Have you ever wondered if being born with a heart defect could raise the odds of later developing dementia, especially early-onset dementia?
It is estimated that about fifty million (50) people worldwide have dementia. For instance, in the United States, Alzheimer’s disease is recognized as the most common form of dementia in older adults, affecting 5.5 million Americans and it has been ranked as the nation’s No. 6 cause of death.
Advances in the field of medicine, molecular biology and genetics have allowed more children with congenital heart disease to survive to adulthood. However, a number of congenital heart defects have been linked to the development of one or more disorders in later stages of life. For instance, congenital heart disease has been shown to be associated with the risk factor for dementia.
In a cohort study involving the use of medical registries and a medical record review covering of all Danish hospitals aimed to identify adults with congenital heart disease diagnosed between 1963 and 2012, it was discovered that the overall incidence of dementia was four percent (4%) by eighty (80) years of age in a population of 10 632 adults with CHD (46% male). This represents a 60 percent higher risk than what was seen in the general population. Furthermore, those born with a heart defect were also 2.6 times more likely to develop dementia before age 65. That is, congenital heart disease was associated with an increased risk of dementia compared with the general population, in particular for early-onset dementia.
A number of hypothesis including brain injury has been suggested for the relationship between congenital heart disease and dementia. This is because brain injury is common in individuals with congenital heart disease. Mebius et al., (2017) have shown the influence of brain injury in individuals with congenital heart disease. The authors proved that up to 52 percent of individuals with congenital heart disease show signs of brain injury on MRI (Magnetic Resonance Imaging) before surgery and this increases up to 78 percent after surgical operation. Although the etiology of brain injury in individuals living with congenital heart disease is multifactorial, but the disruption of genetic pathways appears to be a prominent reason for the development of brain injury in the later stages of life of individuals living with congenital heart disease.
Hence, individuals living with congenital abnormality are susceptible to disruption of developmental pathways, that is, organogenesis of both organs (that is the heart and the brain).
Another factor that has been suggested for the development of brain injury, which might lead to dementia, in individuals with congenital heart defects is mutation. Mutations in the genes of identical origin that are expressed in both the heart and the brain have been suggested as a reason behind the development of brain injury in people living with congenital heart disease (Homsy J et al., 2015)
It is hoped that this finding will help in the accurate diagnosis of dementia and the effective management of dementia.