Recruitment of a racially and ethnically diverse sample into a physical activity efficacy trial

Healthy People 2010 underscores the relevance of eliminating health disparities. Thus, it is paramount to create interventions that promote health for all individuals.

This study examined differences in rates of and reasons for ineligibility among non-Hispanic blacks and whites in a randomized controlled physical activity intervention study.

Participants (1245 adults) responded to community advertising for the research study. Eligibility at the four pre-randomization assessment sessions was determined by self-reported medical information, resting EKG, 7-Day Physical Activity Recall, fitness test and Stage of Change. We used t-tests to examine the rates of eligibility among participant subgroups.

Blacks had higher rates of overall ineligibility (86.9%) than whites (75.1%; p < 0.01) and were more likely to be ineligible due to lack of interest or no-show at a pre-randomization appointment (35.4% vs. 24.3%; p < 0.01). Blacks were more likely to be ineligible for medical reasons after the telephone screen (16.3% vs. 7.8%; p = 0.01).

This study did not use a random sampling of potential participants from each of the racial/ethnic groups and thus, there is the potential for selection bias.

Blacks were more likely to choose not to enroll in the study due to a lack of interest, but had similar rates of overall medical ineligibility to whites. This highlights the importance of strategies that enhance interest among blacks, who initially respond to recruitment advertising.