The study was presented on Wednesday by biostatistician Dr Soutrik Banerjee of the University of Ferrara, Italy, at the European Respiratory Society (ERS) congress in Barcelona.
“We know that indoor air quality in schools can be affected by pollutants, humidity, ventilation, temperature, dampness and biological agents like fungi and bacteria. However, much less is known about whether the types of bacteria growing in classroom dust are linked to children’s lung function”, said Banarjee.
The research focused on Streptomyces and Mycobacterium bacterial species, which naturally occur in dust, soil and water systems. It aimed to see whether higher exposure to those bacteria in the classroom is associated with children’s lung health across Europe, Banarjee added.
Researchers used the data from the SINPHONIE project (2010-2014), which covered 22 European countries and nearly 300 classrooms. To measure children’s lung function, the researchers used a spirometry test. This standard respiratory examination calculates the air volume that fits in the lungs and the speed at which it leaves the lungs during an exhale.
Impaired lung function appears when lungs can contain a smaller than normal amount of air, or the air cannot flow freely through the lungs. This can lead to feelings of tiredness and shortness of breath.
Researchers adjusted the results for age, sex, Body Mass Index (BMI), passive smoking, pet allergens, socioeconomic factors, school-building characteristics and local air pollution.
The findings highlighted that children in classrooms with higher levels of Streptomyces bacteria had slightly lower lung capacity, with FVC - the maximum amount of air they could force out after a deep breath - being 0.08 litres lower.
Higher levels of Mycobacterium were linked to a 0.06-litre reduction in FEV1, the amount of air expelled in the first second, and a 0.13-litre-per-second reduction in peak expiratory flow, the maximum speed at which air could be expelled.
“Although the reductions we found were modest for each child, they are statistically significant and could be important for the wider population”, Banarjee said. “The bacteria may either have a direct biological effect, or they may be indicators of other indoor environmental factors that influence lung function”, he added.
“While not all bacteria are harmful, these findings suggest that the classroom environment is important in children’s lung health and they support the idea that healthy school buildings matter”, said Professor Alexander Möller, the Head of the European Respiratory Society’s Pediatric Assembly.
He highlighted that schools should focus on good indoor air quality, adequate ventilation, moisture and mold control, regular cleaning and proper building maintenance, rather than trying to create sterile environments.
(sp/jh)
Source: PAP