Protective Factors for the Development of Childhood Asthma and Allergies Encountered in Rural Environments

Protective factors for the development of childhood asthma and allergies in rural environments Prof. Dr. med Charlotte Braun-Fahrländer Swiss Tropical and Public Health Institute, Basel, Switzerland GRF One Health Summit 2012, Davos Plenary III: Priorities for Health regarding Chronic Respiratory Diseases

Background
Childhood asthma leading paediatric chronic disease in industrialized countries
Strong increase in asthma and allergic diseases in high-income countries over past decades
Increase in populations undergoing transition from traditional to ‘modern’ lifestyle
Global health problem resulting in massive social and economic cost to community
No effective primary prevention

Which factors explain the geographic and temporal differences in asthma and atopy prevalence?
Increase in risk factor exposure
ETS
traffic exposure
indoor combustion
Allergen exposure
Dietary habits
Childhood obesity
Increase in disease susceptibility due to a loss of protective factors (‘Hygiene-Hypothesis’)?
Less exposure to infections
Changes in environmental microbial exposure

Braun-Fahrländer et. al. 1999 The persons who are most subjected to the action of pollen belong to a class which furnishes the fewest cases of hay fever, namely, the farming class‘. Charles Blackley 1873 Reported in more than 30 studies in various countries v. Mutius, Nature Rev Immunol 2010 School children living on a traditional farm suffer less from asthma and allergies than their peers living in the same village

Farm Exposure in the 1. year of life and asthma/ allergy at school age (ALEX study) % Riedler et al. Lancet 2001; 358:1129-1133

Microbial exposures Bacteria, Fungi Allergens Grass pollen, cow epithelia, mites Plant derived material polysaccarides (arabinogalactans) Typical exposures And many others….

Diversity of environmental microbial exposure of indoor dust sample is inversely related to asthma Ege et al. NEJM 2011 Farm child Bacteria (PARSIFAL study) Farm child Fungi (GABRIELA study) Farm child Asthma Asthma

Unprocessed farm milk consumption independently related to asthma and allergies Waser CEA 2007

p<0.0001 p<0.0001 p = 0.0342 Ege, Bieli JACI 2006 TLR2 TLR4 CD14 Genexpression of innate immunity receptors of farm and non-farm children (PARSIFAL)

Working model of Immunobiology of farm exposure (Vercelli D, von Mutius E, Nature Reviews Immunology 2010)

‘ Farm model’: a one health approach
Farming environment = inter e sting model to study the role of microbial exposure on asthma and atopy development in Westernized countries
Large gradients in exposure to a variety microbes/ compounds in children with otherwise comparable (Western) lifestyle (air pollution, access to medical care, housing conditions etc).
Exposure situation and gradients may be very different in non-affluent countries
Hygiene hypothesis not complete explanation of increase in atopic diseases in westernized countries
One health approach offers better understanding of protective factors and may provide opportunities for prevention

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Protective Factors for the Development of Childhood Asthma and Allergies Encountered in Rural Environments

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Protective Factors for the Development of Childhood Asthma and Allergies Encountered in Rural Environments Presentation Transcript