Air Pollution Could Increase Risk of Reflux, Study Reveals

New analysis suggests an association between long-term exposure to air pollution and higher rates of gastro-oesophageal reflux disease (GERD).

It appears the air we breathe matters: exposure to traffic fumes and fine particles is linked with higher risk of reflux disease.

A new cohort survey, published on Frontiers in Public Health, reports that air pollution could be a driver behind gastro-oesophageal reflux disease (GERD), which can lead to symptoms such as heartburn and acidic burps.

Researchers from Xi’an Jiaotong University in China assessed the impact of breathing in different pollutants over a long period to see if there is a direct correlation with the development of GERD. They also looked at which groups and regions appeared more susceptible.

Why the study looked at air pollution

In 2021, air pollution was linked to 8.1 million deaths worldwide, making it the second leading risk factor for death, according to a State of Global Air Report.

Seventy-one per cent of air particles in the nose get transported to the gastrointestinal tract, according to the Integrated Science Assessment (ISA). The tract contains all the major organs of the digestive system, in humans including the oesophagus, stomach and intestines.

To understand how these pollutants are affecting gastrointestinal pathways, the researchers broke particulate matter down into three types:

• Inhalable particulate matter (PM₁₀)
• Coarse particulate matter (PM_5-10)
• Fine particulate matter (PM₅)

However, particles aren’t the only concern. Vehicle emissions, industrial processes and fuel combustion release nitrogen oxides, harmful gases, into the air. In addition to particulate matter, the study also looked at impact of:

• Nitrous oxides (NO_X)
• Nitrogen dioxide (NO₂)
• Nitic oxide (NO)

How the reflux pollutant study worked

To explore any correlations, the researchers used data from UK Biobank, a project that has examined the health of half a million UK adults from the late 2000s.

They analysed 289,000 volunteers, excluding anyone with cancer, GERD or GERD-like symptoms. Those without sufficient socioeconomic and pollutant data were also excluded from the study.

Air-pollution exposure was estimated using a standard model linked to residential addresses. Participants were then followed from 2010 to 2024 to see who received a GERD diagnosis.

During the assessment period, 11 per cent of the participants were diagnosed with GERD. The study found that the greater the exposure to particulate matter and traffic-related gases, the higher the chance of being diagnosed with GERD.

It also reported that women showed a stronger link for traffic-related gases, and that adults under 60 showed a stronger overall association than older adults.

The authors suggest one possible reason is that younger adults may spend more time outdoors, so they may breathe in more polluted air.

People who were overweight also showed a stronger association.

The pollution link was stronger among people with higher incomes or living in less-deprived areas; the authors note this may partly be because these groups are more likely to see a doctor, get tests and receive a formal diagnosis.

At a glance: patterns observed

• Under-60s: stronger pollution–reflux link than in older adults
• Women: stronger link for nitrogen oxides (traffic fumes)
• Overweight adults (BMI ≥25): stronger pollution–reflux link
• White participants: stronger pollution–reflux link than in other groups
• More affluent / less-deprived areas: stronger link; may reflect higher diagnosis rates
• England residents: particulate matter showed a stronger link than in Scotland/Wales
• without oesophagitis: stronger link than reflux with oesophagitis (no visible inflammation)
• Higher exposure: higher recorded reflux risk.

What does the study conclude

People who breathed more polluted air were more likely to be diagnosed with reflux over time. However, this is a link, not proof that pollution causes GERD.

If air quality affects reflux risk, cleaner air could benefit not just lungs and hearts but the oesophagus and stomach too.

The researchers suggest repeating the study in places with higher pollution, include younger people, and dig into how pollution might irritate the gut lining and trigger reflux.

Getting your reflux diagnosed

Peptest is a non-invasive test that looks for pepsin in saliva. Pepsin should be confined to the stomach; if it’s present in saliva, it indicates reflux is occurring.

An objective test result can support an earlier diagnosis and help you speak to the right healthcare professional about treatment options.

Order your Peptest home reflux testing kit online.