It is widely believed that racial and ethnic minority groups, especially in the US, are less willing to participate in health research than non-minority groups. According to this view, minority groups’comparative unwillingness to participate is due to a lack of trust in health research and health researchers, which traces to past abuses, particularly the Tuskegee Syphilis Study.
https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.0030040