Bronchial responsiveness in atopic adults increases with exposure to cat allergen.
BACKGROUND
The association of asthma with sensitization and allergen exposure is known to be complex. There have been few studies of bronchial responsiveness in relation to both risk factors in adults.


OBJECTIVE
To determine the relation of bronchial responsiveness to allergen exposure and IgE sensitization in a community study taking into account the major determinants of bronchial responsiveness in adulthood.


METHODS
Cross-sectional data were drawn from 1,884 participants in 20 centers in the European Community Respiratory Health Survey follow-up, which included measurement of house dust mite and cat allergen in mattress dust samples, and IgE sensitization to four allergens. Bronchial responsiveness to methacholine was expressed as a continuous variable, and analyzed by multiple regression.


RESULTS
The trend toward greater bronchial responsiveness with increasing exposure to cat allergen was greater in those sensitized to any of the four allergens than those not sensitized (p = 0.001); there was no significant interaction between cat sensitization and Fel d 1 exposure. No trend was found with house dust mite allergen exposure. The difference in bronchial responsiveness between those exposed to the highest levels compared with the lowest was approximately -2.02 doubling doses of PD20 (95% confidence interval, -3.06 to -0.97), and nearly as great in those exposed to more moderate levels.


CONCLUSIONS
Cat allergen exposure at moderate levels may be harmful to all atopic adults. The clinical implication is that it is insufficient to test patients with asthma for cat sensitization; all atopic individuals may benefit from reduced cat exposure.
Chinn
Susan
S
Respiratory Epidemiology and Public Health Group, National Heart and Lung Institute, Imperial College London, London, United Kingdom. s.chinn@imperial.ac.uk
Heinrich
Joachim
J
Antó
Josep M
JM
Janson
Christer
C
Norbäck
Dan
D
Olivieri
Mario
M
Svanes
Cecilie
C
Sunyer
Jordi
J
Verlato
Giuseppe
G
Wjst
Matthias
M
Zock
Jan-Paul
JP
Burney
Peter G
PG
Jarvis
Deborah L
DL
D000328:Adult; D000485:Allergens / Q000276:immunology; D000818:Animals; D039741:Antigens, Dermatophagoides / Q000276:immunology; D060829:Arthropod Proteins; D001249:Asthma / Q000453:epidemiology / Q000276:immunology*; D016535:Bronchial Hyperreactivity / Q000453:epidemiology / Q000276:immunology*; D001985:Bronchial Provocation Tests; D002415:Cats; D003430:Cross-Sectional Studies; D003546:Cysteine Endopeptidases; D004391:Dust; D005060:Europe / Q000453:epidemiology; D005260:Female; D006023:Glycoproteins / Q000276:immunology*; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000453:epidemiology / Q000276:immunology*; D007073:Immunoglobulin E; D008297:Male; D015995:Prevalence; D039981:Pyroglyphidae / Q000276:immunology*; D012737:Sex Factors
D000485:Allergens; D039741:Antigens, Dermatophagoides; D060829:Arthropod Proteins; D004391:Dust; D006023:Glycoproteins; D007073:Immunoglobulin E; D003546:Cysteine Endopeptidases; C451159:Dermatophagoides farinae antigen f 1; C059296:Fel d 1 protein, Felis domesticus