Congenital heart disease linked to increased risk of dementia
Patients with congenital heart disease (CHD) are more likely to develop dementia, particularly early-onset dementia, as compared with the general population, according to a study from Denmark.
“Although it remains unknown whether the results are directly generalizable to children diagnosed today, they appear relevant for the large population of adults with CHD alive today,” researchers said.
“In the absence of disease-modifying treatments for most dementias, the specific influence of aetiologic factors on CHD is a potential target for future investigations to delay dementia onset in this vulnerable population,” they added.
The Danish population-based cohort study included 10,632 adults (46 percent male) with CHD alive at 30 years of age and 103,403 matched controls. A total of 1,072 developed dementia across both cohorts, with overall dementia incidence rates per 1,000 person-years of 0.78 in the CHD group and 0.75 in the control group. These rates increased with age in both groups. [Circulation 2018;137:1912-1920]
However, the rise in incidence rate of dementia in the CHD population was rather greater than in the general population across all age groups (30–64 years: 0.03 vs 0.01 per 1,000 person-years; 65–79 years: 0.39 vs 0.31 per 1,000 person-years; ≥80 years: 1.93 vs 1.59 per 1,000 person-years).
Cox analysis showed that CHD was associated with a 60-percent increase in the risk of dementia (hazard ratio [HR], 1.61; 95 percent CI, 1.29–2.02). This increase was observed for diagnoses of Alzheimer’s disease, vascular dementia and other dementias, and the HRs did not differ between males and females.
The risk of dementia remained elevated across the entire spectrum of adults with CHD, including those with severe and univentricular disease (HR, 1.96), mild-to-moderate disease complexity (HR, 1.50), with cyanotic potential (HR, 1.83) or acyanotic defects (HR, 1.42), and with or without extracardiac defects (HRs, 7.88 and 1.38, respectively).
Of note, the association between CHD and dementia risk was stronger for early-onset vs late-onset dementia (HR, 2.59; 1.76–3.81 and HR, 1.32; 1.00–1.75).
“Our findings extend the knowledge of long-term neurological impairment and mental health functional morbidities in the population with CHD,” researchers noted, adding that the concept of cerebral reserve provides an explanatory framework for studying the interindividual variation in susceptibility and tolerance of age-related brain changes and pathology.
“CHD is associated with a number of factors that may impact adversely both brain and cognitive reserve, and thus increase the risk of dementia,” they pointed out. Potential aetiologic factors for reducing brain reserve in the population with CHD vary over a lifetime and may involve the following: neurological malformations, the effects of the abnormal physiology, complex medical and surgical management strategies, chromosomal abnormalities, and acquired morbidities.
Having a clear understanding of the risk of adverse long-term neurological outcomes in the growing and ageing population of individuals with CHD is warranted, researchers said.
The study, despite its strengths including a virtually complete follow-up data, had several limitations that could contribute to the underestimation of the true association between CHD and dementia, researchers acknowledged.
“[I]t is important to recognize that the birth period of this cohort (1890–1982) represents an era of more limited opportunities for surgical and medical interventions. Consequently, these results cannot be directly applied to young adults diagnosed with CHD in the present eras,” they warned. “However, it is important to recognize healthcare needs and risk factors affecting the larger number of middle-age and older adults currently living with CHD.”