Associations of dog and cat ownership with wheezing and asthma in children: Pilot study of the Japan Environment and children's study

Respiratory conditions and health symptoms associated with air pollution amongst children aged six years and below in Melusi Informal Settlement, Tshwane Metropolitan Municipality, South Africa: a cross-sectional study

BACKGROUND

Respiratory conditions and health symptoms associated with air pollution in children are a major public health concern, as their immune systems and lungs are not yet fully developed. This study aimed to assess self-reported respiratory conditions and health symptoms associated with air pollution sources amongst children aged six years and below in Melusi informal settlement, Tshwane Metropolitan Municipality, South Africa.

METHODS

With a quantitative cross-sectional study design, parents/caregivers of children aged six years and below (n = 300) from eight Early Childhood Development Centres were invited to participate in the study. This study employed complete sampling, and data was collected using the modified International Study of Asthma and Allergies in Children. The chi-square and multiple logistic regression models were used to analyze data, with p < 0.05 in the adjusted odds ratios considered as being statistically significant.

RESULTS

Three models were run to examine the predictors of wheezing in the past 12 months, dry cough, and itchy-watery eyes. The model for asthma was excluded, as only seven participants reported having asthma. Wheeze in the past 12 months was associated with participants living in the area for more than three years (OR 2.96 95%CI: 1.011-8.674). Furthermore, having a dog in the house in the past 12 months was associated with wheeze in the past 12 months (OR 5.98 95%CI: 2.107-16.967). There was an association between duration of stay in a residence and dry cough prevalence (OR 5.63 95%CI: 2.175-14.584). Trucks always or frequently passing near homes was associated with itchy-watery eyes (OR 3.27 95%CI: 1.358-7.889). 59% (59%) of participants perceived the indoor air quality in their homes to be good, while 6% perceived it as poor. In contrast, 36% of participants perceived the outdoor air quality to be good, and 19.7% perceived it as poor.

CONCLUSION

The association between perceived air pollution exposure, self-reported respiratory conditions, and health symptoms amongst children is complex. Further research is required to better understand the multifaceted nature of air pollution and its impact on the health of children.

Association of longitudinal pet ownership with wheezing in 3-year-old children using the distributed lag model: the Japan Environment and Children's Study

BACKGROUND

Time-varying exposures like pet ownership pose challenges for identifying critical windows due to multicollinearity when modeled simultaneously. The Distributed Lag Model (DLM) estimates critical windows for time-varying exposures, which are mainly continuous variables. However, applying complex functions such as high-order splines and nonlinear functions within DLMs may not be suitable for situations with limited time points or binary exposure, such as in questionnaire surveys.

OBJECTIVES

(1) We examined the estimation performance of a simple DLM with fractional polynomial function for time-varying binary exposures through simulation experiments. (2) We evaluated the impact of pet ownership on childhood wheezing onset and estimate critical windows.

METHODS

(1) We compared logistic regression including time-varying exposure in separate models, in one model simultaneously, and using DLM. For evaluation, we employed bias, empirical standard error (EmpSE), and mean squared error (MSE). (2) The Japan Environment and Children's Study (JECS) is a prospective birth cohort study of approximately 100,000 parent-child pairs, registered across Japan from 2011 to 2014. We applied DLM to the JECS data up to age 3. The estimated odds ratios (OR) were considered to be within critical windows when they were significant at the 5% level.

RESULTS

(1) DLM and the separate model exhibited lower bias compared to the simultaneously model. Additionally, both DLM and the simultaneously model demonstrated lower EmpSEs than the separate model. In all scenarios, DLM had lower MSEs than the other methods. Specifically, where critical windows is clearly present and exposure correlation is high, DLM showed MSEs about 1/2 to 1/200 of those of other models. (2) Application of DLM to the JECS data showed that, unlike other models, a significant exposure effect was observed only between the ages of 0 and 6 months. During that periods, the highest ORs were 1.07 (95% confidence interval, 1.01 to 1.14) , observed between the ages of 2 and 5 months.

CONCLUSIONS

(1) A simple DLM improves the accuracy of exposure effect and critical windows estimation. (2) 0-6 months may be the critical windows for the effect of pet ownership on the wheezing onset at 3 years.

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.

Exposure to dogs and cats and risk of asthma: A retrospective study

Findings on the relationship between pet exposure and asthma in western countries are inconsistent. This retrospective study examined the association of owning a dog or cat with the onset of asthma in Japanese people. We also investigated whether there is a critical window during which exposure to dogs and cats can reduce the risk of asthma by stratifying the analysis by the age at which pet ownership began. We analyzed data collected in an internet survey conducted by the Japan Pet Food Association in 2021. Valid data were obtained from 4290 participants for analysis of dog ownership and 4308 participants for analysis of cat ownership. In these respective groups, 41.2% had owned a dog and 26.5% had owned a cat. During the follow-up period, 5.7% of dog owners and 14.8% of non-dog owners developed asthma, as did 5.6% of cat owners and 13.5% of non-cat owners. On binomial logistic regression analysis, participants who had not owned a dog had an odds ratio (OR) of 2.01 (95% confidence interval (CI): 1.45-2.78) of developing asthma compared to those who had owned a dog after adjustment for sociodemographic characteristics. The corresponding OR of asthma onset among participants who had not owned a cat was 2.24 (95%CI: 1.56-3.23). Stratified analysis showed that while younger participants who had not owned a dog had higher ORs of developing asthma, those who had not owned a cat had similar ORs of asthma onset across all age categories. These results suggest that while there may be a critical window in early life during which exposure to dogs can prevent asthma onset, the protective effect of cat exposure is constant across all ages in Japan.

Exposomal research in the context of birth cohorts: What have they taught us?

OBJECTIVE

To review birth cohorts with an exposomal approach and their key outcomes and challenges. Exposome encompasses all human environmental exposures from conception onward. The impact of environmental exposures is greatest in critical stages of life, including fetal and early childhood. Birth cohorts provide a good study setting to assess exposome in the sensitive periods of life. Here, we review birth cohorts with an exposomal approach and their key outcomes and challenges.

DATA SOURCES

MEDLINE was searched for birth cohorts that have used an exposomal approach.

STUDY SELECTIONS

Relevant studies in English language were selected and reviewed.

RESULTS

The outcomes of birth cohorts with an exposomal approach improve our understanding of the association between environmental exposures and childhood diseases. For example, results from The Canadian Healthy Infant Longitudinal Development Study suggest an association between first trimester exposure to traffic-related air pollution and increased risk of allergic sensitization at 12 months of age (P = .6). In a smaller Canadian birth cohort study, it was found that regular use of air fresheners (adjusted P = .04) and presence of mold in the residence (adjusted P < .001) were associated with early childhood wheezing and cough. The application of emerging molecular omics technologies and new analytical tools has facilitated the comprehensive assessment of exposome in birth cohorts.

CONCLUSION

Birth cohort studies with an exposomal approach improve our understanding of the origin of childhood diseases by examining a complex network of environmental exposures during pregnancy and years beyond birth. International collaboration is required to develop large birth cohorts for better and more extensive assessment of exposome with standardized protocols and new statistical frameworks.