Exposure to air pollution has been linked to various diseases in adults. However, no study has investigated the impact on children.
To understand the multifaceted impacts, scientists at Stanford University have investigated air pollution’s effects at the single-cell level in a cohort of school-aged children (6–8 years; n = 221). While simultaneously focusing on both the cardiovascular and immune systems in children, the study reveals that air pollution puts children at higher risk of disease in adulthood.
The study uncovered that early exposure to dirty air alters genes in a way that could lead to adult heart disease, among other ailments. The study provides early clues for clinical intervention before actual disease presentation and could change the way medical experts and parents think about the air children breathe.
Study lead author Mary Prunicki, director of air pollution and health research at Stanford’s Sean N. Parker Center for Allergy & Asthma Research, said, “I think this is compelling enough for a pediatrician to say that we have evidence air pollution causes changes in the immune and cardiovascular system associated not only with asthma and respiratory diseases, as has been shown before. It looks like even brief air pollution exposure can actually change the regulation and expression of children’s genes and perhaps alter blood pressure, potentially laying the foundation for increased risk of disease later in life.”
For the study, scientists used a combination of continuous daily pollutant concentrations measured at central air monitoring stations in Fresno, daily concentrations from periodic spatial sampling, and meteorological and geophysical data. This data is then used to estimate average air pollution exposures for one day, one week, and 1, 3, 6, and 12 months before each participant visit.
When scientists combined this data with health and demographics questionnaires, blood pressure readings, and blood samples, it showed warning signs.
Using a form of mass spectrometry, scientists analyzed immune system cells. This approach allowed more sensitive measurements of up to 40 cell markers simultaneously, providing a more in-depth analysis of pollution exposure impacts than previously possible.
Among their findings: Exposure to fine particulate known as PM2.5, carbon monoxide, and ozone over time is linked to increased methylation, an alteration of DNA molecules that can change their activity without changing their sequence. This change in gene expression may be passed down to future generations.
Air pollution exposure contributes to increment in monocytes, white blood cells that play a key role in the buildup of plaques in arteries. What’s more, it could predispose children to heart disease in adulthood. Although, future studies are needed to verify the long-term implications.
Study senior author Kari Nadeau, director of the Parker Center, said, “This is everyone’s problem. Nearly half of Americans and the vast majority of people worldwide live in places with unhealthy air. Understanding and mitigating the impacts could save a lot of lives.”
- Prunicki, M., Cauwenberghs, N., Lee, J. et al. Air pollution exposure is linked with methylation of immunoregulatory genes, altered immune cell profiles, and increased blood pressure in children. Sci Rep 11, 4067 (2021). DOI: 10.1038/s41598-021-83577-3