Pets keeping in home, parental atopy, asthma, and asthma-related symptoms.

Pets keeping in home, parental atopy, asthma, and asthma-related symptoms.
The study named “Pets keeping in home, parental atopy, asthma, and asthma-related symptoms in 12910 elementary school children from northeast China” was conducted in 2008 by G.-H. Dong, Y.-N. Ma, H.-L. Ding, J. Jin, Y. Cao, Y.-D. Zhao and Q.C. He (further referred as Dong et al.). This study was meant to analyze the relationship between allergic respiratory diseases in childhood and such factors as pet keeping (both at home and outside) and parental atopy, as well as the interaction of these factors. The results of the study show that presence of animals increases risk of children’s respiratory diseases and hereditary atopy increases this risk.

The introduction section discusses previous research on the topic. Previous findings are ambiguous: some researcher state that pet presence during the infancy leads to lower asthma reactivity and overall sensitization for children; other studies have not discovered this protective effect. Apelberg (2001) showed that pet exposure increases risk of asthma for children younger than 6 y.o., but does not have such effect for older children. Also, it has been found that consequences of pet presence for children’s health differ in different parts of the world. Sensitivity to allergens and respiratory diseases also differs: researchers have proved that in China prevalence of asthma is lower than in western countries. Basing on this fact, Dong et al. found it useful to conduct a study for Chinese children concerning per exposure effect on respiratory diseases.

Introduction section also contains the area of study of current research: the relation between self-reported pet exposure and such issues as doctor-diagnosed asthma and asthma-related symptoms. Distinct feature of the considered paper is that results of analysis were considered with regard to hereditary allergic diseases, and thus has excluded potential confounders that were present in previous studies.

Methods section contains the description of subjects of research, questionnaire used, definitions of symptoms and illnesses considered in the research and statistical analysis methods.

Subjects of study were planned to be 13778 elementary school pupils, from 7 to 13 years old, residing in Liaoning province. Twelve cities were randomly selected (from three cities), and from each district one school was randomly selected. Teachers explained the essence of the survey to parents (it was presented as a study on environmental factors in general, in order to avoid bias). Parents filled in the survey at home. Questions in the survey were taken from American Thorasic Society Epidemiologic Standardization Project questionannire, and contained, in addition to measuring basic variables, factors related to pet keeping (and identification) and parental atopy.

Statistically, the connection between doctor-diagnosed asthma (or asthma-related symptoms) and parental atopy as well as between the former factor and pet exposure. Independent and joint effects of these factor were also studied.

The results section shows the effects of studied variables on respiratory diseases. Parental atopy appeared to have a strong correlation with asthma and related symptoms; pet exposure during pregnancy and during first years of life also correlated with prevalent asthma and asthma-related symptoms. Though type of animals did not play an important role in the relation, it appeared that current asthma is strongly related with exposure to farm animals.

It was statistically proved that parental atopy alone also increases the risk of respiratory diseases, especially doctor-diagnosed asthma. The study also revealed an interaction effect of the two main factors: parental atopy and pets exposure. For example, excess risk of persistent phlegm was 67% for children with parental atopy only, 95% for children with pet exposure only, and 341% for children with both factors present.

The discussion section contains the consideration of potential confounders and other variables that might influence development of respiratory diseases for children. Current study has shown that when elementary school children are exposed to pets, it increases the possibility of respiratory diseases. Protective effect of pet exposure during the first years of life mentioned in previous research is discussed, and possible reasons for this effect are considered. E.g. high exposure to microbial products during infancy may be the cause of this effect; differences of western and eastern population’s exposure to microbial products are discussed, and such phenomenon as “healthy pet keeping effect” is considered. The issues of keeping pets indoors and outdoors and different levels of respiratory diseases for elementary school children are mentioned. Differences between urban and rural environment are discusses, and it is underlined that the focus of this study is on rural children; thus, this study proves that keeping pets increases the risk of respiratory diseases for rural children. Hereditary issues concerning respiratory diseases are also considered in the discussion section.

Concluding part of the paper states summary of the results: the correlation exists between self-exposure to pets and asthma symptoms for Chinese children; association of pet keeping and asthma (doctor-diagnosed and symptoms of asthma) were stronger for children without parental atopy. For cases of children’s persistent phlegm effect of parental atopy was witnessed.

Pets keeping in home, parental atopy, asthma, and asthma-related symptoms. 7.8 of 10 on the basis of 1976 Review.