. N Engl J Med. 1999 Mar 25;340(12):920-6. [abstract]
8. Guilbert JJ; The world health report 2002 - reducing risks, promoting healthy life. Educ Health (Abingdon). 2003 Jul;16(2):230.
9. Diet, Nutrition and the prevention of chronic diseases. World Health Organization, 2003; Report of a Joint AHO/FAO Expert Consultation
10. NHS; 5 (fruit and vegetables) a day
11. Mozaffarian D, Katan MB, Ascherio A, et al; Trans fatty acids and cardiovascular disease. N Engl J Med. 2006 Apr 13;354(15):1601-13.
12. Bays HE, Tighe AP, Sadovsky R, et al; Prescription omega-3 fatty acids and their lipid effects: physiologic mechanisms of action and clinical implications. Expert Rev Cardiovasc Ther. 2008 Mar;6(3):391-409. [abstract]
13. Recommended amount of physical activity, World Health Organization. Accessed May 2010
14. Safe Alcohol Consumption; A Comparison of Nutrition and Your Health: Dietary Guidelines for Americans and Sensible Drinking
15. Brezinka V, Kittel F; Psychosocial factors of coronary heart disease in women: a review. Soc Sci Med. 1996 May;42(10):1351-65. [abstract]
16. Lewington S, Clarke R, Qizilbash N, et al; Age-specific relevance of usual blood pressure to vascular mortality: a meta-analysis of individual data for one million adults in 61 prospective studies. Lancet. 2002 Dec 14;360(9349):1903-13. [abstract]
17. Yusuf S, Hawken S, Ounpuu S, et al; Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study): case-control study. Lancet. 2004 Sep 11-17;364(9438):937-52. [abstract]
18. No authors listed, JBS 2: Joint British Societies' guidelines on prevention of cardiovascular disease in clinical practice. Heart. 2005 Dec;91 Suppl 5:v1-52.
19. Garcia MJ, McNamara PM, Gordon T, et al; Morbidity and mortality in diabetics in the Framingham population. Sixteen year follow-up study. Diabetes. 1974 Feb;23(2):105-11.
20. Kuppuswamy VC, Gupta S; Excess coronary heart disease in South Asians in the United Kingdom. BMJ. 2005 May 28;330(7502):1223-4.
21. Chow CK, Pell AC, Walker A, et al; Families of patients with premature coronary heart disease: an obvious but neglected target for primary prevention. BMJ. 2007 Sep 8;335(7618):481-5.
22. Lewis SJ, Ebrahim S, Davey Smith G; Meta-analysis of MTHFR 677C->T polymorphism and coronary heart disease: does totality of evidence support causal role for homocysteine and preventive potential of folate? BMJ. 2005 Nov 5;331(7524):1053. Epub 2005 Oct 10. [abstract]
23. Coronary heart disease statistics. Economic costs. 2008 edition
24. Mortality Target Monitoring: Update to include data for 2007, Dept of Health, Oct 2008

Acknowledgements