In low-resource settings, the use of biomass fuel for cooking is a common practice that contributes to indoor air pollution and has significant health implications for infants and children. The HAPIN trial, a randomized controlled trial conducted in multiple countries, aimed to evaluate the effectiveness of a biomass cooking fuel intervention during pregnancy in reducing household air pollution and improving infant growth outcomes. However, the trial’s findings revealed that the intervention had little impact on infant growth and pneumonia rates, raising questions about the adequacy of the intervention and the overall complexity of the problem.
The cooking fuel intervention successfully reduced exposure to household air pollution, as indicated by decreased levels of fine particulate matter (PM2.5). However, there was no significant difference in severe infant pneumonia incidence between the intervention and control groups. The incidence rate ratio for pneumonia was 0.96, indicating that the intervention did not provide a substantial reduction in pneumonia cases. Additionally, stunting, a measure of impaired growth, did not significantly differ between the two groups. These findings suggest that the biomass cooking fuel intervention did not yield the desired outcomes in terms of reducing infant pneumonia and promoting healthy growth.
The researchers speculate that the timing and nature of the intervention may have contributed to its limited impact. The intervention may have needed to begin earlier during pregnancy or even before conception to have a more significant effect. Swapping out biomass fuel for an unvented liquefied petroleum gas (LPG) stove may not have been “clean enough” to address the range of pollution sources in the cooking ecosystem. While the gas stove itself is relatively clean, other household pollution sources and behavioral adjustments could have negated the expected benefits of the intervention. Furthermore, despite reducing personal exposures to fine particulate matter, the measured exposures during the intervention were still higher than the recommended guidelines by the World Health Organization (WHO).
The lack of impact seen in the HAPIN trial suggests that the problem of indoor air pollution and its effects on infant health is more complex than previously thought. Interventions focusing solely on changing cooking stoves may not be sufficient to address the economic and quality-of-life issues that impact exposure levels. Previous studies have also shown limited effectiveness in reducing pneumonia cases by replacing biomass cooking stoves with cleaner alternatives. Therefore, a comprehensive solution to the problem will require a combination of technology, policy, and behavioral interventions to tackle various pollution sources and systemic factors.
Several other factors may have influenced the trial’s failure to impact infant health outcomes. Vaccination against specific pathogens, such as Haemophilus influenzae type B and Streptococcus pneumoniae, could have played a role in reducing pneumonia rates, limiting the intervention’s potential impact. Pandemic-related protection measures and lower personal exposures to fine particulate matter during the trial period might have contributed to the overall lack of significant differences in outcomes. Additionally, the interruption and limitations imposed by the COVID-19 pandemic on home assessments may have impacted the data collected and the trial’s overall results.
The effectiveness of biomass cooking fuel interventions in low-resource settings remains a challenging issue. The HAPIN trial highlighted the limited impact of a cooking fuel intervention during pregnancy on infant growth and pneumonia rates. The findings suggest the need for more comprehensive approaches that address not only the type of cooking fuel but also other pollution sources and behavioral factors. Future interventions should consider starting earlier during pregnancy or before conception and involve a combination of technology, policy, and behavioral strategies. The complexity of the problem requires a multi-faceted approach to make a significant difference in reducing indoor air pollution and improving infant health outcomes.