Ease up on the cleaning: dust may protect against asthma!

Eradicating dust to prevent childhood asthma may be useless, even counterproductive: the microbiota of certain allergens may have a protective effect.

Asthma, the number one chronic disease in children, may be linked to early exposure to environmental or psychosocial risk factors. The exact nature of these risk factors needs to be determined more specifically in order to devise better prevention strategies.

A group of 442 7-year-olds were examined to identify the causes of their asthma: tobacco use during pregnancy, maternal stress and depression in the first 3 years of life, as well as repeated colds. Sensitivity to an airborne allergen starting at age 2-3 and the mother’s history of childhood asthma were also identified as causes.

Conversely, dust did not systematically appear to be a risk factor. Quite the opposite in fact. Children who lived the first three years of their lives in environments rich in allergens related to the presence of cats, mice, and cockroaches were less at risk than others. A more in-depth analysis of the microbial composition of dust identified bacteria associated with an increased risk of asthma (Staphylococcus, Haemophilus, Corynebacterium and Sphingomonas), and those associated with a reduced risk (Kocuria, Alloiococcus, Bifidobacterium and Acinetobacter).

No need to search for dust in every corner to prevent the development of asthma in a child, the authors conclude; rather, they suggest implementing measures to reduce maternal tobacco use, stress, and depression during pregnancy.


O'Connor GT et al. Early-life home environment and risk of asthma among inner-city children. J Allergy Clin Immunol. 2017 Sep 12. pii: S0091-6749(17)31204-6.