Association between prenatal and early life household air pollution exposure and child lung function in rural Ghana

Abstract

BACKGROUND AND AIM: Impaired lung development in early childhood increases risk for future pulmonary disease. Millions of people worldwide are exposed to household air pollution (HAP), however the impact of early life HAP on childhood lung development is poorly described. Leveraging the Ghana Randomized Air Pollution and Health Study (GRAPHS) birth cohort, we examined associations between prenatal and early life HAP exposure, as indexed by carbon monoxide (CO), and age four lung function. METHODS: GRAPHS enrolled pregnant women prior to 24 weeks gestation. We quantified HAP exposure by repeated personal prenatal (maternal) and early life (child) carbon monoxide (CO) assessments. Mother-child dyads were followed prospectively and children performed impulse oscillometry (IOS) at age four years. For analyses, IOS lung function variables were converted to z-scores adjusting for age, sex, ethnicity, height and weight. We then employed multivariable generalized linear regression models to examine associations between prenatal and early childhood CO and IOS variables. Sex-specific effects were explored. RESULTS:Of the 699 study children, 612 (88%) performed acceptable IOS. Children were aged 4.1 years (0.35 SD) on average at the time of IOS and 52% (N=315) were female. In adjusted models, increased prenatal CO exposure was associated with increased R5 (R5 z-score β=0.17 (95% CI 0.00, 0.34) and R20 (β = 0.20 (95% CI 0.03, 0.37), indicative of increased total and large airway resistance, respectively. Exploratory analyses suggested that boys were more vulnerable to the effects of prenatal CO exposure on both R5 and R20. CONCLUSIONS:Higher prenatal HAP exposure, as indexed by CO, is associated with impaired lung function at age four years and boys may be more vulnerable. These findings add to the growing literature of the adverse health effects of early life HAP exposure on child health. KEYWORDS: household air pollution exposure, carbon monoxide, child lung function, sex-specific effects