Multiple epidemiologic, geographic, clinical, and immunologic factors are involved in the etiology of AP. This study proposes a clear line for research directed at specific risk factors that refer to an individual's clinical, allergic, health, and socioeconomic status. Further study should also investigate the etiologic role of diet in AP and the molecular mechanisms behind the development of AP to establish whether AP is caused by exposure to polycyclic aromatic hydrocarbons.