A recent study found that people with persistent asthma had higher levels of inflammation and more artery plaque than those without asthma, suggesting they ran a higher risk of heart attack or stroke, and highlighting the need for managing heart disease risk factors in these individuals.
Asthma affects an estimated 262m people worldwide, with previous research linking it to atherosclerosis – the build-up of plaque, or fatty deposits, on artery walls. Still, the associations between asthma and heart disease are unclear.
Yet a 2020 study found that people with persistent asthma may have up to 1.5 times higher risk of developing atrial fibrillation (AFib) than those without the respiratory condition, reports Medical News Today.
The latest study found that participants with persistent asthma have a greater likelihood of plaque buildup in their carotid arteries than those without asthma, even after the scientists adjusted for demographic and lifestyle factors. Moreover, those with persistent asthma also had higher levels of inflammatory markers in their blood.
The study was published in the Journal of the American Heart Association.
Linking asthma and atherosclerosis
To investigate their hypothesis, the scientists collected data from participants in the Multi-Ethnic Study of Atherosclerosis (MESA) study. The MESA study includes a large, ethnically diverse cohort of 6 814 adults who did not have cardiovascular disease at the time of enrolment.
The research team examined the data from 5 029 adults in the MESA who had cardiovascular disease risk factors and carotid ultrasound data in their records.
At the start of the MESA study, participants also had blood levels of interleukin-6 (IL-6) and C-reactive protein (CRP) measurements taken. IL-6 and CRP are inflammatory markers in the blood.
The scientists divided the participants into either persistent asthma, intermittent asthma, or no asthma groups: they defined persistent asthma as asthma requiring daily use of controlling medications. Participants in the intermittent group had a history of asthma but did not use controlling medications daily.
Among the participants, 109 had persistent asthma, 388 had intermittent asthma, and the remaining 4 532 did not have the condition.
Carotid plaques and inflammatory markers
After analysing the data, the researchers discovered several key findings. Specifically, 67% of participants with persistent asthma had an average of two plaques in their carotid arteries. In contrast, 49.5% of people with intermittent asthma and 50.5% without asthma had about one carotid plaque.
After the scientists adjusted the data for factors including prescription medication use, age, race, sex, other health conditions, and smoking, they found that individuals with persistent asthma had a significantly higher risk of having plaque in their carotid arteries than those who did not have asthma.
Additionally, inflammatory markers in the blood were slightly higher in participants with persistent asthma.
For example, IL-6 measurements in the persistent asthma group averaged 1.89 pg/mL. In contrast, those who did not have asthma had average IL-6 measurements of 1.52 pg/mL.
Moreover, CRP measurements averaged 6.49 mg/L in the persistent asthma group and 3.61 mg/L in participants without asthma.
However, accounting for the inflammatory biomarkers did not lessen the association between persistent asthma and carotid artery plaque.
More research on asthma and atherosclerosis still needed
Lead study author Matthew Tattersall, DO, MS, an assistant professor in the department of medicine at the University of Wisconsin, Madison, said: “This analysis tells us that the increased risk for carotid plaques among people with persistent asthma is probably affected by multiple factors. Participants who have persistent asthma had elevated levels of inflammation in their blood, even though their asthma was treated with medication, which highlights the inflammatory features of asthma. We know that higher levels of inflammation lead to negative effects on the cardiovascular system.”
According to the study authors, the discovery underscores the need for more research into the shared mechanisms of atherosclerotic cardiovascular disease (ASCVD) and asthma.
After reviewing the research, Dr Russell Luepker, MS, heart health and cardiovascular epidemiology and prevention expert and professor emeritus at the Division of Epidemiology and Community Health, University of Minnesota, agreed that more investigations are needed.
He told Medical News Today that the study does not imply causation as recognised by the authors. He said the following questions cannot be answered: Does severe asthma cause carotid disease? Does carotid disease cause asthma?
“(The research team) hoped that biomarkers for inflammation (CRP, IL-6) would provide evidence for a connection, but they did not, leading to the conclusion that this was multifactor with the other factors unknown. Other than the association with severe asthma, the relationships are modest.”
Study details
Persistent Asthma Is Associated With Carotid Plaque in MESA
Matthew Tattersall, Alison Dasiewicz, Robyn McClelland, Nizar Jarjour, Claudia Korcarz, Carol Mitchell, Stephane Esnault, Moyses Szklo and James Stein
Published in the Journal of the American Heart Association on 23 November 2022
Abstract
Background
Asthma and atherosclerotic cardiovascular disease share an underlying inflammatory pathophysiology. We hypothesised that persistent asthma is associated with carotid plaque burden, a strong predictor of atherosclerotic cardiovascular disease events.
Methods and Results
The MESA (Multi‐Ethnic Study of Atherosclerosis) enrolled adults free of known atherosclerotic cardiovascular disease at baseline. Subtype of asthma was determined at examination 1. Persistent asthma was defined as asthma requiring use of controller medications, and intermittent asthma was defined as asthma without controller medications. B‐mode carotid ultrasound was performed to detect carotid plaques (total plaque score [TPS], range 0–12). Multivariable regression modeling with robust variances evaluated the association of asthma subtype and carotid plaque burden. The 5029 participants were a mean (SD) age of 61.6 (10.0) years (53% were women, 26% were Black individuals, 23% were Hispanic individuals, and 12% were Chinese individuals). Carotid plaque was present in 50.5% of participants without asthma (TPS, 1.29 [1.80]), 49.5% of participants with intermittent asthma (TPS, 1.25 [1.76]), and 67% of participants with persistent asthma (TPS, 2.08 [2.35]) (P≤0.003). Participants with persistent asthma had higher interleukin‐6 (1.89 [1.61] pg/mL) than participants without asthma (1.52 [1.21] pg/mL; P=0.02). In fully adjusted models, persistent asthma was associated with carotid plaque presence (odds ratio, 1.83 [95% confidence interval, 1.21–2.76]; P<0.001) and TPS (β=0.66; P<0.01), without attenuation after adjustment for baseline interleukin‐6 (P=0.02) or CRP (C‐reactive protein) (P=0.01).
Conclusions
Participants with persistent asthma had higher carotid plaque burden and higher levels of inflammatory biomarkers, compared with participants without asthma. Adjustment for baseline inflammatory biomarkers did not attenuate the association between carotid plaque and asthma subtype, highlighting the increased atherosclerotic cardiovascular disease risk among those with persistent asthma may be multifactorial.
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