Which one of the following options is a known risk factor for a person to be a carrier of Creutzfeldt-Jakob disease or variant Creutzfeldt-Jakob disease?

A family history is indeed recognized as a significant risk factor for Creutzfeldt-Jakob disease (CJD) and variant Creutzfeldt-Jakob disease (vCJD). This is primarily due to the genetic predisposition associated with certain forms of the disease, particularly the sporadic and familial types. Mutations in the prion protein gene (PRNP) can be inherited, leading to an increased likelihood of developing the disease among family members. Therefore, individuals with close relatives who have been diagnosed with CJD may have a heightened risk of being carriers.

While other factors such as drug addiction, history of institutionalization, and sexual promiscuity may be associated with various health risks, they are not directly linked to being carriers of CJD or vCJD. For instance, drug addiction or lifestyle choices do not influence the genetic or infectious components related to prion diseases. Understanding the hereditary nature of conditions associated with prion diseases is crucial for recognizing risk factors accurately.