Background Western lifestyle is associated with high prevalence of allergy, asthma and
other chronic inflammatory disorders. To explain this association, we tested the 'biodiversity
hypothesis', which posits that reduced contact of children with environmental biodiversity,
including environmental microbiota in natural habitats, has adverse consequences on the
assembly of human commensal microbiota and its contribution to immune tolerance.
Methods We analysed four study cohorts from Finland and Estonia (n= 1044) comprising …

METHODS. Home inspection by a trained civil engineer, including assessment of moisture
damage and mold, was undertaken when the child was 5 months of age and children were
followed to 6 years of age. There were periodic evaluations of the child, including allergy
testing at age 6 years. RESULTS. Signs of moisture damage with or without mold at an early
age in the child's main living areas were associated with having physician diagnosed
asthma “ever,” persistent asthma, and respiratory symptoms during the first 6 years of life …