Explaining that popcorn lung has been around for years before vaping or even before the first recognised case identified in its name sake factory is not easy.
Popcorn lung is simply the name given to the case of bronchiolitis obliterans identified to have been directly caused Diacetyl exposure during the manufacturing of popcorn.
Smoking causes a multitude of pulmonary diseases but none of them will be called popcorn lung as cigarettes dont contain popcorn.
The smoking related equivalent to popcorn lung will be diagnosed as bronchiolitis or chronic obstructive pulmonary disease (copd).
Hopefully the below will explain better than i can.
https://www.sciencedirect.com/science/article/pii/S2214750015300767
Extract from above link
"Fixed airway obstruction, including BO disease, is a subset of conditions under the general category of chronic obstructive pulmonary disease or COPD"
BO standing for "Bronchiolitis obliterans"
Extract from above link
"Table 1. Generally accepted diagnostic criteria for bronchiolitis obliterans disease.
1.
Pulmonary function tests show clinically important fixed obstructive deficits indicating small airways disease without appreciable impacts on total lung volume and gas exchange measurements.
2.
The obstructive changes are resilient to treatment by corticosteroids or bronchodilators.
3.
The patients lungs show a mosaic pattern of attenuation on high resolution computed tomography (HRCT) scans indicating air trapping,
The diagnostic criteria used for BO disease overlap with the manifestations of other lung disorders having variable etiologies. For example, mosaic lung attenuation has also been observed in asthma and emphysema
[52,92]. There are also similarities with clinical presentation and pulmonary function testing between BO disease and other obstructive lung diseases
[52]. In addition to a detailed medical and exposure history, a lung biopsy is often essential to distinguish BO disease from various other diseases potentially affecting the bronchioles
[73].
Laohaburanakit and colleagues
[52] noted that:
In the case of BO that is not related to transplantation, the diagnosis is much more challenging and requires a high index of suspicion. The clinical presentation, as well as pulmonary function testing characteristics of BO, are non-specific and resemble other obstructive diseases such as asthma and COPD [chronic bronchitis and emphysema]. [] Surgical lung biopsy, either by open lung biopsy or video-assisted thoracoscopic surgery (VATS) is usually required when BO occurs outside of transplantation and the diagnosis cannot be made by transbronchial biopsy.