Lauren Willemse

Lung Function in African Infants in the Drakenstein Child Health Study: Impact of Lower Respiratory Tract Illness.

Rationale: Lower respiratory tract illness is a major cause of childhood morbidity and mortality. It is unknown whether infants are predisposed to illness because of impaired lung function or whether respiratory illness reduces lung function. Objectives: To investigate the impact of early life exposures, including lower respiratory tract illness, on lung function during infancy. Methods: Infants enrolled in the Drakenstein child health study had lung function at 6 weeks and 1 year. Testing during quiet natural sleep included tidal breathing, exhaled nitric oxide, and multiple breath washout measures. Risk factors for impaired lung health were collected longitudinally. Lower respiratory tract illness surveillance was performed and any episode investigated. Measurements and Main Results: Lung function was tested in 648 children at 1 year. One hundred and fifty (29%) infants had a lower respiratory tract illness during the first year of life. Lower respiratory tract illness was independently associated with increased respiratory rate (4%; 95% confidence interval [CI], 1.01‐1.08; P = 0.02). Repeat episodes further increased respiratory rate (3%; 95% CI, 1.01‐1.05; P = 0.004), decreased tidal volume (−1.7 ml; 95% CI, −3.3 to −0.2; P = 0.03), and increased the lung clearance index (0.13 turnovers; 95% CI, 0.04‐0.22; P = 0.006) compared with infants without illness. Tobacco smoke exposure, lung function at 6 weeks, infant growth, and prematurity were other independent predictors of lung function at 1 year. Conclusions: Early life lower respiratory tract illness impairs lung function at 1 year, independent of baseline lung function. Preventing early life lower respiratory tract illness is important to optimize lung function and promote respiratory health in childhood.

Lung function in African infants: A pilot study

The burden of childhood respiratory illness is large in low and middle income countries (LMICs). Infant lung function (ILF) testing may provide useful information about lung growth and susceptibility to respiratory disease. However, ILF has not been widely available in LMICs settings where the greatest burden of childhood respiratory disease occurs.

Lung function and exhaled nitric oxide in healthy unsedated African infants

Population‐appropriate lung function reference data are essential to accurately identify respiratory disease and measure response to interventions. There are currently no reference data in African infants. The aim was to describe normal lung function in healthy African infants.

Respiratory impedance in healthy unsedated South African infants: Effects of maternal smoking

Non‐invasive techniques for measuring lung mechanics in infants are needed for a better understanding of lung growth and function, and to study the effects of prenatal factors on subsequent lung growth in healthy infants. The forced oscillation technique requires minimal cooperation from the individual but has rarely been used in infants. The study aims to assess the use of the forced oscillation technique to measure the influence of antenatal exposures on respiratory mechanics in unsedated infants enrolled in a birth cohort study in Cape Town, South Africa.

Determinants of early-life lung function in African infants.

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. Aim To assess the determinants of early lung function in African infants. Method 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. Conclusion 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.