Air pollution linked to increased risk of Obesity

US: Air pollution has a significant impact on population health and has been identified as the fifth leading risk factor for mortality worldwide.

Mostof the disease burden that is attributable to air pollution results from chronic noncommunicable diseases, including respiratory disease and type 2 diabetes. In addition to exposure-induced effects on mortality, work has shown that long-term exposure is also associated with greater risk of obesity.

Breathing dirty air takes a heavy toll on gut bacteria, boosting the risk of several chronic illnesses, suggested by researchers at the University of Colorado Boulder. The study, published online in the journal Environment International is the first to link air pollution to changes in the structure and function of the human gut microbiome - the collection of trillions of microorganisms residing within us.

The study was composed of 101 participants who were recruited from the Meta-AIR (Metabolic and Asthma Incidence Research) study between 2014 and 2017 at the University of Southern California (USC). The primary aim of the Meta-AIR study was to investigate the impacts of ambient and near-roadway exposures on metabolic health and adiposity in young adults.

Senior author Tanya Alderete, an assistant professor of integrative physiology, used cutting-edge whole-genome sequencing to analyze fecal samples from 101 young adults in Southern California to investigate what might be going on inside the gut. The researchers looked at data from air-monitoring stations near the subjects' addresses to calculate their previous-year exposure to ozone (which forms when emissions from vehicles are exposed to sunlight), particulate matter (hazardous particles suspended in the air), and nitrous oxide (a toxic byproduct of burning fossil fuel).

Of all the pollutants measured, ozone had the greatest impact on the gut by far, accounting for about 11% of the variation seen between study subjects - more of an impact than gender, ethnicity or even diet. Those with higher exposure to ozone also had less variety of bacteria living in their gut."This is important since lower (bacteria) diversity has been linked with obesity and Type 2 diabetes," stated by Alderete.

Subjects with higher exposure to ozone also had a greater abundance of a specific species called Bacteroides caecimuris, which has an important association with obesity. Subjects with higher exposure to ozone also had a greater abundance of a specific species called Bacteroides caecimuris, which has an important association with obesity.

Overall, the 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.

Policymakers should consider moving parks, playgrounds and housing developments away from busy roads and high pollution areas and invest more in meeting or exceeding air quality standards concluded by Alderete.

The study was relatively small and has some limitations, including the fact that stool samples were taken only once.

For further reading click on the following link,

http://dx.doi.org/10.1016/j.envint.2020.105604