Short-term air pollutant exposure and infant lung function in a South African birth cohort

Abstract

Introduction: The developing lung is susceptible to ambient air pollutants, with short and long term exposure associated with early childhood effects.

Aim: To determine the association of short-term exposure to nitrogen dioxide (NO2) and particulate matter (PM10) on lung function (LF) in infants aged 6 weeks, 6, 12 and 24 months.

Methods: LF was measured by multiple breath washout and tidal breathing in non-sedated infants. Two-week average exposure estimates for NO2 and PM10 (preceding the test date), was assessed by hybrid land use regression and dispersion modelling. Generalized linear mixed models adjusted for the repeated measures design.

Results: LF measurements were obtained from 165 infants, with 82 of them having repeat tests over the 24 months of age. Short-term exposure to NO2 and PM10, ranged from 16.31 – 17.35 µg/m3 and 32.28 – 34.39 µg/m3, respectively across age groups. Exposure to PM10 resulted in a decline in tidal volume at 6 weeks (β: -0.4mL/kg (95%CI: -0.9; 0.0), 6 months (β: -0.5mL/kg (95%CI: -1.0; 0.0) and 12 months (β: -0.3mL/kg (95%CI: -0.7; 0.0). PM10 was related to an increase in respiratory rate and minute ventilation, and a decline in functional residual capacity for the same age groups. Exposure to NO2 resulted in a decline in tidal volume months (β: -0.3mL (95%CI: -1.3mL (-3.1; 0.6)) and functional residual capacity (β: -4.7mL (-9.6; 0.1) at the 24-month age group, though only statistically significant for certain age groups.

Conclusion: Our study suggests that PM10 results in acute LF impairments among infants, while the association with NO2 appeared to show inconsistent changes for the parameters assessed, with no apparent trends observed.