A new study has suggested that adults with persistent asthma may be at an increased risk of stroke.
This increased risk is caused by a buildup of excess plaque in the carotid arteries and higher levels of inflammation.
Individuals involved in the study had more plaque buildup in the carotid arteries, large arteries on the left and right side of the neck that carry blood to the brain, compared to those without asthma.
Asthma and inflammation
Asthma is a respiratory condition that causes an individuals airways to become inflamed, often due to allergic reactions, which makes it hard for that individual to breathe.
Over time, chronic inflammation is known to contribute to artery plaque buildup called atherosclerosis.
Atherosclerosis is associated with a higher risk of plaques rupturing, which can trigger a stroke.
Lack of awareness
Lead study author, Matthew C. Tattersall, says: “Many physicians and patients don’t realise that asthmatic airway inflammation may affect the arteries, so for people with persistent asthma, addressing risk factors for cardiovascular disease may be really helpful.
“The presence and burden of carotid artery plaque is a strong predictor of future cardiovascular events.”
Analysis
For this study, the researchers used data from participants enrolled in the Multi-Ethnic Study of Athersclerosis (MESA) study in order to examine the potential ties between asthma and carotid artery plaque.
MESA is a recent study of over 7,000 adults which began in 2000 and is still currently following participants across six locations across the United States: Chicago, New York, Los Angeles, North Carolina, Minnesota and Baltimore.
At time of enrolment, all participants in the MESA study were free from cardiovascular disease.
The researchers reviewed health data for 5,029 adults, average age of 61, who had baseline risk factors for cardiovascular disease and for whom there was carotid ultrasound data.
The participant group is diverse: 26 per cent of adults self-identified as African American, 23 per cent self-identified as Hispanic and 12 per cent self-identified as Chinese, 53 per cent of the group was also female.
The participants in this analysis’s cohort were categorised as having persistent asthma, intermittent asthma or not having asthma.
. The subgroup with persistent asthma, defined as using daily controller medications to control asthma symptoms, connoted of 109 participants.
. Those in the intermittent asthma group, defined as having history of asthma but not using daily medications to control asthma symptoms, consisted of 388 participants.
At the beginning of the MESA study, all participants had an ultrasound of the left and right carotid arteries to identify any carotid artery plaque.
The total plaque score defined the number of plaques in the walls of both carotid arteries.
Blood levels of inflammatory biomarkers interleukin-6 (IL-6) and C-reactive protein (CRP) were also measured at the start of the MESA study.
Findings & Conclusion
- Carotid plaque was present in 67% of participants with persistent asthma and 49.5% of those with intermittent asthma. Those with persistent asthma had an average of two carotid plaques, and those with intermittent asthma about one carotid plaque.
- Carotid plaque was present in 50.5% of the participants without asthma, with an average of about one carotid plaque.
- After adjusting for age, sex, race, weight, other health conditions, prescription medication use and smoking, participants with persistent asthma had nearly twice as high odds of having plaque in their carotid arteries than those without asthma.
When compared to participants without asthma, individuals with persistent asthma had higher levels of inflammatory biomarkers. (Individuals with persistent asthma had an average IL-6 level of 1.89 pg/mL, while those free from asthma had an average IL-6 level of 1.52 pg/mL.)
The researchers also found that accounting for IL-6 and CRP in the fully adjusted analysis did not reduce the association between persistent asthma and carotid asthma.
Tattersall says: “The most important message from our findings is that more significant forms of asthma are associated with more cardiovascular disease and cardiovascular events.
“Addressing cardiovascular risk factors through lifestyle and behaviour adjustments can be a powerful preventive tool for patients with more severe forms of asthma.”
