The TLP Study sought to determine if there is a difference between Blacks, Hispanics, and Whites concerning willingness to participate in biomedical studies, as assessed by the LOP Scale within the TLP Questionnaire. Our multivariate analyses revealed no statistically significant difference, overall, in mean. LOP Scale score for the three racial/ethnic groups. The multi-item LOP scale aimed to ensure that our measure of willingness to participate was psychometrically sound and capable of capturing some of the complexity and nuances of this particular concept.
For example, if one based the analysis of willingness to participate solely on Q16 from the TLP Questionnaire in a comparison of Blacks and Whites, a logistic regression analysis reveals that Blacks are less likely to participate as research subjects than non-Hispanic Whites (OR=0.70, p<.05) after adjusting for age, sex, education, and income. However, similarly adjusted logistic regression analyses comparing Blacks with Whites regarding the influence of who was running the study (Q17a-g) and what they would be asked to do in a study (Q18a-i), revealed that Blacks and Whites, on. the whole, were no different in their likelihood to participate based either on the who or on the what. Specifically, Blacks were somewhat more influenced than Whites by who was running the study as Blacks tended to report being somewhat less likely to participate than Whites based on the who, but not at a statistically significant level (OR=0.71, p=.07), in contrast to no differences on the what (OR=1.05, p=.78).
Thus, while we observed a null association, overall, concerning differences among the three racial/ethnic groups in their willingness to participate in biomedical research, answers to the individual components of the LOP Scale (Q16, Q17a-g, and Q18a-i) did provide useful insights into this complex concept. While Q16 (arguably the overall single best gestalt question on willingness to participate) showed a difference between Blacks and Whites in willingness to participate, this was counterbalanced by the findings from Q17a-g (who was running the study), and Q18a-I (what they would be asked to do in a study), both of which revealed that Blacks and Whites were equally likely to participate based, on both the who or the what condition. The in general differences between racial/ethnic groups (shown, by the data from Q16) disappeared when subjects were given specific study circumstances as to who was conducting the study or what subjects were asked to do within the study. Thus, it is quite clear that the concept of willingness to participate is a complex concept.
While these sub-analyses by the individual TLP Questionnaire questions 16, 17a-g and 18a-i provide detailed insights into the elements contained in the concept of willingness to participate, only the LOP Scale, taken as a whole, provides the in-depth probe most capable of providing the most valid single measure of this complex concept. Conversely, if these three individual questions (Q16, Q17a-g, and Q18a-i) had not been integrated into one variable to capture this complexity, the analysis could not have addressed the concept as a whole.
While there was no detectable difference observed in the LOP Scale across racial/ethnic groups, the data showed a statistically significant difference across the three racial/ethnic groups for the Guinea Pig Fear Factor (GPFF) Scale (p=.022, ANCOVA adjusted for age, sex, education, income, and city). A post hoc Bonferroni test for contrasts showed that this observed difference was mainly due to the higher GPFF Scale scores for Blacks than for Whites. The magnitude of this difference in GPFF Scale scores, determined by adjusted logistic regression analyses, revealed that Blacks were 1.8 times as likely as Whites to have a higher fear of participation in biomedical research. These findings indicate that fear of biomedical research, as measured by the GPFF Scale, was higher among Blacks, when adjusted for age, sex, education, income, and city.
Applying these findings from the LOP Scale and GPFF Scale to the study sample as a whole, we conclude that although Blacks are more likely to report a higher level of fear related to participation in biomedical studies, they are nevertheless just as willing as Whites to participate in biomedical research studies. While Hispanics did not differ from either Blacks or Whites on willingness to participate, Hispanics did report slightly (but not significantly) higher levels of fear related to participation in biomedical studies than Whites, Thus, based on these study findings, the recruitment of Black and Hispanic minorities for biomedical studies appears to be a fully attainable goal for most types of biomedical studies, in addition to being highly desirable for ensuring diversity within study populations in biomedical research.
It is not possible to present a full and direct comparison of the findings from this TLP Study with the findings of the three prior quantitative studies that reported on comparative self-reported willingness to participate in biomedical studies for Blacks and Whites as linked to the USPHS Syphilis Study at Tuskegee. Two of those studies, being tightly focused on the link with knowledge of the original USHPS Syphilis Study at Tuskegee, only reported on the comparative willingness to participate for their subset of respondents who had indicated they had heard of the USPHS Syphilis Study at Tuskegee, but not for all the subjects in their study,29,30
Neither our TLP Study nor the sole remaining quantitative study28
observed statistically significant differences between Blacks and Whites on self-reported willingness to participate as subjects in biomedical studies.
However, given that all three of these quantitative studies did present other findings on distrust of biomedical research (as opposed to willingness to participate) that dearly indicated a higher level of distrust in biomedical research among their Black subjects than among their White subjects, these three quantitative studies are in general agreement with the findings from our TLP Study, which showed that Blacks were statistically significantly higher than Whites on the Guinea Pig Fear Factor (GPFF) Scale (a clear indication of increased distrust) despite not being different on the Likelihood of Participation (LOP) Scale.
In keeping with the above, recently published articles that have directly evaluated actual enrollment rates of minorities into biomedical research studies have found that minorities (largely Blacks and Hispanics) do enroll, proportionally, in clinical research at expected and targeted rates when a reasonable effort is made to enroll them. A report on the enrollment of minorities into the national Women’s Health Initiative Study (WHIS) stated that “the WHI achieved 93% of is targeted minority goal” (p. 342) and noted that “recruitment yields for [Black and Hispanic] minority groups surpassed that of white women” (p. 350).34
A recent review of 20 studies mat reported enrollment rates by race and ethnicity for over 70,000 individuals involving a wide range of biomedical studies (ranging from interview studies to drug treatment and surgical trials) reported that the researchers “found very small differences in the willingness of minorities, most of whom were Blacks and Hispanics in the U.S., to participate in health research compared to non-Hispanic whites” (p. 1) and concluded that “racial and ethnic minorities in the US, are as willing as non-Hispanic whites to participate in health research” (p. 1).36