[European birth cohorts: Early life exposure to microorganisms and health impact]

Area of Science:

• Environmental microbiology
• Pediatric allergy
• Epidemiology

Background:

• Numerous European birth cohorts have been established to study early life microbial exposures in indoor environments.
• Understanding these exposures is crucial for identifying protective or adverse health effects in children.
• Existing research varies in methodology for exposure assessment and allergy risk evaluation.

Purpose of the Study:

• To review and synthesize findings from 12 European birth cohorts on indoor microbiological exposure.
• To present results from four meta-analyses of these cohorts.
• To highlight the need for standardized metrological approaches in microbial exposure research.

Main Methods:

• Review of data from 12 European birth cohorts.
• Inclusion of four meta-analyses of cohort studies.
• Analysis of methodologies for microbiological exposure and allergic risk assessment.

Main Results:

• Significant variation exists in the methodologies used across European birth cohorts.
• Few studies provide quantitative microbiological data, hindering dose-effect relationship establishment.
• A global view requires identical metrological approaches across large-scale, well-defined birth cohort studies.

Conclusions:

• Standardized, quantitative metrological approaches are essential for understanding dose-effect relationships between indoor microbial exposure and child health.
• Large-scale birth cohorts with strict diagnostic criteria are vital for robust allergy risk assessment.
• Future research should focus on harmonizing methods to enable meaningful comparisons and reliable conclusions.