Though it would be premature for the study to prompt any clinical changes in practice, Dr. Allen pointed out that the findings should raise clinicians’ awareness about the value of considering patients’ living areas and pollution exposure when evaluating GI symptoms.
“These data would lend support to the inclusive approach to an IBS diagnosis as opposed to a ‘rule-out’ diagnosis,” Dr. Allen said. “Additionally, we should investigate possible behavioral changes for patients exposed to environmental pollutants.”
He emphasized the importance of asking patients about their socioeconomic and environmental factors while helping them deal with GI disorders.
“These are complex and difficult histories to elicit during brief clinic encounters,” Dr. Allen said. “We need better ways to help patients understand their GI disorders in the context of their specific life stresses and avoid ordering multiple diagnostic tests when a different approach is needed to solve patients’ issues.”
The study’s biggest limitation is its ecologic design, which cannot link individual people’s exposures to their specific diagnosis. They also could not consider seasonal changes in pollutant levels or the possible interaction or cumulative effects of different pollutants. The authors also noted a number of other pollution exposures that they did not measure at all in this study, such as nitrogen dioxide, sulfur dioxide, heavy metals, or bacteria.
“Ecologic studies using claims data without a prespecified singular outcome, even when corrected for multiple comparisons, is at risk of confounding and bias,” Dr. Naik said. “This study will hopefully help with future environmental studies to understand the role of the environment and GI health.”
Dr. Okafor further cautioned that it’s likely premature to advocate for policy change right now based on these findings.
“We will need better temporal data to associate exposure to airborne pollutants and GI disease incidence and even severity,” Dr. Okafor said. “If it is possible to demonstrate this reliably, it may impact our ability to provide better care for our patients.”
As more research like this is conducted, however, it has the potential to improve how clinicians care for patients, Dr. Allen suggested.
“As we begin to understand the complex interactions of environment, social determinants of health, individual life stresses, and a person’s unique reaction to stress, we will be much better at helping patients live with GI symptoms and disorders,” Dr. Allen said. “We also can assign accountability for the externalities [costs] that environmental pollution causes.”
Dr. Allen, Dr. Naik, and the authors reported no conflicts of interest. The research was funded by the National Institutes of Health and Stanford University.