Biodiversity Loss May Cause Increase in Allergies and Asthma

Declining biodiversity may be contributing to the rise of asthma, allergies, and other chronic inflammatory diseases among people living in cities worldwide, a Finnish study suggests. Emerging evidence indicates that commensal microbes inhabiting the skin, airway, and gut protect against inflammatory disorders. However, little is known about the environmental determinants of the microbiome.

Ilkka Hanski et al. from the Department of Biosciences, University of Helsinki, investigated whether reduced human contact with nature and biodiversity influences the composition of commensal skin bacteria and allergen sensitivity in a random sample of 118 teenagers living in eastern Finland. The authors found that subjects living on farms or near forests had more diverse bacteria on their skin and lower allergen sensitivity than individuals living in areas with less environmental biodiversity, such as urban areas or near bodies of water.

The findings suggest that the increasing prevalence of inflammatory diseases may be associated with the changing biodiversity of the environment and commensal skin bacteria.

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