Formaldehyde exposure in homes is associated with increased levels of exhaled nitric oxide in healthy children

The Australian indoor goal for formaldehyde in non-occupational settings is 10Oppb. However formaldehyde has been associated with respiratory symptoms in both adults (1) and children (2) at levels below this guideline. No mechanisms for these findings have been established. In order to investigate the possible inflammatory effects of formaldehyde at low levels (typically found in the home) we measured exhaled nitric oxide (eNO) in 224 healthy children (6-13 years; 116 girls) and monitored formaldehyde levels in their homes. Formaldehyde was monitored in homes using passive sampling devices that were placed in the living room and child's bedroom for at least 3 days. Children made one visit to the Respiratory Medicine Department at Princess Margaret Hospital where they underwent a lung function test (spirometry) and measurements of exhaled nitric oxide using a fast response nitric oxide analyser (Seivers NOA280). There was no effect of formaldehyde levels measured in homes on lung function. There was, however, a small but significant increase in eNO levels in children living in homes with average formaldehyde levels >50ppb. Exhaled NO levels (Geometric mean) were 15.5ppb (95%CI 1Q.5-22.9ppb) for children from homes with formaldehyde concentrations >50ppb compared with 8.7ppb (7.9-9.6) for children from homes with formaldehyde concentrations <50ppb (p<0.05). These results suggest that exposure to formaldehyde in homes may invoke a sub-clinical inflammatory response in the airways of healthy children.