Cardiovascular diseases such as heart attacks and strokes are among the leading causes of death worldwide. It is known that certain factors significantly increase the risk of such diseases. Researchers now report that modifiable risk factors are responsible for half of cardiovascular diseases.
Scientists have been able to prove that the five classic cardiovascular risk factors – obesity, high blood pressure, elevated cholesterol levels, smoking and diabetes mellitus – are directly related to more than half of all cardiovascular diseases worldwide. The study results were published in the New England Journal of Medicine.
Five classic cardiovascular risk factors
According to a statement from the University Hospital Hamburg-Eppendorf (UKE), a good third of all deaths worldwide are due to cardiovascular diseases.
These often develop insidiously over decades: Often unnoticed, the vessel walls change and arteriosclerosis (hardening of the arteries) develops, which can result in coronary heart disease (CHD) and its complications such as a heart attack, acute cardiac death or a stroke.
Researchers from the Global Cardiovascular Risk Consortium under the leadership of the Department of Cardiology at the University Heart and Vascular Center of the UKE and the German Center for Cardiovascular Research (DZHK) have now been able to prove that the five known classic cardiovascular risk factors are directly related to the half of all cardiovascular diseases.
“Our study clearly shows that more than half of all heart attacks and strokes can be avoided by controlling and treating the classic risk factors,” says Prof. Dr. Stefan Blankenberg, Medical Director of the University Heart and Vascular Center of the UKE.
“These results are of the utmost importance if we want to strengthen prevention in this area. At the same time, around 45 percent of cardiovascular disease worldwide is not explained by these risk factors and should motivate us and academic funders to continue research efforts.”
Data from around 1.5 million people
The Global Cardiovascular Risk Consortium analyzed the individual data of approximately 1.5 million people from 112 cohort studies drawn from 34 countries in the eight geographic regions of North America, Latin America, Western Europe, Eastern Europe and Russia, North Africa and the Middle East, Sub-Saharan Africa, Asia and originate from Australia.
The aim of the study was to gain a better understanding of the global distribution, the importance of the individual risk factors and their effects on cardiovascular diseases and overall mortality in order to derive targeted preventive measures.
“In principle, the five classic risk factors examined can be modified and are therefore accessible for preventive measures. So far there have been conflicting study results as to what proportion of cardiovascular diseases is actually explained by these risk factors,” says the first author, Priv.-Doz. dr Christina Magnussen, Clinic for Cardiology in the University Heart and Vascular Center of the UKE.
Significant proportion still unexplained
The study showed differences in the prevalence of risk factors across the eight global regions. The researchers saw the highest values for obesity in Latin America, for high blood pressure and elevated cholesterol levels in Europe.
Smoking is a risk factor, particularly in Latin America and Eastern Europe, and diabetes mellitus in North Africa and the Middle East.
All five risk factors (obesity, high blood pressure, high cholesterol, smoking and diabetes mellitus) together explain 57.2 percent of the cardiovascular risk in women and 52.6 percent of the cardiovascular risk in men.
This means that a significant proportion of the cardiovascular risk has not yet been clarified. In comparison, the five risk factors only explain around 20 percent of the risk of dying (all-cause mortality).
Importance decreases with age
The study also makes it clear that elevated blood pressure or elevated cholesterol levels are linearly related to the occurrence of cardiovascular disease: the higher the values, the higher the probability of the occurrence of cardiovascular disease. This result applies to all global regions examined.
The scientists also found a remarkable connection between cholesterol levels and overall mortality: Both very low and high cholesterol levels cause increased overall mortality.
The importance of all risk factors decreases with age, for example, high blood pressure is more harmful for 40-year-olds than for 80-year-olds. The only exception is the body mass index (BMI), which is equally important at any age.
“This raises the question to what extent the target values for the treatment of cardiovascular risk factors in old age should be identical to those in middle to old age,” says Prof. Blankenberg.
high blood pressure is particularly problematic
The study provides a comprehensive data set to prevent cardiovascular disease or reduce its consequences in people at cardiovascular risk or patients with cardiovascular disease by improving lifestyle and lowering elevated blood pressure or cholesterol levels.
“An elevated systolic blood pressure explains most of the cardiovascular risk,” says Priv.-Doz. dr magnussen
The expert points out that special attention should be paid to the therapy of patients with high blood pressure “in order to avoid cardiovascular diseases as far as possible”. (ad)