Effect of Household Air Pollution on the Gut Microbiome and Virome of Adult Women Living in Uganda

BACKGROUND: Emerging observational studies suggest
that air pollution can influence the gut microbiome. However, this
association is often highly confounded by factors, such as diet and
poverty. The gut virome may influence respiratory health independent
of the gut microbiome. We recently demonstrated in a randomized waitlist-controlled
trial (ClinicalTrials.gov NCT03351504) that a clean lighting intervention
reduced the level of personal exposure to air pollution among adult
women in rural Uganda. OBJECTIVES: To determine the effect
of a solar lighting intervention on changes to the gut microbiome
and virome and secondarily to determine the association between these
changes on lung health. METHODS: Between 2018 and 2019,
we collected stool samples and assessed respiratory symptoms and spirometry
from 80 adult women living in rural Uganda at baseline and 12 and
18 months postrandomization. The intervention group received a solar
lighting system after randomization, while the waitlist-controlled
group received one at 12 months. Deep metagenomics sequencing of stool
was performed and profiled for nonviral and viral taxonomic composition.
The primary analysis focused on pre- vs postintervention changes due
to
power considerations, adjusting for potential confounding by age,
diet, antibiotic use, and season. A sensitivity analysis was conducted
using intention-to-treat principles. When comparing pre- vs postintervention
periods, we used sparse partial least-squares models to identify nonviral
and viral signatures of reduced air pollution exposure. Mixed effects
models were used to evaluate changes in health outcomes as well as
associations between microbial signatures of reduced air pollution
exposure and health. RESULTS: The average age was 39.2
years. The solar lighting intervention led to larger changes in viral
compared to nonviral microbial community structure and differential
abundance of bacteria, eukaryotes, and viruses. Provision of solar
lighting systems was associated with a reduction in the presence of
respiratory symptoms from 57.1% to 36.1% (p = 0.002),
while there was no impact on lung function. Microbiome and virome
signatures had AUCs of 0.74 and 0.76, respectively, in predicting
pre- vs postintervention stool samples. Microbiome signatures were
associated with a lower risk of respiratory symptoms (OR = 0.68 (0.49
– 0.94), p = 0.020). CONCLUSION: Among adult women living in rural Uganda, both nonviral and viral
components of the gut microbial community changed after a clean lighting
intervention. Microbiome signatures reflective of lower air pollution
exposures were associated with improved respiratory symptoms. These
observations suggest that air pollution may influence lung health
through the gut-lung axis, warranting further exploration in future
intervention studies.