Enquête descriptive en milieu scolaire sur la prévalence de l’allergie alimentaire

Prevalence of food allergy and its relationship to asthma and allergic rhinitis in schoolchildren

BACKGROUND

Food allergy (FA) is an important health problem. However, epidemiological studies at the population level are scarce. We assessed the prevalence of FA and its associations with respiratory manifestations among schoolchildren.

METHODS

A total of 6672 schoolchildren aged 9-11 years recruited from 108 randomly chosen schools in six French cities underwent a clinical examination including skin prick test (SPT) to common food and aeroallergens and the standardized protocol of the run test to assess exercise-induced bronchial hyper-responsiveness (EIB). Asthma, allergic rhinitis (AR) and clinical symptoms of FA were determined using a standardized questionnaire completed by parents.

RESULTS

About 2.1% of the children reported symptoms of FA, 1.9% were sensitized to food allergens, and 0.1% had SP-tested FA. The AR was more prevalent than asthma (20.0% lifetime, 11.9% past year vs 9.8%, 8.7% respectively). Reported FA, food sensitization and SP-tested FA were all positively associated with asthma and AR (P < 0.001). These associations persisted also for FA not manifesting as respiratory symptoms (P < 0.001). Asthma and AR remained significantly associated with reported symptoms of FA and allergic sensitization to food allergens after adjustment for confounders as well as for sensitization to aeroallergens. No relationship existed between EIB (9.0%) and FA.

CONCLUSION

The relationships between FA and asthma and AR could be totally explained neither by the existence of respiratory manifestations of FA nor by sensitization to aeroallergens. The FA might intervene differently in asthma and AR.

Oral food challenges in children in Italy

BACKGROUND

Epidemiological surveys identify a 900,000-strong potential paediatric population who may self-report with food allergy in Italy. As the reference test is the double-blind, placebo-controlled food challenge for diagnosis, we carried out a nation-wide questionnaire survey of hospital-based paediatric allergy centres between 1 January and 30 June 2003.

METHODS

All registered centres received a 27-point questionnaire polling logistics and protocols of oral food challenge. Items polled included medical facilities and personnel, selection of patients, foods tested, blinding, placebo use, evaluation criteria, number of tests and positive outcome rates in 2002.

RESULTS

Two hundred and two of 456 responders (44.3%) carried out food challenges (a ratio of one centre to 37,400 children in the general population). 11,728 challenges were performed in 2002 (an average of 58 procedures per centre; range: 1-500) and 3350 procedures were claimed positive (28.6%). Cow's milk was tested by all centres, egg by 77.2%, beef by 19.8% and cereals, peanuts, fish or fruit collectively by 37.6%. Twenty-nine of 202 centres performed blinded tests, 18 of which under double-blinded conditions. In cow's milk challenges, placebos included lyophilized cow's milk capsules, soy formula, extensive whey hydrolysate or extensive casein hydrolysate.

CONCLUSION

Our survey reveals great differences in challenge test criteria, facilities and procedures and that many centres perform relatively few procedures. This argues in favour of greater rationalization in the allocation of tertiary-level resources before procedure standardization can be contemplated in the diagnostic workup of food allergy.