Infections: asthmatics are particularly hard hit

Larissa Melville completed her traineeship in the editorial team of . After studying biology at Ludwig Maximilians University and the Technical University of Munich, she first got to know digital media online at Focus and then decided to learn medical journalism from scratch.

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Asthma is associated with chronic inflammation of the bronchi. This apparently makes the body more susceptible to infection. Pneumonia, but also urinary tract infections or blood poisoning, occur more frequently in asthmatics.

This is the conclusion reached by the doctor Stig Bojesen and his colleagues from the Faculty of Health and Medicine at the University of Copenhagen. For this purpose, they had collected data from over 105,000 people. At the start of the study, the participants indicated whether they had an atopic disease. This is understood to mean the tendency to have an allergic reaction to substances from the environment. Atopic diseases include, for example, allergic asthma, hay fever or eczema of the skin.

In addition, the researchers asked the study participants whether they smoked regularly or had smoked before. The research team followed the test subjects' medical history for up to 23 years and noted any infectious diseases that required hospitalization.

Infection risk only higher in asthmatics

The analysis of the data showed that even asthmatics who had never smoked had a 44 percent higher risk of serious infections compared to subjects without atopy. The risk of pneumonia was almost doubled. Study participants with other atopic diseases such as dermatitis or hay fever, on the other hand, were no more at risk of infection than the healthy comparison group.

It's not just the lungs that are at risk

In order to avoid confusing asthma with the symptomatically similar chronic obstructive pulmonary disease (COPD), the team analyzed the data of those asthmatics who had been diagnosed before the age of 50 separately again.

The connection between asthma and infections became even clearer: the risk of severe infections was increased by 65 percent for non-smokers. Here too, pneumonia was the most significant: it hit this group of asthmatics almost 2.5 times more often. But the likelihood of infections outside the respiratory tract such as urinary tract infections or blood poisoning rose by 36 percent. The infection rates of the asthmatic smokers were similar.

Suppressed immune system?

What exactly makes asthmatics more susceptible to infection is still unclear. "It is conceivable that the body suppresses the immune system as a reaction to the sometimes life-threatening situations in the context of an asthma disease and thus the defense against infection may be lower," says Bojesen in an interview with This could also explain why atopic eczema and hay fever does not affect the body "There are seldom life-threatening situations and the immune system is consequently less suppressed," says the scientist.

Just as at risk as diabetics

"The risk of a serious infection in non-smoking asthmatics was similar to that of diabetics: 2.2 percent of infection-related hospital admissions were due to asthma, 2.9 percent to diabetes," the researchers write. Asthma could thus be a major risk factor for infections in the general population.

Be careful with the first symptoms

Bojesen advises asthma sufferers to be careful: "If I had asthma, I would not hesitate long and see a doctor at the first possible sign of infection." The researcher also believes that vaccination against influenza and pneumonia is a good idea for this group of people. “Before we can give a definitive vaccination recommendation, however, the effectiveness has to be tested in a study.” One possible limitation is that the protective effect often lasts less in asthmatics than in other people.

Often, but treatable well

An estimated 235 million people worldwide have asthma. The chronic disease of the lungs is accompanied by persistent inflammation and narrowing of the bronchi. The often young patients are tormented by breathlessness, coughing and shortness of breath. But with the right medication for everyday life as well as for acute cases, the disease can now be managed well.

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