Exploring the associations between parent-reported biological indoor environment and airway-related symptoms and allergic diseases in children.

Objectives: Asthma and allergic rhinitis are diseases which require special attention in childhood. Risk factors for these diseases are manifold and include environmental factors. Previous studies have shown associations between indoor mould and respiratory diseases in children. Besides indoor mould, organic waste storage, potted plants, pets and crowding could influence the microbial indoor environment at home and the respiratory health of children. Our aim was therefore to explore the associations of these factors with airway-related symptoms and respiratory diseases in preschoolers.

Methods: In this cross-sectional study we evaluated data based on parent-questionnaires regarding the health of their children from the 2014/2015 Health Monitoring Units (GME) in Bavaria. Bivariate and multivariate odds ratios (OR) with 95% confidence intervals (95%-CI) were calculated with logistic regression to explore associations between exposures (visible mould, organic waste storage, potted plants, pets and crowding) and outcome variables (doctor diagnosed allergic rhinitis with symptoms in the last 12 months, doctor diagnosed asthma with symptoms in the last 12 months, 12 month prevalence of symptoms such as dry cough at night without a cold, wheeze, wheeze attacks and allergic rhinitis symptoms).

Results: We analysed data from 4732 children (response rate 56.7%) with a mean age of 5.3 years. Visible mould was present in 4.7% of all households and associated with doctor diagnosed asthma with symptoms in the last 12 months [aOR 2.16 (95%-CI 1.01-4.63)], wheeze in the last 12 months [aOR 1.60 (95%-CI 1.0-2.50)] and allergic rhinitis symptoms in the last 12 months [aOR 1.75 (95%-CI 1.07-2.87)]. Crowding was associated with dry cough at night without a cold in the last 12 months [aOR 1.71 (95%-CI 1.42-2.05). The other indoor factors showed no association with respiratory health of the children.

Conclusion: Our results, in line with previous studies, showed positive associations between visible mould at home and airway-related symptoms and allergic diseases in children irrespective of the effect of the other considered indoor exposures. Despite the low prevalence of mould exposure in our study population, our results suggest intervention should be taken for those who do have visible mould exposure at home.