Microbiota in indoor air may protect children from asthma

Large amounts of a certain type of bacteria, most likely from outdoors, may reduce the child's risk of developing asthma.

This was shown by a new study of National Institute for Health and Welfare (THL) that analysed the microbiota in over 400 Finnish homes.

However, the study was unable to identify individual bacterial taxa that provide protection against asthma.

It remains unclear why exposure to microbes protects against asthma.

Earlier studies have found that high diversity of microbes is of particular importance in protecting against asthma. THL’s study, published in June, also showed that farm-like microbiota of the child’s home protected children from asthma also in urban homes.

On average, Finns spend 90% of the time indoors and more and more often in an urban environment.

This means less contact with natural microbiota. The diversity of bacteria protects against asthma but certain soil microbes protect even more effectively.

“In this study, we identified certain groups of bacteria found in soil that protect against asthma. These groups of bacteria provided more effective protection against asthma than the previously observed diversity of microbiota”, said Anne Karvonen, Senior Researcher at THL.

“If we want to develop products that protect against asthma, such as microbes that you can bring home or place on the skin, it would have been helpful to identify individual asthma-protective bacteria. However, our results help to restrict the bacteria that should be studied more.”