Survivors of childhood heart defects are more likely than the general population to develop dementia, including at earlier ages, researchers reported Feb. 12 in Circulation.

“Previous studies showed that people born with heart defects have a higher risk of neurodevelopmental problems in childhood, such as epilepsy and autism, but this is, to our knowledge, the first study to examine the potential for dementia later in adult life,” lead author Carina N. Bagge, BSc, a medical student in the Department of Clinical Epidemiology at Aarhus University Hospital in Aarhus, Denmark, said in a press release.

Using Denmark’s national databases, Bagge and colleagues studied 10,632 adults who were diagnosed with congenital heart disease (CHD) between 1963 and 2012. Each individual was then matched with 10 people from the general population with the same sex and birth year.

Compared to the general population, people with CHD had a 61 percent increased risk of dementia—with similar boosts in diagnoses for Alzheimer’s disease, vascular dementia and other forms of dementia. Diagnoses before age 65 were 2.6 times more likely among those with CHD, compared to only 30 percent more likely after age 65.

More severe CHD was associated with a greater risk of dementia in relation to the general population, spanning from 40 percent for CHD without extracardiac defects to a 100 percent increase for severe CHD, including univentricular hearts.

“Our study involved an older population born when treatments for heart defects were more limited,” Bagge said. “Modern treatment has improved greatly, and as a result we can’t directly generalize these results to children born today. We need further work to understand the risks in the modern era.”

However, the authors wrote their findings may still be relevant to the large population of adults currently living with CHD. There are approximately 1.4 million American adults living with a congenital heart defect, according to a 2016 study.

“In the absence of disease-modifying treatments for most dementias, the specific influence of etiologic factors on congenital heart disease is a potential target for future investigations to delay dementia onset in this vulnerable population,” Bagge et al. wrote.

Dementia and cognitive impairment is often progressive and can be caused by reduced blood flow to the brain and strokes, according to the release.

“Adults with CHD acquire cardiovascular morbidities earlier than members of the general population, which may impact the brain reserve,” the researchers wrote. “These morbidities, which include atrial fibrillation, stroke, diabetes mellitus, coronary artery disease, and heart failure, are associated with an enhanced risk of cognitive decline and dementia. We observed an increased relative risk among adults with CHD with and without acquired cardiovascular diseases or diabetes mellitus relative to their matched members from the general population.”

Bagge and colleagues said causation couldn’t be proven due to the observational design of their study. In addition, because patients with CHD see medical providers more often, they may be less likely to have dementia go undiagnosed.