Another obesity myth debunked

November 13, 2013 - 06:56

Cardiovascular disease is caused exclusively by overweight and obesity, major new study reveals.

You may well have healthy levels of blood sugar, cholesterol and blood pressure, but if you’re overweight, you still have an increased risk of cardiovascular disease, according to a new Danish study. (Photo: Shutterstock)

Doctors and researchers have long believed that obesity in itself does not increase obese people’s risk of cardiovascular disease.

It has been assumed that the risk of cardiovascular disease only increases if the obese person also has metabolic disorders such as high blood pressure, high cholesterol or high blood sugar.

This has meant that obese people have had a reason to feel safe, health-wise, as long as they do not suffer from any of the metabolic disorders.

This assumption is however entirely wrong, according to a comprehensive new study.

Obesity increases risk of cardiovascular disease

In the study of some 71,500 Danes, the researchers show that obesity and overweight in themselves are almost exclusively responsible for obese people’s increased risk of cardiovascular disease.

This can have serious consequences in the future:

“In recent years we have seen a reduction in the many factors that contribute to an increased risk of cardiovascular disease: smoking, cholesterol levels, high blood pressure and so on. That’s all good and well; however, our study shows that we have overlooked another important risk factor – obesity itself,” says Clinical Professor Børge Nordestgaard of the Department of Clinical Medicine, Herlev Hospital and the University of Copenhagen, Denmark.

“If we don’t do something about this factor, our study shows that we can expect an explosion in the number of cases of cardiovascular disease in the future.”

"Our study shows that we have overlooked another important risk factor – obesity itself. If we don’t do something about this factor, our study shows that we can expect an explosion in the number of cases of cardiovascular disease in the future.
Børge Nordestgaard

The study is published in the journal JAMA Internal Medicine.    

Almost 72,000 participants

The researchers examined 71,527 individuals from the Copenhagen General Population Study and categorised them according to body mass index (BMI) as normal weight, overweight, or obese and according to the absence or presence of metabolic syndrome.

By combining this data with data from the Danish National Hospital Discharge Register, the researchers could see which of the examined individuals had been hospitalised with cardiovascular disease and which ones have died as a result of e.g. myocardial infarction or blood clots.

”This is the largest single study of its kind,” explains the professor. “It is unique for Denmark that we can carry out studies of this magnitude. We can do this because we can combine comprehensive studies such as the Copenhagen General Population Study with data from the National Hospital Discharge Register.”

Here are the risk groups

The results of the study made it clear that both overweight people with a BMI of between 25 and 29.9 and obese people with a BMI of above 30 have an increased risk of developing cardiovascular disease.

This applied to both groups of participants, i.e. those with and those without metabolic syndrome, leaving the researchers to conclude that overweight and obesity in themselves trigger an increased risk of cardiovascular disease.

“Our study actually shows that the metabolic disorders only slightly increased the risk of cardiovascular disease. The main cause of an increased risk was without a doubt overweight or obesity.”

Nordestgaard believes that the reason for the increased risk can be found in other obesity-related illnesses that have an effect on the metabolic disorders, for instance increased inflammation in the body.

The obesity epidemic needs to be curbed
This means that there is no longer any excuse for not knowing about the increased risk. If you are overweight, you have an increased risk. It’s as simple as that.
Børge Nordestgaard

The new study opens up a number of new perspectives.

Firstly, according to the professor, it should be clear that a lot of work still needs to be done by society and politicians to curb the obesity epidemic if we want to avoid it being replaced by a cardiovascular disease epidemic in the future.

“It is important for society to prioritise any initiatives that can prevent a cardiovascular epidemic,” he says.

Secondly, the study also shows that an assessment of the risk of cardiovascular disease does not necessarily need to include measurements of blood pressure, cholesterol levels and blood sugar. According to the study, a person’s BMI is a much better parameter for assessing the risk of cardiovascular disease.

“This means that there is no longer any excuse for not knowing about the increased risk. If you are overweight, you have an increased risk. It’s as simple as that.”

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Read the Danish version of this article at videnskab.dk

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