May 23, 2016, European Society of Cardiology -- Influenza vaccination is associated with a lower risk of dementia in patients with heart failure, according to a study in more than 20 000 patients presented today at Heart Failure 2016 and the 3rd World Congress on Acute Heart Failure by Dr Ju-Chi Liu, director of the Division of Cardiovascular Medicine, Department of Medicine, Taipei Medical University - Shuang Ho Hospital, in New Taipei City, Taiwan.1

"Previous studies have shown that there is link between impairment in cognitive function and heart failure," said Dr Liu. "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 current study investigated whether heart failure patients who had received the flu vaccine had a lower risk of dementia. The study included all patients over 60 years of age who visited healthcare facilities in Taiwan with a diagnosis of heart failure during 2000 to 2012. Those who had dementia prior to being diagnosed with heart failure were excluded from the study. Patients were recruited from the National Health Insurance Research Dataset, which holds information on 98% of Taiwan residents.
The study included 20 509 patients with heart failure. Of those, 10 797 received at least once vaccination against influenza and the other 9712 were not vaccinated during the 12 year follow-up period.

After adjusting for factors that might influence the association, the investigators found that heart failure patients who had received the flu vaccine were 35% less likely to develop dementia than those who had not been vaccinated. Those who had been vaccinated more than three times had a 55% lower dementia risk.

"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.

He continued: "Vaccination reduces the chance of getting the flu, which means that the associated immune activation, inflammation and unstable haemodynamic status do not occur. This could explain the reduced risk of developing dementia. The more vaccinations patients received, the less chance they had of getting the flu, which might be why they had an even lower risk of dementia."

European Press Room Homepage