Years before developing diabetes, people with insulin resistance could be more likely to develop abnormal heart rhythms, which may put them at greater risk of sudden death, according to research we’ve funded and presented today at the British Cardiovascular Society conference.
Doctors have known for many years that people with diabetes are at higher risk of sudden death. Researchers from University College London wanted to understand whether this was linked to insulin resistance, which precedes diabetes.
Using data from 1,448 people aged 60-64, they found an association between signs of insulin resistance and markers which indicate an increased risk of developing dangerous arrhythmias, a problem with the rate or rhythm of the heartbeat. These arrhythmias may increase the risk of sudden cardiac death, where the heart suddenly stops beating.
Changes to electrical activity in the heart
Using blood samples and electrocardiograms (ECGs, which measure the electrical activity of the heart), they found that low levels of the hormones leptin and insulin-like growth factor 1, which are signs of insulin resistance, were strongly associated with a prolonged QT interval measured on an ECG.
The QT interval represents the time it takes for the ventricles (the two larger chambers of the heart) to contract to pump blood out of the heart and then relax. When the QT interval is too long it increases the risk that a person will develop an abnormal and dangerous heart rhythm, and this can lead to sudden death. People with diabetes are also more likely to have a prolonged QT interval.
Insulin resistance often has no symptoms so people may be unaware they have developed it. It develops when cells in your muscles, fat and liver don’t respond well to insulin. This affects how they’re able to take up glucose (sugar) from the blood, meaning levels of glucose in the blood remain too high, forcing the pancreas to work extra hard to keep levels down.
This is the largest study to date to show that people with insulin resistance, who are otherwise apparently healthy, may be at higher risk of developing dangerous arrhythmias, and therefore sudden death.
Dr Sonya Babu-Narayan, our Associate Medical Director and Cardiologist, said:
“Understanding the link between insulin resistance and heart rhythm disturbances is particularly important as insulin resistance can be diagnosed, prevented and potentially reversed.
“However, many people won’t know that they have insulin resistance until it has developed into diabetes. We need to make it easier for people to maintain a healthy diet, weight and to get more exercise to reduce their risk of developing it.”
Find out about our risk factor research