A risk factor  is anything that increases a person’s chance of developing cancer. Although risk factors often influence the development of cancer, most do not directly cause cancer. Some people with several risk factors never develop cancer, while others with no known risk factors do. However, knowing your risk factors and talking about them with your doctor may help you make more informed lifestyle and health care choices.
The exact cause of Hodgkin lymphoma is not known, but the following factors may raise a person’s risk of developing Hodgkin lymphoma:
Age. People between age 15 and 40 and people older than 55 are more likely to develop Hodgkin lymphoma.
Gender. Men are slightly more likely to develop Hodgkin lymphoma than women overall, although the nodular sclerosis subtype is more common among women.
Family history. Brothers and sisters of people with Hodgkin lymphoma have a higher chance of developing the disease, although the likelihood is small.
Virus exposure. People who are infected with EBV (see Overview ) may be at increased risk for developing some types of Hodgkin lymphoma. However, there are probably several other factors involved. EBV is a very common disease, but Hodgkin lymphoma is very uncommon. People who have human immunodeficiency virus  also have a higher risk of developing Hodgkin lymphoma, particularly lymphocyte-depleted Hodgkin lymphoma (see Overview ).
It is important to note that, although viruses may be involved in the development of Hodgkin lymphoma, there is no evidence that this type of cancer is contagious. Close contact with someone with Hodgkin lymphoma does not increase a person’s risk of developing the disease.