Cardiovascular Abnormalities in Children With Attention-deficit/Hyperactivity Disorder

Introduction

ADHD is a common and highly heritable neurodevelopmental disorder with an estimated worldwide prevalence of 3-7% in childhood and adolescence, and around 3% in adulthood . The prevalence of ADHD in the Middle East and North Africa region is estimated at approximately 10.3% among children, adolescents, and adults. The estimated prevalence was 12% in Egypt .

ADHD is characterized by developmentally inappropriate, pervasive and impairing inattention and/or hyperactivity-impulsivity. In addition to the core clinical symptoms of ADHD, co-occurring poor mental and physical comorbidities are prevalent in individuals with ADHD. However, compared with the extensive research of psychiatric comorbidities in ADHD, physical comorbidities, such as cardiovascular diseases , have received less attention, particularly among adults .

ADHD has a multifactorial etiology; however, its prevalence appears significantly higher in children with congestive heart disease, particularly those undergoing complex cardiac procedures such as aortic arch repair or correction of transposition of the great arteries . Children and adolescents with ADHD have a higher risk for cardiovascular disease. Common carotid intima media thickness , epicardial adipose tissue thickness , and periaortic adipose tissue thickness were higher in children and adolescents with ADHD, and therefore they were at risk for CVD .

A recent genetic study revealed weak-to-moderate genetic correlations of ADHD with BMI, coronary artery disease and levels of triglycerides and HDL cholesterol.

There are several reasons why individuals with ADHD could be at increased risk for CVDs. First, previous research suggests that the link between ADHD and CVDs is biologically plausible via immune system abnormalities, neuromodulator dysregulation, and dysregulation of the hypothalamic-pituitary-adrenal axis . Second, individuals with ADHD are at increased risk for unhealthy lifestyle factors (e.g., obesity, poor physical activity) which are all well-established risk factors for CVDs . Third, previous studies indicate that several psychiatric comorbidities of ADHD, for example, depression, substance use disorders, bipolar disorder, are associated with CVDs . Fourth, even though findings are inconclusive, there has been a long-standing concern around a potential increased risk of cardiovascular events due to the use of stimulant medications to treat ADHD. Most ADHD treatments are known to elevate heart rate and blood pressure through stimulation of the sympathetic nervous system, thus potentially conferring a risk of cardiovascular side-effects. Acute coronary syndromes, stroke, and heart failure have all been linked with treatment in some reports. However, the available epidemiological findings are mixed, despite the potential hypotheses for an increased risk of CVDs in ADHD.