Increasing participation in the national marrow donor program: A randomized trial

The current randomized trial tested messaging strategies to increase diverse student participation in the National Marrow Donor Program (NMDP). Undergraduate students (<i>N</i> = 361, 72.3% female; 58.4% nonwhite, ages 18-35) completed measures about facilitators and barriers to joining the NMDP and enrollment intentions. Participants were randomized to receive an emotional appeal (<i>n</i> = 181) or a rational appeal (<i>n</i> = 180) and then asked again about enrollment intentions. Participants answered 21% of marrow donation knowledge questions correctly, and higher knowledge and lower ambivalence were related to a greater likelihood of joining the NMDP. The emotional appeal increased the likelihood of registering more than the rational appeal. Race did not moderate the response to the intervention condition. Future studies seeking to increase participation by diverse young adults should target knowledge and emotional aspects of the need for donors. Trial registration NCT05595382.