Pets, parental atopy, and asthma in adults.
BACKGROUND
Studies of exposure to pets and the risk of asthma have provided conflicting results.


OBJECTIVE
We conducted a population-based incident case-control study to assess the relationship of current and previous pet keeping with the risk of adult-onset asthma. We also investigated whether genetic propensity as a result of parental atopy modifies these relations.


METHODS
From the source population of 441,000 inhabitants of a geographically defined area in South Finland, we systematically recruited, during a 2.5-year period, all new cases of asthma in 21- to 63-year-old adults and randomly selected control subjects. The clinically diagnosed case series consisted of 521 adults with newly diagnosed asthma and a control series of 932 control subjects. Information on current and past exposure to hairy pets was collected by using a self-administered questionnaire.


RESULTS
In logistic regression analysis the risk of asthma was lower among subjects with pets during the past 12 months (adjusted odds ratio [OR], 0.74; 95% confidence interval [CI], 0.57-0.96) but higher among subjects with pets more than 12 months previously (adjusted OR, 1.39; 95% CI, 1.05-1.84). Parental atopy increased the risk of asthma (OR, 1.88; 95% CI, 1.47-2.41), but there was no interaction between parental atopy and pet exposure.


CONCLUSIONS
The present results are consistent with the hypothesis that both keeping furry pets and parental atopy increase the risk of asthma development in adulthood. Parental atopy does not modify the effects of pet exposure. The negative association between current pets and the risk of asthma is consistent with selective avoidance of these pets by symptomatic individuals.
Jaakkola
Jouni J K
JJ
Environmental Health Program, The Nordic School of Public Health, Göteborg, Sweden.
Jaakkola
Niina
N
Piipari
Ritva
R
Jaakkola
Maritta S
MS
D000328:Adult; D000818:Animals; D000829:Animals, Domestic / Q000276:immunology*; D001249:Asthma / Q000209:etiology*; D016022:Case-Control Studies; D004781:Environmental Exposure; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D006967:Hypersensitivity / Q000150:complications / Q000235:genetics* / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010290:Parents; D012016:Reference Values; D018570:Risk Assessment