Pet Avoidance Research Articles

Home Exposures, Parental Atopy, and Occurrence of Asthma Symptoms in Adulthood in Southern Taiwan

Parental atopy and environmental exposures at home have been recognized risk factors for adulthood asthma. However, the relative contributions of specific risk factors and the overall contributions of heredity or home exposure remain unexplored. The purpose of this study was to identify predictors and estimate the population attributable risk (PAR) of each exposure for typical asthma symptoms among 26- to 50-year-old Taiwanese. We also investigated whether an interactive effect existed between parental atopy and home exposures on the occurrence of asthma symptoms in adulthood. A cross-sectional study with retrospective components. Elementary and middle schools in Southern Taiwan. Between March and October 2004, we conducted a cross-sectional survey among schoolchildren's parents from 94 elementary and middle schools in Southern Taiwan. The main outcome measure was typical asthma-like symptoms occurring within the preceding 5 years. Information on hereditary and home exposures was collected by using a self-administered questionnaire. After excluding unqualified questionnaires, data from 24,784 subjects were left for analysis. New-onset asthma was reported for 0.83% of male (n = 80 of 9,662) and 1.36% of female subjects (n = 206 of 15,122). Besides parental atopic factors, environmental tobacco smoke or pet avoidance and visible mold on walls at home were independently associated with the occurrence of asthma symptoms. Mutually adjusted models produced statistically significant associations between any home exposure (odds ratio [OR], 1.80; 95% confidence interval [CI], 1.08 to 3.23; PAR, 28.04%), parental atopy (OR, 4.47; 95% CI, 3.47 to 5.75; PAR, 31.38%), and new-onset asthma. However, there was no interaction between parental atopy and home exposures. Home exposures and parental atopy both increased the risks of new-onset asthma in adulthood but did not show an interactive effect. These two exposure categories approximately contributed equally to the adulthood asthma.

The Canadian Childhood Asthma Primary Prevention Study: Outcomes at 7 years of age

Avoidance of any one of the individual risk factors associated with childhood asthma has not been successful in preventing its development. The purpose of this study is to determine the effectiveness of a multifaceted intervention program for the primary prevention of asthma in high-risk infants at 7 years of age. Five hundred forty-five high-risk infants with an immediate family history of asthma and allergies were prospectively randomized into intervention or control groups prenatally. Intervention measures introduced before birth and during the first year of life included avoidance of house dust, pets, and environmental tobacco smoke and encouragement of breast-feeding with delayed introduction of solid foods. Assessment of outcomes at 7 years consisted of examination by pediatric allergists, methacholine inhalation tests, and allergy skin tests. At 7 years, 469 of the 545 children were contacted, and 380 returned for further assessment. The prevalence of pediatric allergist-diagnosed asthma was significantly lower in the intervention group than in the control group (14.9% vs 23.0%; adjusted risk ratio, 0.44; 95% CI, 0.25-0.79). The prevalence of allergic rhinitis, atopic dermatitis, atopy (defined as positive skin test reactions to any common allergen), and bronchial hyperresponsiveness (defined as the provocative concentration of methacholine that induced a 20% decrease in FEV 1 from a postsaline value of less than 7.8 mg/mL) were not significantly different between the 2 groups. The prevalence of asthma (defined as wheeze without colds and the presence of bronchial hyperresponsiveness) was also significantly lower in the intervention group compared with the control group (12.9% vs 25.0%; adjusted risk ratio, 0.39; 95% CI, 0.22-0.71). The multifaceted intervention program was effective in reducing the prevalence of asthma in high-risk children at 7 years of age.

Exposure to pets, and the association with hay fever, asthma, and atopic sensitization in rural children

An increasing number of studies report pet exposure to be associated with lower risk of asthma and allergies. This 'protective pet effect' has been suggested to result from a modified T-helper (Th)2-cell response, or because of increased microbial load in homes where pets are kept. We examined the associations between pet contact and the occurrence of asthma and allergies in children of the rural Allergy and Endotoxin (ALEX) population, taking farm animal contact, endotoxin and cat allergen levels in mattress dust into account. Information about contact with pets and farm animals, asthma and allergy were collected for 812 children by a standardized parents' questionnaire and an interview. Mattress dust endotoxin and cat allergen levels as well as specific IgE and IgG4 antibodies to Fel d1 were determined. Current contact with dogs was inversely associated with diagnosed hay fever (OR 0.26, 95% CI 0.11-0.57), diagnosed asthma (OR 0.29, 95% CI 0.12-0.71), sensitization to cat allergen (OR 0.48, 95% CI 0.23-0.99) and to grass pollen (OR 0.55, 95% CI 0.33-0.94), but not with increased IgG4 levels. Early and current contact with cats were associated with reduced risk of wheezing (OR 0.48, 95% CI 0.23-1.00, and OR 0.49, 95% CI 0.26-0.92, respectively) and grass pollen sensitization. Adjustment for farm animal contact but not for endotoxin and cat allergen exposure attenuated these associations and the effect of pet was stronger among farmers' children. Although pet exposure was very frequent in this rural population, the inverse relation between current dog contact, asthma and allergy was mostly explained by simultaneously occurring exposure to stable animals or was restricted to farm children. In addition, a subtle form of pet avoidance may contribute to the protective effect of pet.

FOUR-YEAR INCIDENCE OF ALLERGIC SENSITIZATION AMONG SCHOOLCHILDREN IN A COMMUNITY WHERE ALLERGY TO CAT AND DOG DOMINATES SENSITIZATION: REPORT FROM THE OBSTRUCTIVE LUNG DISEASE IN NORTHERN SWEDEN STUDY GROUP

Ronmark E, Perzanowski M, Platts-Mills TAE, Lundback B. J Allergy Clin Immunol. 2003;112:747–754To evaluate the incidence of type 1 sensitization during a 4-year period among schoolchildren in northern Sweden (a dust mite- and cockroach-free environment) and to examine the risk factors for sensitization, including cat and dog ownership.A total of 1870 schoolchildren, 7 to 8 years of age at the beginning of the study, were derived from a longitudinal cohort of 2454 children living in 2 municipalities in northern Sweden in 1996.Skin prick tests for tree, grass, weed, dust mite, mold, cat, dog, and horse allergens were conducted. The same children were retested 4 years later. A positive reaction was recorded if the wheal was ≥3 mm after 15 minutes. The participation rate was 88% during both collection periods. CAP system immunoglobulin E antibodies to cat, dog, tree, and grass allergens were determined in sera collected from 923 children during the second data collection period. A parental questionnaire was used to screen for risk factors at the onset of the study and again annually, to determine the status of dog and cat ownership from year to year.The prevalence of sensitization to any allergen increased from 20.6% at 7 and 8 years of age to 30.4% at 11 and 12 years of age. In both age periods, the most common allergen was cat allergen, followed by dog, birch, and timothy grass allergens. The cumulative incidence during the 4-year period was 13.8%. The strongest risk factor for sensitization at 7 to 8 years, as well as development of sensitization during the 4-year period, was a family history of allergy. A significant inverse association between cat and dog ownership and the prevalence of type 1 allergy was found, especially for children living with cats and/or dogs before 7 and 8 years of age, and was most pronounced among children who persistently had lived in a house with a cat.The authors concluded that, despite the presence of a cockroach- and dust mite-free environment, the incidence of allergic sensitization between the ages of 7 to 8 years and 11 to 12 years was high in northern Sweden. The major risk factor for incident and prevalent cases was a family history of allergy. Although cat allergen was the most common allergen of sensitization, keeping a cat or dog at home was not related to an increased risk of sensitization to these allergens. Therefore, avoiding cats and dogs at home is not protective against sensitization.It should be noted that steps were taken in the analysis of the data to avoid risk for bias of pet ownership selection, in terms of primary prevention (avoidance of pets in a family with a known history of allergy) as well as secondary prevention (removal of pets after allergy diagnosis). Furthermore, although only sensitization was addressed in this article, additional data concerning clinical outcomes within the same longitudinal cohort were published and showed a lower prevalence of asthma among children with cats in the home.

The Editors’ Choice

The Editors’ Choice

Health hazards to humans associated with domestic pets.

Allergy to pets, particularly when manifested as asthma, is an important health hazard. The health impact of severe clinical disease associated with allergy to pets can be minimized by avoidance of pets. Many individuals with milder disease keep their pets and obtain medications for relief of their allergy symptoms. Bird fancier's disease can result in profound deterioration of pulmonary function, and requires avoidance of bird exposure. Animal bites are the commonest health hazard of domestic pets and result in tissue damage and infection risk. Bites are treated by cleaning the wound, and appropriate use of antibiotics and tetanus prophylaxis. Diverse infectious diseases are transmitted to humans by their pets; these diseases are particularly dangerous to immunocompromised individuals. The infectious diseases can be partly prevented by avoiding ill animals and by washing of hands following exposure to pets or pet-derived secretions. They can be treated by appropriate antibiotics and/or specific immune globulins and/or vaccines.

Pets, allergy and respiratory symptoms in children.

The relationship between pet ownership and respiratory allergy and symptoms was investigated in a population of 3344 Dutch children of 6-12 years old. Pet ownership was defined by the presence of cats, dogs, birds and/or rodents in the home. The reported prevalence of respiratory allergy and symptoms was lower among children of current pet owners than among children of parents who owned no pets. When past pet ownership was taken into account, however, a different picture emerged. The lowest prevalence of respiratory allergy and symptoms was found in children of current pet owners who had no pets in the past. The next lowest prevalence was found in children of current pet owners who had had pets in the past also. The next highest prevalence was found in children who never had pets in their life. The highest prevalence of reported pet allergy, chronic cough, wheeze, attacks of shortness of breath with wheezing, and doctor-diagnosed asthma was found in children who had pets in the past but not anymore. Past cat ownership especially was associated with a high prevalence of pet allergy and doctor-diagnosed asthma. Almost 2% of the population reported to never have owned pets for health reasons, and more than 12% reported removing pets from the home for health reasons in the past. These results show that selective avoidance and removal of pets leads to distortions of cross-sectional associations between pet ownership and respiratory allergy and disease among children.