Current pet ownership modifies the adverse association between long-term ambient air pollution exposure and childhood asthma

Pets and related allergens modify the association between early life DEHP exposure and respiratory outcomes in children

INTRODUCTION

Throughout the perinatal period children are exposed to complex mixtures, including indoor chemicals such as phthalates, and biological agents. However, few studies focus on interactions between early-life co-exposures to shed light on how co-exposures modify their individual effects. Therefore, our study aims to assess whether early-life exposure to pets and related biological agents, namely pet allergens and endotoxin, modifies the association between di-(2-ethylhexyl) phthalate (DEHP) and asthma and wheeze in preschoolers to gain insight into interactions.

METHODS

Using data from a Canadian birth cohort study (CHILD), we conducted two complementary analyses on respiratory outcomes. First, we combined pet ownership with DEHP measurements from house dust (N = 726). Second, we focused on a subgroup of children with exposure measurements of both DEHP and biological agents in dust (N = 261). We used multivariable logistic regression models to assess whether pets and quantified biological agent levels modify associations between DEHP and asthma at 5 years and recurrent wheeze between 2 and 5 years. Interaction terms were included in the models and stratified analyses were further conducted.

RESULTS

Associations between DEHP and asthma and wheeze were modified by pet ownership and related biological agents. For persistent/recurrent wheeze, the association with DEHP became larger among children with dogs at home and with higher dog allergens (p-interaction <0.1) and became smaller and insignificant when exposed to cats. Similarly, for asthma, the association with DEHP tended to be larger among children with dogs (also higher dog allergens) and among children without cats (also lower cat allergens) at home, respectively. Endotoxin levels modified the association between DEHP and persistent wheeze (p-interaction <0.1).

CONCLUSIONS

Early-life exposure to pets and related biological agents may modify the associations between phthalates and asthma and wheeze in children. Heterogeneity in single exposure studies could be a result of differences in co-exposures among studies.

Prevalence of asthma and allergic rhinitis in children exposed to pets: a meta-analysis

PURPOSE

Pet exposure has always been controversial with childhood asthma and allergic rhinitis. We aimed to understand the prevalence of asthma and allergic rhinitis in children exposed to pets by meta-analysis.

METHODS

We searched articles published from Jan 1, 2012 to Dec 31, 2022 in the Embase, PubMed, Cochrane Library, and Web of Science databases. We included a cross-sectional study that reported the prevalence of asthma and allergic rhinitis in children exposed to pets. Furthermore, we performed subgroup analyses according to pet type and age.

RESULTS

In 14 selected studies, the meta-analysis results showed that the pooled prevalence of asthma in children exposed to pets was 19.0% (95% CI 13.3-24.7%), and the pooled prevalence of allergic rhinitis in children exposed to pets was 25.5% (95% CI 12.4-38.5%). The prevalence of asthma in children exposed to cats and dogs was 16.4% (95% CI 9.9-22.8%) and 12.5% (95% CI 8.7-16.2%), respectively. The prevalence of allergic rhinitis was 24.9% (95% CI 2.9-47.0%) and 24.1% (95% CI 2.6-45.6%), respectively. The prevalence of asthma in pet-exposed children was 17.1% (95% CI 12.3-22.0%) in the adolescence group (> 10 years) and 26.3% (95% CI 12.2-40.3%) in the childhood group (0-10 years). The prevalence of allergic rhinitis was 8.6% (95% CI 7.2-10.0%) in the adolescence group and 46.3% (95% CI 44.0-48.6%) in the childhood age group.

CONCLUSIONS

The prevalence of asthma and allergic rhinitis in children exposed to pets is different. Exposure to pet cats is more prone to illness, and younger children are more susceptible to disease than older children.

Incidence of grass and weed sensitization in Bangkok, Thailand: a clinical study

Background

Allergic rhinitis (AR) is a prevalent public health concern globally, significantly impacting quality of life. In Thailand, the prevalence of AR is rising, with grass and weed pollen identified as primary outdoor triggers.

Objectives

This study aimed to (1) assess patterns of pollen sensitization in Thai AR patients and (2) investigate correlations between demographics/clinical data and SPT results.

Methods

A total of 121 individuals aged ≥18 years with clinically diagnosed AR were recruited. Skin prick testing (SPT) was performed using a panel of commonly encountered tropical grass and weed pollen extracts. SPT wheal sizes and clinical symptom scores were recorded. Correlations between SPT outcomes and symptom scores were analyzed.

Results

Among the participants, 104 (85.95%) exhibited positive SPT reactions to at least one pollen type. Nutsedge (76/121), para grass (57/121), and Bermuda grass (48/121) were the most frequently identified allergens. Hurricane grass elicited the strongest reaction, evidenced by the highest average wheal size (6.2 mm). Poly-sensitization was observed in 77 (63.6%) of the SPT-positive individuals, with most cases involving two different pollen extracts (35/77). Notably, AR severity positively correlated with both average wheal size and the number of positive SPT tests.

Conclusion

This study highlights nutsedge, para grass, and Bermuda grass as major allergenic pollen sources for Thai AR patients. Including nutsedge, hurricane grass, and careless weed in clinical SPT panels is recommended for improved diagnostic accuracy. Additionally, the positive correlation between AR severity and pollen reaction strength emphasizes the importance of implementing patient education and avoidance strategies.

Indoor air pollution is associated with respiratory symptoms in children in urban Vietnam

Exposure to indoor air pollution (IAP) is a leading environmental risk for respiratory diseases. We investigated the relationship between respiratory symptoms and polluting indoor activities such as smoking, cooking and contact with pets among children in Ho Chi Minh City (HCMC), Vietnam. A cross-sectional survey applied a multistage sampling method in 24 randomly selected secondary schools across the city. Approximately 15,000 students completed self-administrated questionnaires on risk factors and respiratory health outcomes within the preceding 12 months. Data were analyzed using a multivariable logistic regression model with robust standard errors. Wheeze was the most common respiratory symptom (39.5 %) reported, followed by sneezing and runny nose (28.3 %). A small percentage of students self-reported asthma (8.6 %). Approximately 56 % of participants lived with family members who smoked. A positive association between exposure to indoor secondhand smoke and respiratory symptoms was observed, with adjusted odds ratios (aOR) of 1.41 (95 % CI: 1.25-1.60, p < 0.001) for wheezing and 1.64 (95 % CI: 1.43-1.87, p < 0.001) for sneezing and runny nose, respectively. Using an open stove fuelled by coal, wood, or kerosene for cooking was associated with wheeze (aOR: 1.36, CI 95 %: 1.10-1.68, p = 0.01) and sneezing and runny nose (aOR: 1.36, CI 95 %: 1.09-1.69, p = 0.01). In the present study, IAP was associated with adverse health outcomes, as evidenced by an increase in respiratory symptoms reported within the previous 12 months.