Prenatal and Postnatal Household Air Pollution Exposure and Infant Growth Trajectories: Evidence from a Rural Ghanaian Pregnancy Cohort

Abstract

Background: The exposure-response association between prenatal and postnatal household air pollution (HAP) and infant growth trajectories is unknown.

Objectives: To evaluate associations between prenatal and postnatal HAP exposure and stove interventions on growth trajectories over the first year of life.

Methods: The Ghana Randomized Air Pollution and Health Study enrolled n=1,414 pregnant women at ≤24wk gestation from Kintampo, Ghana, and randomized them to liquefied petroleum gas (LPG), improved biomass, or open fire (control) stoves. We quantified HAP exposure by repeated, personal prenatal and postnatal carbon monoxide (CO) and, in a subset, fine particulate matter [PM with an aerodynamic diameter of ≤2.5μm (PM2.5)] assessments. Length, weight, mid-upper arm circumference (MUAC) and head circumference (HC) were measured at birth, 3, 6, 9, and 12 months; weight-for-age, length-for-age (LAZ), and weight-for-length z (WLZ)-scores were calculated. For each anthropometric measure, we employed latent class growth analysis to generate growth trajectories over the first year of life and assigned each child to a trajectory group. We then employed ordinal logistic regression to determine associations between HAP exposures and growth trajectory assignments. Associations with stove intervention arm were also considered.

Results: Of the 1,306 live births, 1,144 had valid CO data and anthropometric variables measured at least once. Prenatal HAP exposure increased risk for lower length [CO odds ratio (OR)= 1.17, 95% CI: 1.01, 1.35 per 1-ppm increase; PM2.5 OR= 1.07, 95% CI: 1.02, 1.13 per 10-μg/m3 increase], lower LAZ z-score (CO OR= 1.15, 95% CI: 1.01, 1.32 per 1-ppm increase) and stunting (CO OR= 1.25, 95% CI: 1.08, 1.45) trajectories. Postnatal HAP exposure increased risk for smaller HC (CO OR= 1.09, 95% CI: 1.04, 1.13 per 1-ppm increase), smaller MUAC and lower WLZ-score (PM2.5 OR= 1.07, 95% CI: 1.00, 1.14 and OR= 1.09, 95% CI: 1.01, 1.19 per 10-μg/m3 increase, respectively) trajectories. Infants in the LPG arm had decreased odds of having smaller HC and MUAC trajectories as compared with those in the open fire stove arm (OR= 0.58, 95% CI: 0.37, 0.92 and OR= 0.45, 95% CI: 0.22, 0.90, respectively).

Discussion: Higher early life HAP exposure (during pregnancy and through the first year of life) was associated with poorer infant growth trajectories among children in rural Ghana. A cleaner-burning stove intervention may have improved some growth trajectories. https://doi.org/10.1289/EHP8109.

Trial registration: ClinicalTrials.gov NCT01335490.

Figures

Figure 1.

CONSORT diagram of mother–infant dyads in the Ghana Randomized Air Pollution and Health Study. All mother–infant dyads with valid maternal prenatal and child postnatal CO had at least one valid anthropometric measure and were included in the growth trajectories construction. In the child follow-up section, the deaths of children at >7 d of age did not have any recorded fieldworker follow-up. Note: CO, carbon monoxide; LPG, liquified petroleum gas.

Figure 2.

(A) Latent class growth trajectories for (a) weight, (b) length, (c) head circumference, and (d) MUAC. Weight, length, head circumference, and MUAC were measured at birth and at 3, 6, 9, and 12 months, and latent class growth analyses were employed to construct trajectories for each measurement. In general, trajectories appear distinct at birth although differences in slope are visualized through 6 months of life. (B) Latent class growth trajectories for (a) WAZ, (b) LAZ, and (c) WLZ calculated from 3 months of age using the 2006 WHO child growth standards. z-Score trajectories suggest that trajectories of wasting (WLZ<−2), stunting (LAZ<−2), and underweight (WAZ<−2) are largely present at 3 months of age and persist through 12 months of age. Note: LAZ, length-for-age z-score; MUAC, mid-upper arm circumference; WAZ, weight-for-age z-score; WLZ, weight-for-length z-score; WHO, World Health Organization.