Long-term ambient air pollution exposure and respiratory impedance in children: A cross-sectional study

Objectives: The present study was aimed to compare the respiratory impedance of children residing in areas with different ambient air pollution (AAP). Methods: A comparative cross-sectional pilot study was carried out in healthy school children of two cities in India i.e. Agra and Bhopal. Agra is one of the most polluted cities of India and AAP of Agra is much higher as compared to Bhopal, the reference city in the present study. The respiratory impedance was measured at 5, 11, and 19 Hz by forced oscillation technique (FOT). The anthropometric parameters, respiratory resistance at 5 Hz (R5), small airway resistance (R5-19), and reparatory reactance at 5 Hz (X5) of children from above two cities were compared by Student's t-test. Results: A total 114 children (57 boys) from Agra and 151 children (76 boys) from Bhopal aged 9-16 years were recruited. The children from Agra were younger (11.9 +/- 1.9 yr vs. 13.1 +/- 2.2 yr, p < 0.001) as compared to Bhopal, though their anthropometric parameters were comparable. The magnitude of R5 (5.53 +/- 1.81 cmH(2)0/L/s vs. 5.10 +/- 1.77 cmH(2)0/L/s, p = 0.05) = X5 (-1.46 +/- 0.65 cmH(2)0/L/s vs. -1.17 +/- 0.63 cmH(2)0/L/s, p < 0.001), and R5-19 (0.79 +/- 0.79 cmH(2)0/L/s vs. 0.56 +/- 0.78 cmH(2)0/L/s, p = 0.023) in children of Agra were higher as compared to children of Bhopal. The differences in impedance were significantly higher between boys, but not between girls. Conclusions: The present study demonstrates a higher magnitude of small airway dysfunction in children exposed to high AAP. A future study involving larger samples and longitudinal measurements of respiratory impedance will provide better insights.