Faculty of Medicine
Nyhet | Research

Roundworms can cause lower lung-function and asthma in younger males

Exposure to the parasitic roundworm Ascaris lumbricoides among young men can cause a striking reduction in lung function and nearly five times higher odds of having asthma compared to the non-exposed, study shows.

ASCARIS: The roundworm Ascaris lumbricoides appears to be more common in Northern-Europe than previously assumed, the study shows.
Nils Oskar Jõgi

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The findings appear in a new and international study showing how infection with the roundworm parasite Ascarsis lumbricoides affects the lungs. 

Roundworms are a type of intestinal worm that causes infections in humans through contact with parasite eggs. In case of infection, the worm can spread to the lungs which can cause allergy and asthma-like reactions.

In the study, researchers have investigated the presence of Ascaris-infections in Northern Europe (Norway, Denmark and Estonia). 

Not as unusual as assumed? 

The article Ascaris exposure associated with lung function, asthma and DNA methylation in Northern Europe was recently published in The Journal of Allergy and Clinical Immunology. The study is a collaboration between the University of Bergen, the lung clinic at the University of Tartu (Estonia), the University of Aarhus, the University of Birmingham and the University of Cape Town.

Infection with Ascaris is normally considered to be relatively rare in Norway and Northern Europe. However, the researchers have discovered that the presence of this parasite appears to be far more widespread than previously assumed. 

– We show that a large proportion of people in Norway, Denmark and Estonia can be exposed to the worm. When and where the exposure takes place remains a mystery and requires further studies, says PhD-candidae at UiB and first author, Nils Oskar Jõgi.

More serious in young males

A curious finding in the study was that among women, lung function was not significantly lower among the Ascaris-infected. In fact, they appeared to have even less asthma than the rest. This is the first research of its kind to show substantial gender differences in terms of helminth (parasitic worms) exposures and subsequent outcomes in humans. 

The researchers also found that Ascaris infection in Europe might be an overlooked risk factor for asthma and respiratory health.

– Why we see such striking differences is still uncertain, but it could possibly be linked to the different ways men and women fight the infection and the first immune response against the worms, says Jõgi. 

For persons affected, this may result in serious lung damage with the risk of having a long-term impairment of lung function.

The researcher emphasizes that the findings were made in areas where infections with intestinal worms are not widespread. The researchers hope the findings will lead to more research in endemic regions, meaning areas where such infections are more common.

– We believe that this study will increase awareness among the public as well as in academia about a potentially overlooked risk-factor for respiratory health, says Jõgi.