How do I assess my risk of having a heart attack?
We know now that disease (atherosclerosis) in the coronary arteries is the key risk factor in being predisposed to having a heart attack in the future. We also know the major risk factors that predispose to its development. Some of these are modifiable (such as stopping smoking, losing weight , controlling high blood pressure and cholesterol) others aren’t (age, male gender!)
So to assess risk we can either look directly at how extensive any individuals coronary artery disease is or indirectly look at all the risk factors for developing the disease. The downside of looking in isolation directly at the arteries is that it involves exposure to radiation and/or an invasive procedure with its attendant risks. It also doesn’t look at modifiable risk factors.
Risk factor tables looking at the likely hood of developing disease have been developed over the last 20 years. The first of these tables was derived from the inhabitants of a small American town of Framingham situated 21 miles west of Boston.
In 1948, the Framingham Heart Study embarked on an ambitious project in health research. At the time, little was known about the general causes of heart disease and stroke, but the death rates for cardiovascular disease (CVD) had been increasing steadily since the beginning of the century and had become an American epidemic. The objective of the Framingham Heart Study was to identify the common factors or characteristics that contribute to CVD by following its development over a long period of time in a large group of participants who had not yet developed overt symptoms of CVD or suffered a heart attack or stroke.
The researchers recruited 5,209 men and women between the ages of 30 and 62 from the town of Framingham, Massachusetts, and began the first round of extensive physical examinations and lifestyle interviews that they would later analyze for common patterns related to CVD development. Since 1948, the subjects have continued to return to the study every two years for a detailed medical history, physical examination, and laboratory tests, and in 1971, the Study enrolled a second generation – 5,124 of the original participants’ adult children and their spouses – to participate in similar examinations.
Over the years, careful monitoring of the Framingham Study population has led to the identification of the major CVD risk factors – high blood pressure, high blood cholesterol, smoking, obesity, diabetes, and physical inactivity – as well as a great deal of valuable information on the effects of related factors such as blood triglyceride and HDL cholesterol levels, age, gender, and psychosocial issues.
Tables have been derived to estimate individual patient’s chances of having a cardiovascular event. An example is shown opposite for non diabetic men.
Other calculating tools have been developed for other communities in particular in Britain. Here the risk of developing cardiovascular disease has been developed from the records of over 500 general practices. The QRISK calculator is thought to be the most accurate way of assessing risk.
Click here for example.
Is my risk good or bad?
The Framingham or Q risk calculator will tell you your chances of having a cardiovascular event (heart attack or stroke) and you will be compared to someone your age.
If you are at >10% risk of having a cardiovascular event over the next 10 years the government is happy for you to have a statin to lower the risk . They are even more happy if you exercise, eat healthily and don’t smoke! You can discuss statin treatment with your doctor (see comments on statins) and have some soul searching about your lack of fitness or otherwise!
As can be seen by the Framingham tables above if you are over 60 and a male you will have a risk of a cardiovascular event of greater than 10% in the next 10 years – the current treatment threshold for considering starting statins. If you are a male over 60 you may wish to consider whether you want a statin before visiting your GP next time.
A final note. The Q risk tables incorporate your post code in your overall assessment of risk. It may seem illogical that your chances of having heart disease are assessed as more or less depending if you live in one area compared to another. To a large extent this reflects poor lifestyle choices in one area compared to another. When I was in Glasgow I came to realise that the Glaswegians life expectancy was 4 years less than someone living in Edinburgh. I initially thought this maybe a reflection of the fried mars bars supplied in the fish and chip shops in Glasgow. It was probably due to the higher alcoholism/ drug abuse/ poverty rates in Glasgow. Some have argued the hardness of water or other environmental factors may be the relevant factor. Personally I do not believe that changing your post code per se is a modifiable risk factor for heart disease. So don’t move upmarket to help your heart!