Inclusion of African Americans in genetic studies: what is the barrier?

Abstract

To facilitate an increase in the amount of data on minority subjects collected for genetic databases, the authors attempted to clarify barriers to African-American participation in genetic studies. They randomly sampled 78,072 subjects from the community (Missouri Family Registry, 2002-2007). Of these, 28,658 participated in a telephone screening interview, 3,179 were eligible to participate in the genetic study, and 1,919 participated in the genetic study. Response rates were examined in relation to the proportion of subjects in the area who were African-American according to US Census 2000 zip code demographic data. Compared with zip codes with fewer than 5% African Americans (average = 2% African-American), zip codes with at least 60% African Americans (average = 87% African-American) had higher proportions of subjects with an incorrect address or telephone number but lower proportions of subjects who did not answer the telephone and subjects who refused the telephone interview (P < 0.0001). Based on reported race from the telephone screening, 71% of eligible African Americans and 57% of eligible European Americans participated in the genetic study (P < 0.0001). The results of this study suggest that increasing the number of African Americans in genetic databases may be achieved by increasing efforts to locate and contact them.

Figure 1.

Introduction letter sent prior to a telephone screening call for a genetic study of nicotine dependence, St. Louis, Missouri, 2002–2007.

Figure 2.

Selection of participants for a genetic study of nicotine dependence, St. Louis, Missouri, 2002–2007. A) Initiation of the telephone interview; B) offer of study participation; C) signing of the informed consent form prior to participation in the study. Difference in participation rates between European Americans and African Americans: P < 0.0001.