Air pollution spikes pose risk of delayed lung issues in CF patients: Study
Findings open the door for preventive strategies, researchers say
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Short-term increases in air pollution can trigger pulmonary exacerbations — disease flares marked by a sudden worsening in lung function — in people with cystic fibrosis (CF), a new study shows.
Notably, the study found that increased pollution doesn’t trigger exacerbations right away — the data suggest that if pollution is increased on a particular day, the risk of CF pulmonary exacerbations only increases in the days that follow, not on the day when there’s actually high pollution.
“The presence of lagged effects from ambient air pollution concentrations reframes exacerbations not as sudden events but as predictable outcomes of environmental stressors, opening the door to preventative strategies,” researchers wrote.
The study, “Acute Exposure to Fine Ambient Particulate Matter and Pulmonary Exacerbations in Cystic Fibrosis: A Case-Crossover Study,” was published in Atmospheric Environment: X.
Patients recorded lung function measurements at home
CF is a genetic disorder marked by thick, sticky mucus that builds up in the lungs and other organs. Studies have repeatedly shown that people with CF who are exposed to increased air pollution are more likely to experience pulmonary exacerbations. However, the exact relationship between day-to-day changes in pollution levels and the risk of pulmonary exacerbations in CF has not been clearly defined.
In this study, the researchers set out to more precisely delineate the relationship between short-term changes in pollution levels and lung function in CF patients.
“The purpose of our study was to evaluate whether short-term increases in [air pollution] are associated with pulmonary exacerbations in individuals with cystic fibrosis,” the researchers wrote.
To do this, the scientists used data from a clinical trial (NCT01104402) in which CF patients recorded regular at-home lung function measurements. Using participants’ home ZIP codes, they then cross-referenced lung function data with data on day-to-day pollution levels to identify associations between changes in air pollution and sudden decreases in lung function indicative of exacerbations. The scientists specifically evaluated a type of air pollution called PM2.5, referring to airborne particles less than 2.5 micrometers in diameter.
“By integrating high-resolution daily PM2.5 estimates with increased resolution in lung function measurements through home [lung function tests], we were able to capture exacerbation onset with greater temporal precision. This methodological advancement allowed us to uncover lagged associations at a daily level, demonstrating that acute changes in outdoor air pollution can act as triggers for sudden declines in lung [function] among individuals with CF,” the scientists said.
The analysis included data on 121 CF patients in the U.S. Results indicated that, if PM2.5 levels were elevated on a given day, the risk of a pulmonary exacerbation on that day was not significantly different from that on a day with lower pollution levels. But in the days after a spike in air pollution, pulmonary exacerbation risk increased significantly, with the effect rising from 18% on the first day after the spike to 23% on the third day.
“Our study provides novel evidence that short-term fluctuations in ambient PM2.5 are associated with an increased risk of exacerbations in individuals with CF. We observed elevated risk in exacerbation onset 1, 2, and 3 days following increased PM2.5 exposure,” the scientists wrote, adding that these data “provide new evidence that exacerbations may be triggered not by same-day exposures but by short-term environmental triggers that precede symptom onset.”
With the increasing availability of tools to monitor local air pollution levels, the researchers believe that understanding this relationship could help better guide care for people with CF in the future.
