Bronchiolitis Obliterans Pops Up in Home Microwave

DENVER, Sept. 5 -- A microwave-popcorn addict who found the aroma of the freshly made snack to be irresistibly intoxicating has developed bronchiolitis obliterans, suggested a pulmonologist here.
He may be the first person outside the realm of the flavoring and snack-food industry to develop so-called popcorn lung, said Cecile Rose, M.D., the acting head of environmental and occupational health sciences at National Jewish Research and Medical Center.
In a July 18 letter to the FDA, which just came to light, Dr. Rose reported that the man, who consumed several bags of extra-butter flavored bags of microwave popcorn for several years, had significant lung disease.
His symptoms were similar to those seen in some workers exposed to diacetyl, a compound used to impart the buttery flavor in microwave popcorn, said Dr. Rose.
But the man's only exposure to the chemical was in the bag after bag of butter-flavored microwave popcorn he consumed daily, said Dr. Rose, also an associate professor at the University of Colorado School of Medicine.
While drawing a causal connection from a single case is difficult, Dr. Rose wrote, "we have no other plausible explanation" for the man's condition.
The report comes as two of the major producers of microwave popcorn -- ConAgra Foods and Pop Weaver -- announced they will no longer use diacetyl to flavor their microwave popcorn. (ConAgra's popcorn is marketed under the Orville Redenbacher and Act II trade names.)
Dr. Rose's patient, she wrote, was diagnosed with bronchiolitis obliterans after he complained of progressively worsening respiratory symptoms, including cough and shortness of breath.
Serial pulmonary function testing showed a progressively worsening fixed airflow limitation, with a lack of bronchodilator response and a normal diffusion capacity for carbon monoxide.
"This is the pattern of lung physiologic abnormalities described in affected workers," Dr. Rose wrote.
High resolution CT scans of the man's chest showed bronchial wall thickening, bronchiectasis, mosaic attenuation, and expiratory air trapping -- again similar to images seen in affected workers.
Lung biopsy showed diffuse hyperinflation, a relative lack of small airways, and bronchioles in various stages of obliteration, Dr. Rose reported. The man has also shown a progressive decline in one-second forced expiratory volume (FEV1) despite treatment with oral corticosteroids.
Dr. Rose said measurements in the man's home during microwave popcorn preparation showed levels "similar" to those seen in the plant where the affected workers were first described.
Heated diacetyl vaporizes and the vapor has been linked to bronchiolitis obliterans among flavoring, popcorn, and most recently chemical plant workers. (See: Hunt Narrows for 'Popcorn Lung' Culprit)
Dr. Rose's patient routinely broke open the popcorn bags and inhaled the vapor because he enjoyed its aroma, the New York Times reported.
Since stopping his popcorn binges, the man has lost 50 pounds and his lung function has improved slightly, Dr. Rose said.
The FDA has been studying the diacetyl issue since the first report of bronchiolitis obliterans among workers making microwave popcorn, published in the New England Journal of Medicine in 2002.
Along with the letter to the FDA, Dr. Rose sent similar reports to the CDC, the Environmental Protection Agency, and the Occupational Health and Safety Administration.
She told the Seattle Post-Intelligencer that none of the governmental agencies has called to learn more, but that industry representatives were interested in the report.