Abstract
Rationale
Lung function is adversely affected by exposure to household air pollution (HAP). Studies of HAP intervention and lung development in children are limited: a single study performed spirometry on children born during a randomized control trial (RCT) in Guatemala, beginning at the age of 5 years. We investigated the impact of pre- and post-natal exposure to HAP on lung growth of children starting at the age of 2 years.
Methods
A RCT conducted in Ibadan, Nigeria between June 2013-October 2015 recruited healthy pregnant non-smoking women, who cooked regularly with firewood/kerosene and randomized them at ultrasound-determined 18 weeks gestational age to receive CleanCook ethanol stove or continue to cook with firewood/kerosene. The 208 children born to these two groups of women- firewood/kerosene (A,n=103) and ethanol (B,n=105), participated in this study. Oscillometry, an objective non-invasive measurement of lung function having the potential to examine both small and large airway obstruction independently, was used to assess lung function in these children. Airways resistance (R: a measure of central and peripheral airway caliber, which includes the resistance of the oropharynx and larynx, trachea, large and small airways, lung, and chest wall tissue) at 5 Hz and 19 Hz, airways reactance (X: amount of recoil generated against that pressure wave) at 5 Hz and 19 Hz, resonant frequency (Fres: frequency at which there is a transition in the lungs from passive distension to active stretch) and reactance area (AX: area under the reactance curve between 5 Hz and Fres) were measured. Personal exposure monitoring of mothers to particulate matter less than 2.5pm diameter (PM2.5) during pregnancy and household level monitoring of PM2.5 during follow-up was performed.
Results
All the 208 children were able to perform oscillometry successfully and were comparable with respect to their age, height, weight and body mass index. The difference between R5 and R19 (R5-R 19), which is an index of the small-airways resistance and indicative of small airways obstruction was significantly higher among the children born to firewood-/kerosene-users compared with those born to ethanol-users (p=0.015). No significant difference was found between the two groups in any of the other oscillometric parameters.
Conclusions
Oscillometry is a simple and effort-independent measure of pulmonary function in young children. Transitioning to ethanol, a clean fuel for cooking during early fetal development may be beneficial for later-life lung development of children.
Funding
Global Alliance for Clean Cookstoves through United Nations Foundation. Susan and Richard Kiphart Family
