INTERHEART was the first major international study to investigate the primary causes of heart attacks, worldwide. It investigated the causes of heart attacks among 15,000 people, all of whom had their first heart attacks. The purpose of the INTERHEART study was to discover the factors that contributed the most to having heart attacks, and consider ways that this information could be used to reduce heart attacks, by reducing these risk factors.
Their main finding was good news for all of us: up to 90% of your risk of having a heart attack CAN be reduced! Dr Salim Yusef of McMaster University was the Principal Investigator, and results were published in the Lancet in 2004 (Yusef S, et al, 2004). These researchers started with investigating eleven risk factors, and of the 11 factors nine were found to contribute directly to whether you subjects had heart attacks. More exciting was the fact that ALL of the nine were MODIFIABLE risk factors.
What that means is that when you change YOUR level of the risk factor, you have reduced your chances of having a heart attack! For example, if you change one of your risk factors from a ‘High Risk’ down to a Low or Moderate Risk, you have reduced the likelihood of having a heart attack correspondingly.
The key to prevention is finding YOUR BIGGEST RISK FACTORS, and reducing those. What ARE the modifiable factors that predicted whether you might have a heart attack?
Five were no surprise; they were the traditional risk factors of smoking, high cholesterol, high blood pressure, diabetes and physical inactivity. In addition, INTERHEART found another two NEW risk factors not previously appreciated. These two new non-traditional risk factors were chronic STRESS and abdominal obesity. And these two new factors are particularly relevant to understanding total risk in North America and Western Europe!
How much IMPACT does STRESS have compared with other medical risk factors?
As you might expect, Cholesterol and Smoking are still the top two heart attack risks, worldwide. The third most important factor worldwide was a surprise – IT was stress.
In fact, worldwide, the impact of stress and smoking were almost identical. I’m sure we have all heard someone say “My doctor told me I have to quit smoking, or I’ll have a heart attack”; but how many have heard your doctor warn you “Your stress will kill you with a heart attack.”
In North America abdominal obesity was the single greatest risk factor. After that, cholesterol and stress accounted for an equal number of heart attacks! IF you doctor were to decide to allocate his time with you based ONLY on the potential for reducing YOUR risk of having a heart attack, he or she would spend as much time assessing and reducing your STRESS RISKS as they currently spend on reducing cholesterol risks.
After the three Top Tier factors, of Cholesterol, Smoking and Stress, the second tier of four factors each accounted for ONLY about HALF AS MUCH Prevalence Adjusted Risk (or PAR) as any of the top three. For example, abdominal obesity, worldwide, accounted for 20% of prevalence adjusted risk; high blood pressure accounted for 18% of your risk; and diabetes accounted for another 10%.
How many of you would have guessed that STRESS would be responsible for as many heart attacks as high blood pressure and diabetes combined?
Finally, physical inactivity accounting for about 12%, and eating vegetables REDUCED the risk of a heart attack by about 14%. Combined, physical activity and good diet could reduce your total risk by about 26%, but an effective stress reduction program could lower risk by over 30%! Think of it this way: you could start exercising three times a week today AND begin a healthy diet, eating vegetables daily, and you would STILL be more likely to have a heart attack than if you targeted stress reduction as your primary prevention focus.
So, what did INTERHEART teach us? It told us that heart attacks are more preventable than anyone thought. 90% of YOUR RISK is accounted for by NINE things; and 9 things that YOU CAN CHANGE!
INTERHEART taught us that risk can be measured. Some risk factors, like Cholesterol levels, are easily measured through standard medical tests. Others, like stress, can be assessed with questionnaires that have been tested in large population studies and have related response levels to actual occurrences of heart attacks, across a decade or more.
Because doctors are not familiar with these, they don’t usually use them. But what if you had access to them, and could determine YOUR risk?
INTERHEART also taught us that risks are cumulative. If you want to reduce ALL your risks, you should MEASURE ALL your greatest risk factors. Finally, INTERHEART taught us that risks can be reduced. You can DO something about ALL of these risks. To conclude, Stress is a Top Tier Risk for heart attacks and you now have a way of assessing your risk from stress in your life.
If you have heart disease it is almost certain that stress plays some part in your risk profile. You MUST evaluate your stress risk, IF you want to reduce ALL your major risks. HeartStressRisk.com will help you understand, assess, and change your stress risks. Can you reduce your stress risk? Complete the Heart Stress Profile now, to find what YOUR heart stress risk is!
To read more please go to the INTERHEART website at: http://www.phri.ca/interheart/
Yusuf S, Hawken S, Ôunpuu S, Dans T, et al. (2004) Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study): case-control study. The Lancet, 364, 9438, 937-52.
Rosengren A, Hawken S, Ôunpuu S, et al (2004) Association of psychosocial risk factors with risk of acute myocardial infarction in 11,119 cases and 13,648 controls from 52 countries (the INTERHEART study): case-control study. The Lancet, 364: 953–62.