New findings linking common allergies to cardiovascular risks
Key Takeaways
Asthma results in chronic airway inflammation and chronic obstruction, which predisposes patients to atherosclerosis and heart disease.
Preventive measures in atopic patients should target smoking, hypertension, diabetes, and dyslipidemia to decrease the risk of future cardiac disease.
Clinicians should closely follow blood pressure and other cardiac markers in patients with allergies.
The heart and lungs represent continuous organ systems that regulate gas exchange. In addition to their overlapping physiology, the pathophysiology between the organ systems also overlaps. For instance, asthma and atopic dermatitis contribute to heart failure, coronary artery disease, and other forms of cardiovascular disease (CVD).
Allergic disorders
In a population-based study (n=34,417), investigators mined cross-sectional data from the National Health Interview Survey to determine that a history of allergy predicted later hypertension and coronary heart disease.[]
In the study, the allergic group exhibited at least one of the following: asthma, respiratory allergy, digestive allergy, or skin allergy. The researchers found that individuals with a history of allergic disorders who were aged 18–57 years had a higher risk of high blood pressure. Black men aged 39–57 exhibited an increased risk of coronary heart disease. Asthma contributed most to the risk of hypertension and coronary heart disease.
In another population-based study (n=91,692), Danish researchers found that the highest risk of coronary heart disease was observed in patients asthma-COPD overlap with late onset asthma and FEV1 <50%.[] They also found that asthma was correlated with coronary heart disease, but the hazard ratio (HR) was only 1.1 in those with asthma without allergy, compared with an HR of 1.4 in those with asthma and allergy.
Asthma, sleep apnea syndrome, and COPD, have also been associated with the incidence and subsequent death from CVD and its various iterations, as noted by authors writing in Hypertension Research.[]
Furthermore, patients with active asthma are more likely to experience (ischemic) stroke vs those with inactive disease.
Results from the largest asthma and atopic dermatitis genome-wide association study (GWAS) showed a causal relationship between allergic disease and heart failure, with inflammation being a key factor.[] The researchers noted the findings “emphasize the importance of asthma and allergy control in the prevention and management of heart failure.”
Mechanisms
Asthma can be linked to CVD by three possible mechanisms, according to the Hypertension Research authors.
First, chronic airway inflammation secondary to asthma contributes to systemic inflammation, thus resulting in the increased vulnerability of blood vessels to higher coagulability, and the dysfunction of vascular endothelial cells. Taken together, this is a perfect recipe for atherosclerosis.
Second, chronic airway obstruction due to prolonged asthma results in decreased pulmonary function and hypoxemia. Hypoxia may contribute to the pathogenesis of atherosclerosis, in part by the increased secretion of inflammatory mediators.
Third, medications used to treat asthma, including steroids, long-acting β2-agonists (LABAs), or long-acting antimuscarinic antagonists (LAMAs), may contribute to CVD.
Chronic atopic dermatitis also increases the risk of dying of CVD, according to authors publishing in Journal of Atherosclerosis and Thrombosis, with inflammation once again being the tie that binds.[]
“Speculated mechanisms linking chronic dermatitis with CVD include inflammation, which is in part related to impaired skin barrier, platelet dysfunction, and decreased fibrinolysis—all of which can contribute to increased clotting—and treatment for eczema,” wrote one author. “In fact, observational evidence suggests that severe eczema is more clearly associated with an increased risk of CVD, and long-term treatment for chronic eczema by itself appears to increase the risk.”
The activated inflammatory state typical of asthma patients may mediate heart failure via chronic allergic lung inflammation, which causes remodeling of the extra-bronchial lung vasculature that subsequently increases the risk of pulmonary hypertension.
Clinical significance
The relationship between atopy and heart disease is still being investigated, and no evidence-based interventions can yet be recommended. Nevertheless, experts have floated potential preventive interventions based on recent studies.
First, it’s important to appropriately manage asthma—especially in patients with risk factors for CVD. These patients should have their risk factors for CVD systematically assessed and aggressively targeted—including smoking, hypertension, diabetes, and dyslipidemia.
Second, patients with allergic disorders should have their blood pressure routinely evaluated—along with routine examination for coronary heart disease—to ensure early treatment.
What this means for you
Allergy, asthma, and heart disease are overlapping conditions that share inflammatory underpinnings. Patients with allergies should have their blood pressure and other risk factors for coronary heart disease regularly assessed and treated as needed. Importantly, the proper management of asthma may decrease the risk of dying from cardiovascular disease.