Short-term Air Pollution Exposure Can Increase Severity of Fibrotic Sarcoidosis Respiratory Symptoms, Small Study Finds

A recent study shows that while lung function was unaffected, patients with fibrotic sarcoidosis report increased respiratory symptoms and decreased quality of life after short-term exposure to air pollution.

This small cohort study, titled “Short-Term Particulate Air Pollution Exposure is Associated with Increased Severity of Respiratory and Quality of Life Symptoms in Patients with Fibrotic Sarcoidosis,” was published in the International Journal of Environmental Research and Public Health. 

Approximately 10-20 percent of patients with chronic sarcoidosis will ultimately progress to a condition of chronic inflammation and fibrosis. Patients with fibrotic sarcoidosis often experience more severe respiratory systems accompanied by a decline in lung function, and treatment can involve corticosteroid therapy.

Although some risk factors for the development of fibrotic sarcoidosis are known, the role that short-term air pollution plays in this process is not well-known.

Exposure to air pollution is known to negatively affect patients with other pulmonary diseases such as chronic obstructive pulmonary disease, asthma, and cystic fibrosis, which share clinical features with fibrotic sarcoidosis.

In this study, researchers investigated if short-term exposure to air pollution is linked to lung function decline or increased symptoms in patients with fibrotic sarcoidosis.

The team looked at data previously collected in a randomized controlled trial evaluating a new treatment option for acute respiratory episodes in the U.S. state of Ohio. Sixteen patients with fibrotic sarcoidosis complicated by frequent exacerbations were included in the analysis.

The majority of participants were women (75 percent), and the median age was 59. One patient was a current smoker, while 10 others were former smokers.

Patients completed three or more tests between June 2013 and June 2015. These included lung function tests that evaluated forced expiratory volume in 1 second (FEV₁) and forced vital capacity (FVC).

Additionally, study participants completed several questionnaires that measured respiratory symptoms, such as cough, and the impact of respiratory symptoms on overall health, daily life, and perceived well-being.

Air pollution was measured using 18 air-quality monitors in southwestern Ohio. Some of these monitors measured small particulate matter (PM_2.5 ), while others measured ozone levels. Based on location, average pollutant exposure for 7, 10, and 14 days preceding each study visit was calculated for each patient.

Results showed that the average PM_2.5 was not associated with changes in lung function using the two different measures, FVC and FEV₁. Average ozone levels were not associated with changes in lung function, either.

However, using patient-reported questionnaires, the researchers found that PM_2.5 levels averaged over 14 days were associated with a lower lung-specific health status on one questionnaire, the King’s Sarcoidosis Questionnaire. Levels of PM_2.5 were not associated with respiratory symptoms measured using a different questionnaire.

Short-term ozone exposure was not associated with health status or respiratory symptoms as measured by any of the questionnaires.

According to the team, this is the first study to evaluate short-term exposure to air pollution and the exacerbation of symptoms in patients with fibrotic sarcoidosis.

“In this small cohort of patients with fibrotic sarcoidosis, PM_2.5 exposure was associated with increased severity of respiratory and quality of life symptoms,” the researchers said.

Nevertheless, the team said that “a larger sample size is needed to evaluate the association of short-term air pollution exposure with other health outcomes in fibrotic sarcoidosis.”