(Madrid, 11 October 1999) Regular contact during childhood with farm animals could provide lasting protection against allergic illnesses, according to the authors of a broad-ranging study conducted in Austria on 2283 children aged between 8 and 10. The study, which was presented on Monday at the meeting of the European Respiratory Society (ERS) in Madrid, was a joint effort, by the Paediatric Pulmonology Department of the children's hospital and the Public Health Department of the city of Salzburg, under the responsibility of Dr Josef Riedler.
The parents of the children were asked in a detailed questionnaire to provide information about the children's daily lives and about any allergies they were suffering from. At the same time, 1137 of the children were subjected to what the doctors call "skin prick tests", which were intended to show up any immediate hyper-sensitivity to 7 different substances that could cause local allergies.
When the data were sifted through, it turned out that the children living on farms were 3 times less sensitive to hay fever than those living in a non-rural environment (3.1% compared with 10.3%). In the case of asthma, the ratio was even more pronounced: 1.1% compared with 3.9%. Reactions to skin prick tests were about twice less frequent (18.8% against 32.7%) for farm children as for the others.
This clearly marked difference persisted when other factors were taken into account, such as genetic background, parents' education, eating habits and living conditions.
In order to make quite sure and to refine his results, Josef Riedler tested how the figures would look in the case of regular contact with cattle or poultry, regardless of the kind of environment the child lived in. The gap between town and country in fact closed substantially, highlighting rather the decisive influence of regular contact with farm animals.
The reason why some children develop protection has not been established, although-as the Austrian doctor explained in Madrid-- "a possible explanation might be the development of immune tolerance or the stimulation of Th1 cells and suppression of Th2 cells, by increased exposure to microbial antigens in the stables or farm houses."
But beware of rushing to conclusions, warns Prof. Kai-Håkon Carlsen, Head of the ERS Pediatric Assembly and Director General of the Voksentoppen National Hospital in Oslo: "Previous studies have shown that early allergen contact (during the first year of life) may predispose to allergy later in life. This has been reported for pollen and for animal dander. In the light of the present report, it is therefore important to establish whether there are bacterial products or antigens from stables that may be effective in protecting against later sensitisation for children raised on farms. It should not be forgotten that for children who have developed an allergy towards domestic animals like cats or dogs, it is very important to keep them away from those animals in order to counteract a more severe development of the disease."
Contact:
Dr Josef Riedler
Dept of Paediatric Pulmonology, Children's Hospital, Salzburg
Tel: (+43 662) 4482 2601
Fax: (+43 662) 4482 2604
e-mail: j.riedler@lkasbg.gv.at
Note to Editors: please do not forget to mention that this study has been presented at the Madrid ERS annual meeting.
This release was written by Eric Schaerlig, Igor Chlebny and Peter Whiting, Cedos International, Carouge-Geneva, Switzerland