title: Determinants of early-life lung function in African infants.
abstract: BACKGROUND
  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.
  
  
  OBJECTIVE
  To assess the determinants of early lung function in African infants.
  
  
  METHODS
  Infants 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.
  
  
  RESULTS
  Successful 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.
  
  
  CONCLUSIONS
  We 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.
authors.affiliation: Department of Paediatrics and Child Health, Red Cross War Memorial Children's Hospital and MRC Unit on Child and Adolescent Health, University of Cape Town, Cape Town, South Africa.
authors.forename: Diane
authors.identifier: http://orcid.org/0000-0002-7712-6774
authors.initials: D
authors.lastname: Gray
authors.affiliation: Department of Paediatrics and Child Health, Red Cross War Memorial Children's Hospital and MRC Unit on Child and Adolescent Health, University of Cape Town, Cape Town, South Africa.
authors.forename: Lauren
authors.initials: L
authors.lastname: Willemse
authors.affiliation: Department of Paediatrics and Child Health, Red Cross War Memorial Children's Hospital and MRC Unit on Child and Adolescent Health, University of Cape Town, Cape Town, South Africa.
authors.forename: Ane
authors.initials: A
authors.lastname: Visagie
authors.affiliation: Children's Lung, Environment and Asthma Research, Child Health Research Centre, University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Dorottya
authors.initials: D
authors.lastname: Czövek
authors.affiliation: Division of Epidemiology and Biostatistics, Department of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa.
authors.forename: Polite
authors.initials: P
authors.lastname: Nduru
authors.affiliation: Department of Paediatrics and Child Health, Red Cross War Memorial Children's Hospital and MRC Unit on Child and Adolescent Health, University of Cape Town, Cape Town, South Africa.
authors.forename: Aneesa
authors.initials: A
authors.lastname: Vanker
authors.affiliation: Department of Psychiatry and MRC Unit on Anxiety and Stress Disorder, University of Cape Town, Cape Town, South Africa.
authors.forename: Dan J
authors.initials: DJ
authors.lastname: Stein
authors.affiliation: Department of Psychiatry and MRC Unit on Anxiety and Stress Disorder, University of Cape Town, Cape Town, South Africa.
authors.forename: Nastassja
authors.initials: N
authors.lastname: Koen
authors.affiliation: Children's Lung, Environment and Asthma Research, Child Health Research Centre, University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Sly
authors.affiliation: Children's Lung, Environment and Asthma Research, Child Health Research Centre, University of Queensland, Brisbane, Queensland, Australia.|Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary.|Department of Pulmonology, University of Szeged, Szeged, Hungary.
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Hantos
authors.affiliation: Telethon Kids Institute, Australia Centre for Child Health Research, University of Western Australia, Perth, Western Australia, Australia.|Faculty of Health Sciences, School of Physiotherapy and Exercise Science, Curtin University, Perth, Western Australia, Australia.
authors.forename: Graham L
authors.initials: GL
authors.lastname: Hall
authors.affiliation: Department of Paediatrics and Child Health, Red Cross War Memorial Children's Hospital and MRC Unit on Child and Adolescent Health, University of Cape Town, Cape Town, South Africa.
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Zar
mesh_terms: D001554:Benzene / Q000633:toxicity; D004781:Environmental Exposure / Q000009:adverse effects; D005260:Female; D006801:Humans; D007223:Infant; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008431:Maternal-Fetal Exchange; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D012129:Respiratory Function Tests / Q000379:methods*; D012307:Risk Factors; D012737:Sex Factors; D013019:South Africa; D011795:Surveys and Questionnaires
chemical_list: D001554:Benzene
keywords: Clinical Epidemiology; Paediatric Lung Disaese; Respiratory Measurement; Tobacco and the lung