Exposure to air pollution alters gut microbiome composition, subsequently increases the risk of obesity, diabetes, and other chronic illnesses.
The study, the first of its kind, used whole-genome sequencing to establish whether air pollutants affected the gut microbiome of 101 young adults.
Several pollutants were identified during sequencing. However, researchers found that adults exposed to higher levels of ozone (O3) had less microbial diversity and more significant kinds of gut microbiota, which are associated with obesity and disease.
“Researchers identified 128 bacterial species influenced by increased ozone exposure. Some may impact the release of insulin, the hormone responsible for ushering sugar into the muscles for energy. Other species can produce metabolites, including fatty acids, which help maintain gut barrier integrity and ward off inflammation,” according to a statement by the researchers.
Participants of the study were mostly male and Hispanic. Researchers investigated the relationship between gut microbiota and diabetes risk by gathering data on the average prior year exposure to ambient and near-roadway air pollutants based on residential addresses.
The researchers found that “of all the pollutants found to be associated with microbiome composition, including nitrous oxides (NOx) and fine particulate matter, O3 exposure had the most significant associations at the phylum and species level of gut bacteria. Four bacterial species were associated with NO2, and five species were associated with total NOx.”
The findings were adjusted for confounders such as age, sex, ethnicity, BMI, season of study visit, parental education (a proxy for socioeconomic status), energy intake, and macronutrients (i.e., protein, fat, carbohydrates, fiber).
The percent variation of the gut microbiome composition was determined by different levels of exposure to air pollutants: 4% for total NOx, 4.4% for NO2, and 11.2% for O3 concentrations.
The study found the pathways most likely to be involved in obesity and type 2 diabetes to be those gene pathways involved in fatty acid synthesis /degradation, which were enriched with higher O3 exposure.
Tanya Alderete, Ph.D., an author of the study, explains: “We know from previous research that air pollutants can have a whole host of adverse health effects. The takeaway from this paper is that some of those effects might be due to changes in the gut. A lot of work still needs to be done, but this adds to a growing body of literature showing that human exposure to air pollution can have lasting, harmful effects on human health.”
Despite recent efforts to improve the air quality in the US, air pollution remains a public health challenge that affects many states throughout the country, and O3 pollution has worsened.
“In December, the Environmental Protection Agency downgraded the Denver metro and North Front Range regions to ‘serious non-attainment’ status for failing to meet national ozone standards,” according to a statement. “Regions of eight other states, including some in California, Texas, Illinois, Connecticut, Indiana, New Jersey, New York, and Wisconsin, were also penalized for high ozone.”
8.8 million people die annually worldwide as a result of air pollution, which is considered the fifth leading risk factor for mortality.
The authors of the study emphasize that “most of the disease burden that is attributable to air pollution results from chronic noncommunicable diseases, including respiratory disease and type 2 diabetes.”
Air pollution is considered a major social determinant of public health. In a study published in The American Journal of Managed Care® (AJMC®) researchers used an applied machine-learned to predict healthcare utilization based on socioeconomic determinants of care.
Researchers found that air quality was a significant determinant associated with health risk, which “had a relative value more twice that of the next determinant, income. Air quality had a relative value more than 30-fold higher than the lowest-weighted determinant, percentage in group living quarters.”
The study led to the conclusion that “Not only does poor air quality lead to lower health outcomes, higher risks of obesity and diabetes, and increased hospitalizations, it also compounds healthcare costs incurred by patients and providers.”
- Exposure to air pollutants influences the composition of the gut microbiome, which has subsequent increases in health risks.
- O3 exposure is associated with decreased gut microbial diversity and increased levels of Bacteroides caecimuris.
- Poor air quality is associated with lower health outcomes, higher risks of obesity and diabetes, and increased hospitalizations, and compounds healthcare costs incurred by both patients and providers.
Melillo, Gianna. “Air Pollution Alters Gut Microbiome, Increasing Risks for Diabetes, Obesity, Study Says.” Air Pollution Alters Gut Microbiome, Increasing Risks for Diabetes, Obesity, Study Says, AJMC, 17 Mar. 2020
Mit Suthar, PharmD. Candidate, LECOM School of Pharmacy