BACKGROUND:
Exposure to household air pollution has been associated with numerous health problems, including impaired childhood linear growth and multimorbidity. Despite the implementation of various interventions and programs, the reduction in stunting rates remains very slow in sub-Saharan African countries. Beyond the classic covariates of stunting, which include diet and illness, the specific contribution of household air pollution to stunting has been poorly investigated in this region, where the majority of the population still relies heavily on polluting solid fuels for their basic energy needs.

METHODS:
A mixed study design, including prospective cohort, comparative cross-sectional, and systematic review with meta-analysis, was used. Data were collected from 280 children under the age of five, residing in households using solid fuel (exposed group, n = 140) and clean fuel (unexposed group, n = 140). The relationship between exposure to household air pollution and childhood linear growth was analyzed using Difference-in-Differences (DID) and Poisson regression statistical methods for identifying multi-morbidity risks.

RESULTS:
The systematic review and meta-analysis found that exposure to household air pollution was significantly associated with increased odds of child stunting [pooled estimate: Odds Ratio = 2.42, (95% CI: 1.45, 4.03), P < 0.0010]. Similarly, after controlling for all potential covariates, the average difference in the height-for-age Z score of children in households using solid fuel was 0.54 (-0.54, 95% CI -0.97, -0.12, P = 0.011). Furthermore, Children in households using solid fuel had a higher risk of childhood multimorbidity than those in households using clean fuel (AOR = 3.14, 95% CI [1.42-6.95], p < 0.001).

CONCLUSIONS:
Children exposed to household air pollution face reduced linear growth and a higher prevalence of multiple illnesses, underscoring the urgent need for integrated policies and targeted strategies to reduce exposure to household air and protect child health.