Children with asthma who live near fast-food restaurants have lower lung function changes

Key takeaways:

• Restaurants are a source of particulate matter air pollution at 2.5 µm.
• Associations between changes in lung function and proximity to restaurants remained after controlling for nearby roadways and BMI.

WASHINGTON — Children with asthma who lived within 500 meters of a fast-food restaurant had smaller changes in lung function during an intervention, according to data presented at the American Thoracic Society International Conference.

This association was strongest among children who lived within 300 meters of a fast-food restaurant, suggesting a threshold effect, Franziska Rosser, MD, MPH, ATSF, division of pulmonary medicine, department of pediatrics, University of Pittsburgh School of Medicine, and colleagues wrote.

The research began with an investigation into the sources of particle inequities in Allegheny County, Pennsylvania, including the unequal distribution of particulate matter at the 2.5 µm scale (PM_2.5).

Franziska Rosser

“The two sources that they found were traffic-related air pollution and restaurants,” Rosser told Healio.

Severe asthma exacerbations, poor asthma control and lower lung function in children have been associated with long-term exposure to PM_2.5, the researchers said, adding that commercial cooking has been identified as a source of PM_2.5.

“I went to the literature, thinking, ‘What do we know about this in pediatrics and in kids with asthma?’ And we couldn’t find anything,” Rosser said.

The researchers analyzed prospective data from 80 children aged 6 to 16 years (mean age, 10.2 years; 61% boys; 66% Black) with mild persistent asthma who were using inhaled corticosteroids and participated in the 48-week VDKA Study, which was designed to examine the impact of vitamin D supplementation on children with asthma.

Also, the researchers limited their study to children from Allegheny County because they only had information about fast-food restaurants in that area.

Outcomes included severe and moderate asthma exacerbations, asthma control, quality of life, percent predicted forced vital capacity (FVC), FEV₁ and the ratio of FEV₁ to FVC. The researchers also examined changes in asthma control, quality of life and spirometry measures.

Using data from the Western Pennsylvania Regional Data Center, the researchers identified fast-food restaurants in the area and calculated residential distance to the nearest restaurant for each participant in the study (median, 903 m).

The researchers did not find any associations between proximity to a restaurant and changes in asthma exacerbations, quality of life or control. However, Rosser noted other studies that have found a threshold effect on lung function in children with asthma who live near a major roadway.

“We found the same thing looking at restaurants,” Rosser said. “Kids living near a fast-food restaurant had reduced lung function over time.”

Among the 18 children (23%) in the cohort who lived within 500 meters of a fast-food restaurant, the change in percent predicted FEV₁ was –11.5 (95% CI, –22.6 to –0.4), and the change in percent predicted FVC was –9.2 (95% CI, –18.1 to –0.3).

Similarly, results for the eight children (10%) who lived within 300 meters of a fast-food restaurant included –26.7 (95% CI, –41.4 to –11.9) for change in percent predicted FEV₁, –20.6 (95% CI, –32.6 to –8.7) for change in percent predicted FVC and –8.2 (95% CI, –14.9 to –1.5) for change in percent predicted FEV₁/FVC.

Since these restaurants were located on or near major roadways, the researchers thought that the effect might be coming from the roads instead of the restaurants. But the effects persisted after the researchers controlled for the roadways.

Additionally, the researchers accounted for monthly and annual average PM_2.5 totals. The magnitude of the P values for these figures differed, Rosser said, but they also did not have a large impact on the results once the researchers controlled for them as well.

“What that suggests is that there’s probably a threshold effect of living near a restaurant,” Rosser said.

The researchers also adjusted their models for BMI, since proximity to these restaurants could be a marker for poor diet. However, Rosser noted that the researchers did not have dietary information for these participants, so they could not determine what impact diet may have had on these results.

Socioeconomics may have had an impact on these results as well, Rosser said, adding that asthma is a health inequity in the United States.

“It overburdens Black and Puerto Rican children, and it overburdens under-resourced children,” she said. “So, this cohort already is enriched for the population simply because of our health inequities in the United States.”

The geography of Allegheny County, which is very hilly with rivers in its valleys, may have had an impact too.

“PM_2.5 tends to be along the rivers,” Rosser said. “Air pollution isn’t able to travel. It gets trapped.”

Although proximity to fast-food restaurants appeared to have a threshold effect on lung function changes in children with asthma, Rosser said that it would be difficult to draw conclusions based on a sample size of 80.

“I need a cohort. I need collaborators. I need a larger replication,” Rosser said. “I think it does warrant further study, particularly in larger cohorts with dietary information, with other economic information.”

Despite these limitations, Rosser still sees value in the results from this cohort.

“I think it highlights the importance again for us as physicians of paying attention to environmental factors that our patients face,” she said.

For more information:

Franziska Rosser, MD, MPH, ATSF, can be reached at franziska.rosser2@chp.edu.