Influenza vaccination is associated with a lower risk of dementia in patients with heart failure, according to research presented at Heart Failure 2016 and the World Congress on Acute Heart Failure in Florence.

“Previous studies have shown that there is a link between impairment in cognitive function and heart failure,” said lead author Ju-Chi Liu, director of the division of cardiovascular medicine, Taipei Medical University.

“Some reports have also suggested that inflammation after getting the flu might contribute to dementia. However, there are no solid data to demonstrate that influenza vaccination could decrease the relative risk of dementia in patients with heart failure.”

The 2000-2012 study included 20,509 Taiwanese patients over 60 years of age with a diagnosis of heart failure. Of those, 10,797 received at least one influenza vaccination during the 12-year follow-up.

After adjusting for confounders, heart failure patients who had received the flu vaccine were 35 per cent less likely to develop dementia than those who had not been vaccinated. Those who had been vaccinated more than three times had a 55 per cent lower dementia risk.

Vaccinated heart failure patients had a 44 per cent lower risk of dementia if they were over 70 years old and a 26 per cent lower risk if they were between 60 and 69 years old. Vaccinated male and female heart failure patients had a 40 and 31 per cent lower risk of dementia respectively.

“We think that the flu virus can activate the immune response and cause inflammation, which may injure the brain cells,” said Dr Liu. “Respiratory infection during flu can induce changes in blood pressure and heart rate, referred to as an unstable haemodynamic status, which may also harm the brain tissue. These effects of the flu could play a role in the development of dementia, particularly in heart failure patients who already have impaired circulation in the brain,” added Dr Liu.

“The flu shot not only decreases the risk of respiratory infection and death from pneumonia, but may also decrease the risk of dementia in the future.”