Determinants of early-life lung function in African infants.

Nastassja Koen,Zoltán Hantos,Polite Nduru,Lauren Willemse,Peter D Sly,Aneesa Vanker,Diane Gray,Graham L Hall,Heather J Zar,Dan J Stein,Dorottya Czövek,Ane Visagie

doi:10.1136/thoraxjnl-2015-207401

Abstract

BackgroundLow lung function in early life is associated with later respiratory illness. There is limited data on lung function in African infants despite a high prevalence of respiratory disease.AimTo assess the determinants of early lung function in African infants.MethodInfants enrolled in a South African birth cohort, the Drakenstein child health study, had lung function measured at 6–10 weeks of age. Measurements, made with the infant breathing via a facemask during natural sleep, included tidal breathing, sulfur hexafluoride multiple breath washout and the forced oscillation technique. Information on antenatal and early postnatal exposures was collected using questionnaires and urine cotinine. Household benzene exposure was measured antenatally.ResultsSuccessful tests were obtained in 645/675 (95%) infants, median (IQR) age of 51 (46–58) days. Infant size, age and male gender were associated with larger tidal volume. Infants whose mothers smoked had lower tidal volumes (−1.6 mL (95% CI −3.0 to −0.1), p=0.04) and higher lung clearance index (0.1 turnovers (95% CI 0.01 to 0.3), p=0.03) compared with infants unexposed to tobacco smoke. Infants exposed to alcohol in utero or household benzene had lower time to peak tidal expiratory flow over total expiratory time ratios, 10% (95% CI −15.4% to −3.7%), p=0.002) and 3.0% (95% CI −5.2% to −0.7%, p=0.01) lower respectively compared with unexposed infants. HIV-exposed infants had higher tidal volumes (1.7 mL (95% CI 0.06 to 3.3) p=0.04) compared with infants whose mothers were HIV negative.ConclusionWe identified several factors including infant size, sex, maternal smoking, maternal alcohol, maternal HIV and household benzene associated with altered early lung function, many of which are factors amenable to public health interventions. Long-term study of lung function and respiratory disease in these children is a priority to develop strategies to strengthen child health.

Highlights

Low lung function in early life is associated with later respiratory illness
We aimed to investigate the impact of antenatal and early-life exposures on lung function measured at 6 weeks of age in African infants enrolled in a birth cohort
Infant testing was done at a median (IQR) of 51 (46–58) days, and anthropometry of enrolled infants is shown in table 1

Summary

Introduction

Low lung function in early life is associated with later respiratory illness. There is limited data on lung function in African infants despite a high prevalence of respiratory disease. ▸ In addition to known factors such as growth, sex and maternal smoking, maternal alcohol during pregnancy, exposure to household benzene and having an HIV-positive mother alter lung function in early life. ▸ Low lung function in early life is associated with later respiratory disease. Lung function in early life being associated with lung function impairment and chronic respiratory illness in later life.[3] Identifying prenatal and postnatal factors associated with early lung disease, as measured by lung function, will provide a better understanding of how early-life exposures influence childhood lung disease and possibly provide insights into prevention of subsequent chronic respiratory illness. In utero and early-life factors that damage or impair lung growth may have a considerable impact on early lung function

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