For some time, researchers have identified abdominal obesity as an important risk factor for having a heart attack.

Now, new findings suggest that heart attack survivors who carry excessive belly fat around their waist are at an increased risk for a second or third heart attack. The risk for a subsequent stroke or heart attack was significant despite medication that is supposed to control cardiovascular health.

Extra pounds and strokes go hand in hand. But belly fat, in particular, was much less studied.

Before the research team in Europe performed this study, the association between abdominal obesity and the risk of a subsequent heart attack or stroke was largely unknown.

“Patients are typically put on a stringent medical treatment regimen after their first attack to prevent second events (called secondary prevention),” said study author Dr. Hanieh Mohammadi of the Karolinska Institute, Stockholm, Sweden. “Secondary prevention works through reducing risk factors associated with heart attack and stroke such as high blood sugar, lipids and blood pressure. It was previously unknown whether abdominal obesity is a risk factor for recurrent events among patients on secondary prevention treatments.”

The study involved more than 22,000 patients, part of the SWEDEHEART registry, whose medical condition was followed after their first heart attack for a median of 3.8 years.

In this cohort, 78% of men and 90% of women had abdominal obesity, defined as a waist circumference of 94cm or more for men and 80cm or above for women.

Remarkably, the results suggest that abdominal obesity was associated with fatal and non-fatal heart attacks and strokes, regardless of other risk factors such as smoking, diabetes, hypertension, blood pressure, and body mass index, but also independent of any secondary prevention treatment. In other words, belly fat is an individual risk factor, no necessarily connected to being overweight.

What’s more, waist circumference was found to be a more important predictor of subsequent heart attacks than overall obesity.

Abdominal obesity is closely linked with conditions that accelerate the clogging of arteries, but also conditions that caused increased blood pressure, high blood sugar, and insulin resistance.

“Our results, however, suggest that there may be other negative mechanisms associated with abdominal obesity that are independent of these risk factors and remain unrecognised,” Mohammadi added. “In our study, patients with increasing levels of abdominal obesity still had a raised risk for recurrent events despite being on therapies that lower traditional risk factors connected with abdominal obesity – such as anti-hypertensives, diabetes medication and lipid lowering drugs.”

The higher the waist circumference, the greater the risk of a subsequent heart attack — and this relationship was stronger and more linear in men. In women, this relationship plotted a U-shaped graph, meaning that mid-range waist circumference was the least risky.

“Some studies have suggested that abdominal obesity may be more directly associated with the evil visceral fat (fat that sits around your organs) in men compared to women. In women it is thought that a greater portion of the abdominal fat is constituted by subcutaneous fat which is relatively harmless,” Dr. Mohammadi said, explaining why results differ so much between the sexes.

The findings, which were published in the European Journal of Preventive Cardiology, highlight the dangers of abdominal fat, which all people should strive to reduce to the best of their ability. After their first stroke, many patients feel more confident about their health outcomes because they start taking medication. But this study shows that if they have significant abdominal fat, they are still subjected to considerable risk of heart attack and stroke regardless of how many drugs they take.

Eating a healthy diet and regularly exercising are the best ways to reach an optimal waist circumference.