Final answer:
The most important risk factor for Hodgkin lymphoma is infectious mononucleosis caused by the Epstein-Barr virus (EBV).
Step-by-step explanation:
The most important risk factor for Hodgkin lymphoma is infectious mononucleosis caused by the Epstein-Barr virus (EBV). EBV is associated with a variety of diseases, including mononucleosis and Burkitt lymphoma. Exposure to EBV is widespread, and the virus primarily resides within B lymphocytes. Having a history of infectious mononucleosis increases the risk of developing Hodgkin lymphoma.