Heart attack risk soars with just a few extra kilos
IT is the news we all feared: putting on just a few kilograms of fat can increase the risk of suffering a heart attack by nearly a fifth.
A study of almost 200 000 people has shown that a one-unit increase in body-mass index (BMI), which measures body fat levels, raises the risk of heart failure by 17%.
Until now, scientists suspected — but could not be certain — that extra body fat raised the chances of suffering heart disease.
For someone measuring 1.78m, one BMI unit is equivalent to 3kg; for someone who is 1.62m tall, it is the same as putting on 2.7kg.
The findings provide fresh evidence that obesity can cause heart disease, according to the researchers. They also found that an increase in body fat raised the risk of diabetes by 35% for every BMI unit.
“We knew already that obesity and cardiovascular disease often occur together,” said Dr Tove Fall, a researcher at Uppsala University in Sweden, who led the study with researchers at Imperial College London and the University of Oxford.
“However, it has been hard to determine whether increased BMI as such is dangerous. In this study we found that individuals with gene variants that lead to increased body-mass index also had an increased risk of heart failure and diabetes. The risk of developing diabetes was greater than was previously thought.”
The study, published in the journal PLOS Medicine, looked at FTO, a gene related to obesity that regulates appetite, in 198 502 people from across Europe.
Because genes are not affected by lifestyle or social factors, the analysis allowed the researchers to identify direct links between obesity and cardiovascular dis- ease. They found that the more copies of a defective variant of the FTO gene a person had, the higher their BMI was and the greater the risk of heart disease.
A defective variant of the FTO gene can lead to an increase in the BMI of individuals by between 0.3 and 0.4 units for each copy they have of it in their genome.
BMI is calculated by dividing a person’s weight in kilograms by their height in metres squared.
Those with a BMI of between 25 and 30 are considered to be overweight and those clocking in at higher than 30 are obese.
The researchers then looked at people with variants of these genes to see what their BMI was and whether they had suffered any heart disease, diabetes or other obesity-related diseases.
Obesity was also found to lead to higher levels of cholesterol, higher blood pressure, inflammation and fatty acids in the liver.
Professor Erik Ingelsson, who led the study at Uppsala University, said the variant of the FTO gene that causes increased BMI was common. “By using this new genetic method, we can now confirm that increased BMI contributes to the development of heart failure.”
Doctors have also warned that drinking too many fizzy drinks can cause irregular heartbeats.
A meeting of experts from the European Heart Rhythm Association heard the case of a woman who replaced water in her diet with fizzy drinks.
The 31-year-old was taken to hospital after fainting and was found to be suffering from potentially life-threatening irregular heartbeats.
Doctors discovered that she had drunk about two litres of cola each day since the age of 15. Tests revealed that her blood potassium levels were severely lowered and this was probably interfering with the way that the muscles in her heart were beating. A week after the patient stopped drinking cola and returned to drinking water, her potassium levels returned to normal.
Six similar examples of excessive cola consumption in medical literature were found, the meeting heard.
Previously reported symptoms in cases of excessive cola consumption included damaged skeletal muscle, arrhythmia and one death.
Professor Nadir Saoudi, who worked on the case, said it was important for “governments to ensure that bottled water is cheaper than sugary drinks, which is not always the case”.
“Excessive drinking of cola and other sugary beverages is likely to have additional adverse cardiovascular effects,” he said.