Prenatal and postnatal household air pollution and longitudinal growth trajectories: results from long-term follow up of the GRAPHS cohort

Background: There is limited evidence on the long-term effects of household air pollution (HAP) exposure during critical developmental windows and longitudinal growth trajectories in childhood. Methods: We leveraged a longitudinal pregnancy cohort from rural communities in central Ghana with repeated personal monitoring of prenatal and postnatal carbon monoxide (CO) and fine particulates (PM2.5). Child growth was measured at 1 year of age (n = 919), and annually from age 4 through 9 years (n = 698). Using generalized linear mixed-effects models adjusted for relevant confounders, we quantified separately, the age-specific associations between prenatal and postnatal CO and PM2.5, and z-scores of height-for-age (HAZ), weight-for-age (WAZ) and body mass index (BMI)-for-age (BMIZ) in primary models. Secondary models assessed the risk of being in a worse growth category compared with a better category e.g., for HAZ, stunted or at risk of stunting versus normal, or stunted versus at risk or normal). Results: Prenatal CO had the most consistent association with growth. Higher prenatal CO was associated with lower HAZ from age 1 through 9 with peak effect at age 4: adjusted β = −0.08; 95% CI = −0.12, −0.03; p = 0.002 per doubling), and WAZ from 7 through age 9 (peak effect was at age 9: adjusted β = −0.05; 95% CI = −0.09, −0.003; p = 0.04 per doubling). Results were similar for the ordered categories of HAZ and WAZ. Sex did not modify these associations. Conclusions: Higher HAP exposure, as indexed by prenatal CO during critical developmental windows may contribute substantially to long-term poor linear growth throughout childhood.