Associations of improved air quality with lung function growth from childhood to adulthood: The BAMSE study

Background The beneficial effect of improving air quality on lung function development remains understudied. We assessed associations of changes in ambient air pollution levels with lung function growth from childhood until young adulthood in a Swedish cohort study. Methods In the prospective birth cohort BAMSE (Children, Allergy, Environment, Stockholm, Epidemiology), spirometry was conducted at the 8-year (2002–2004), 16-year (2011–2013) and 24-year follow-ups (2016–2019). Participants with spirometry data at 8 years and at least one another measurement in subsequent follow-ups were included (1509 participants with 3837 spirometry measurements). Ambient air pollution levels (particulate matter≤2.5 μm [PM 2.5 ], particulate matter≤10 μm [PM 10 ], black carbon [BC] and nitrogen oxides [NOx]) at residential addresses were estimated using dispersion modelling. Linear mixed-effect models were used to estimate associations between air pollution exposure change and lung function development. Results Overall, air pollution levels decreased progressively during the study period. For example, the median (interquartile range, IQR) of PM 2.5 decreased from 8.24 (0.92) μg·m −3 during 2002–2004 to 5.21 (0.67) μg·m −3 during 2016–2019. At the individual level, for each IQR reduction of PM 2.5 the lung function growth rate increased by 4.63 ml year −1 (95%CI:1.64–7.61, p<0.001) for FEV 1 and 9.38 ml year −1 (95%CI: 4.76–14.00, p<0.001) for FVC. Similar associations were also observed for reductions of BC and NO x . Associations persisted after adjustment for potential confounders, and were not modified by asthma, allergic sensitization, overweight, early-life air pollution exposure or antioxidant dietary intake. Conclusions Long-term reduction of air pollution is associated with positive lung function development from childhood to young adulthood.