Asthma and allergy development: contrasting influences of yeasts and other fungal exposures
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Published on: March 3, 2023
B Behbod1, J E Sordillo, E B Hoffman
1Harvard School of Public Health, Boston, MA, USA.
Background:
Infancy is a developmental stage with heightened susceptibility to environmental influences on the risk of chronic childhood disease. Few birth cohort studies have detailed measures of fungal diversity data in infants' bedrooms, limiting the potential to measure long-term associations of these complex exposures with development of asthma or allergy.
Objective:
We evaluated the relation of home fungal levels in infancy to repeated measures of wheeze and development of asthma and rhinitis by age 13, and sensitization by age 12 years.
Methods:
In the Epidemiology of Home Allergens and Asthma prospective birth cohort study, we recruited 408 children with family history of allergic disease or asthma. When children were aged 2-3 months, we measured culturable fungi in bedroom air and dust, and in outdoor air. Main outcomes included ascertainment of symptoms/disease onset by questionnaire from birth through age 13. We estimated hazard ratios and, for wheeze and sensitization, odds ratios for an interquartile increase in log-transformed fungal concentrations, adjusting for other outcome predictors and potential confounders.
Results:
Elevated levels of yeasts in bedroom floor dust were associated with reduced: i) wheeze at any age; ii) fungal sensitization; and iii) asthma development by age 13 (hazard ratio (HR) = 0.86; 95% confidence interval (CI), [0.75 to 0.98]). Outdoor airborne Cladosporium and dustborne Aspergillus predicted increased rhinitis. Risk of fungal sensitization by age 12, in response to environmental Alternaria and Aspergillus, was elevated in children with a maternal history of fungal sensitization.
Conclusions And Clinical Relevance:
Despite the irritant and allergenic properties of fungi, early-life elevated dust yeast exposures or their components may be protective against allergy and asthma in children at risk for these outcomes. Ascertainment of fungal components associated with immunoprotective effects may have therapeutic relevance for asthma.
Insights
Early-life exposure to yeasts in bedroom dust may protect against childhood asthma and allergies. Higher levels of specific fungi were linked to reduced wheezing and sensitization in at-risk children.
Area of Science:
- Environmental Health
- Pediatric Allergy and Immunology
- Microbiology
Background:
- Infancy is a critical period for environmental exposures influencing chronic childhood disease risk.
- Limited data exists on fungal diversity in infant environments and its long-term health impacts.
- Birth cohort studies are crucial for understanding early-life exposures and disease development.
Purpose of the Study:
- To investigate the relationship between indoor fungal exposures in infancy and the development of wheeze, asthma, and rhinitis by age 13.
- To assess the association of early-life fungal levels with allergic sensitization by age 12.
- To identify specific fungal exposures that may influence the risk of allergic diseases in children.
Main Methods:
- The Epidemiology of Home Allergens and Asthma prospective birth cohort study enrolled 408 high-risk children.
- Culturable fungi were measured in bedroom air, dust, and outdoor air at 2-3 months of age.
- Long-term outcomes (wheeze, asthma, rhinitis, sensitization) were tracked via questionnaires through age 13, with statistical analysis of fungal concentration effects.
Main Results:
- Elevated dust yeast levels were associated with decreased wheeze, fungal sensitization, and asthma development by age 13 (HR=0.86).
- Outdoor Cladosporium and dustborne Aspergillus were linked to increased rhinitis.
- Maternal history of fungal sensitization predicted increased risk of fungal sensitization in children exposed to environmental Alternaria and Aspergillus.
Conclusions:
- Early-life exposure to dust yeasts may offer protection against allergy and asthma in high-risk children.
- Specific fungal components might possess immunoprotective effects relevant for asthma prevention.
- Further research into these protective fungal elements could inform therapeutic strategies for asthma.
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