Racial Discrimination and Stress Response: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Racial Discrimination and Stress Response (NCT05820659), a na na study. The primary outcome is Change in Mean Arterial Pressure for Peer Rejection.

2. Clinical Question

The stated research questions include associations between racial discrimination experiences and stress responses, and examination of parental ethnic-racial socialization, adolescents’ attributions about subtle racism, and racial identity as potential risk or protective factors. These are questions about relationships among experiences, characteristics, and responses; the single-group design does not provide a randomized treatment-versus-control contrast.

The primary outcome concerns change in mean arterial pressure during a peer rejection task. The registry also lists outcomes involving blood pressure, emotional experience, attribution, skin conductance, and respiratory sinus arrhythmia during the puzzle task or the conversation about peer rejection. The registry record describes these planned measurement domains but does not report numerical findings for them. It therefore does not establish whether the anticipated associations were observed or how precisely they were estimated.

3. Trial Design

This is a completed, single-group behavioral study sponsored by Western Kentucky University. The registry lists the condition as acute stress reaction, the study phase as not applicable, allocation as not applicable, and masking as none. Enrollment is 178. The recorded study start is 2023-06-29, and primary completion is 2024-11-17. The registry record does not describe random assignment or a parallel control group; its own design classification is single group.

The behavioral intervention is described as a peer rejection task, a conversation about peer rejection, and an impossible puzzle task. In the task description, adolescents complete an adapted computer task involving peer rejection by White peers, discuss the task with parents, and complete a puzzle intended to elicit cognitive stress. These procedures provide the context for examining responses to task-related experiences. The record does not report detailed task procedures, the order of all measures, or whether every participant completed every procedure.

The primary outcome is change in mean arterial pressure for peer rejection, measured across baseline, during-task, and post-task periods. The timeframe is described as baseline from five minutes before to immediately before the task, during the task from start to end, and after the task from immediately after to 45 minutes after the peer rejection task. The record says diastolic and systolic blood pressure will be continuously monitored. It does not report the numerical outcome summaries or the analysis used to turn those readings into a result.

The registry lists 16 outcome measures and zero analyses. Its status is completed, but completion status alone does not supply outcome results. The sample-size justification and detailed statistical analysis plan are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Impossible Puzzle

Peer Rejection Task

Conversation about Peer Rejection

Analysis population for the primary outcome, as defined in the registry: Only 80 adolescents completed the peer rejection task. One adolescent did not provide any blood pressure readings.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

Population: Adolescents participated in the impossible puzzle task, the peer rejection task, and the peer rejection discussion task. Parents only participated in the peer rejection discussion task.

6. Primary Endpoint

The registry lists the primary outcome as Change in Mean Arterial Pressure for Peer Rejection, measured over baseline (5 minute before to right before the task), during (start to the end of the task), and post-task (right after to 45 minutes after the peer rejection task).

The primary endpoint is titled change in mean arterial pressure for peer rejection and is expressed in mmHg. It is a continuous measure, with the registry identifying the summary parameter as a mean and the dispersion measure as a standard deviation. The outcome is assessed across baseline, during-task, and post-task periods. The stated monitoring procedure is continuous measurement of adolescents’ diastolic and systolic blood pressure.

Blood pressure is a physiological response that can be measured repeatedly around a stressful task. Comparing measurements across the defined periods can describe how the recorded pressure varies in relation to the task and its immediate aftermath. As a general statistical concept, a continuous outcome can be summarized by its mean to describe the central level of measurements and by a standard deviation to describe their spread. Repeated observations can also carry information about within-person patterns, although the registry record does not report the model or calculation used for this endpoint.

The primary endpoint is relevant to the stated question because the study concerns biological responses to a task framed as subtle racial discrimination. But an endpoint definition is not a result: no mean change, standard deviation, confidence interval, or hypothesis-test result for this outcome is reported in the registry record. The available description therefore identifies what was intended to be measured, not the size or precision of any observed response.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry characterizes the primary outcome as continuous, reports the mean as its parameter, and identifies the standard deviation as its dispersion measure. These labels describe possible ways of summarizing the measurements. They do not reveal the actual observed mean or spread, and the registry record does not report those numerical summaries.

What does a mean summarize?

As a general statistical concept, a mean is a measure of the center of a set of quantitative observations. For an outcome measured repeatedly around a task, a mean might summarize values at a particular period or changes defined from measurements at different periods. The interpretation depends on the exact calculation and analysis population. Here, the registry supplies the outcome title and timing but does not specify the calculation used to derive change in mean arterial pressure from the continuously monitored blood-pressure readings. The title alone is not enough to reconstruct that calculation.

What does a standard deviation describe?

In general, a standard deviation describes how dispersed individual observations are around their mean. It is not the same as the uncertainty of the mean: uncertainty also depends on the amount and structure of available data and on the analysis method. With repeated measurements, observations from the same participant are related, so an analysis may need to account for that dependence. The statistical model and the treatment of repeated readings are not reported in the registry record. No standard deviation for the primary outcome is posted.

How should repeated measurement be understood?

The registry defines baseline, during-task, and post-task periods and states that blood pressure is continuously monitored. Repeated measurement can describe a pattern over time rather than a single isolated reading. As a general matter, the choice of summary matters: a period-specific mean, a difference between periods, and a model-based time pattern answer different questions. The registry does not report which of these was used for analysis, the number or timing of usable readings, or how readings within a participant were incorporated. It is not appropriate to infer a method from the endpoint title.

What would a confidence interval add?

In general, a confidence interval expresses the uncertainty around an estimate under a specified statistical method. A narrow interval indicates greater precision than a wide interval, while neither width nor inclusion of a particular value substitutes for judging the estimate’s substantive meaning. A confidence interval for a change in pressure would help readers understand which magnitudes are compatible with the observed data and model. No confidence interval for the primary endpoint is reported in the registry record.

What do the sample-size illustrations represent?

The sample-size illustrations use a two-sided significance level of 0.05, equal allocation between two hypothetical arms, and a normal approximation. They are based on a stated fraction of the observed effect. These are planning assumptions for illustrations, not a report of the study’s original design justification. The registry record does not report the trial’s sample-size justification. Because the actual study is single-group and has no randomized comparison, the two-arm equal-allocation setup is not a description of this study’s design. Such illustrations are not observed power and do not establish how informative the actual study was.

The illustrations also depend on an observed effect, but the registry record does not provide the numerical primary outcome effect needed to interpret a particular illustration. Without the estimate, its uncertainty, and the method used to obtain it, the illustrations cannot replace an analysis of the posted study data. They should be understood as hypothetical planning quantities rather than evidence that the study detected an effect or had a specified probability of doing so.

Finally, a test result, if reported, would address compatibility with a statistical null model under stated assumptions; it would not by itself establish causation or importance. In this record no primary-outcome test result is reported. The methods labels and design information provide useful context, but they cannot fill in unreported estimates, model choices, or analytic decisions.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 16 outcome measures, including the primary blood-pressure outcome and outcomes related to the impossible puzzle and the conversation about peer rejection. Examining multiple outcomes can raise a multiplicity issue: as a general statistical concept, testing many hypotheses can increase the chance of at least one apparently unusual result if each is judged separately. Appropriate interpretation depends on which outcomes were prespecified as primary or secondary, which tests were conducted, and whether any adjustment or hierarchy was used.

The registry record does not report a multiplicity strategy, a detailed statistical analysis plan, or analyses of the listed outcomes. It records zero analyses. The outcome list therefore cannot be treated as evidence that each measure was analyzed, nor can it show whether results were selected or adjusted. The primary outcome is identified, but the registry does not provide its numerical result or a complete analytic hierarchy for the other measures.

Missing data also matter. The primary outcome description states that only 80 adolescents completed the peer rejection task and that one adolescent did not provide any blood-pressure readings. The record does not report why task completion was limited, whether all completed participants contributed readings at all time periods, or how missing observations were handled. It does not state whether an analysis included all enrolled adolescents, only those who completed the task, or another defined population. These analysis-population details are not reported in the registry record.

As a general principle, missingness can affect both precision and the interpretation of estimates, especially if the availability of measurements is related to participant characteristics or responses. The registry provides too little information to assess that possibility. Neither a missing-data method nor sensitivity analyses are reported.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

The registry’s serious adverse event figures list 178 participants at risk and zero affected participants in the stress-inducing and conversation task group. The record also lists 178 participants at risk for other adverse events and zero affected participants. Deaths are recorded as zero, and no serious adverse event terms are listed.

These are registry counts, not an estimate of comparative risk: the study is single-group and does not have a randomized control group for a like-for-like safety comparison. A zero in the posted event fields means that the registry reports no events in those fields; it does not provide information about event definitions, collection procedures, or the completeness of event ascertainment beyond what the record states. Those details are not reported in the registry record.

It is also important not to interpret the adverse-event denominator as the number who completed the primary task. The registry reports enrollment of 178, while the primary outcome note says that only 80 adolescents completed the peer rejection task. The adverse-event fields do not explain how participation or follow-up differed across the study procedures. These counts describe what was entered in the registry and should not be treated as a comparative safety analysis.

12. What the Result Does, and Does Not, Mean

This study addresses a question about how ethnic minority adolescents’ experiences of racial discrimination relate to physiological and other responses in a task setting. Its procedures include a peer rejection task, a conversation about that task with parents, and an impossible puzzle task. The registry identifies potential social and cognitive factors of interest, including parental ethnic-racial socialization, attribution of subtle racism, and racial identity.

The information in the registry record does not establish whether racial discrimination experiences were associated with a particular stress response. It does not report estimates for the primary blood-pressure outcome or results for the other listed measures. It also does not report analyses of the proposed risk and protective factors. Accordingly, the direction, size, and precision of any relationship remain unknown from the posted results.

Even if associations were reported, an association in a single-group task study would not by itself show that one factor caused a physiological response. General interpretation of observational relationships requires attention to study design, measurement, and other factors that may relate to both exposure and outcome. The registry record does not report enough analytic detail to assess those issues or the models used.

The registry’s completed status indicates the study is recorded as completed; it is not a statistical finding. Likewise, enrollment and task-completion counts describe participation, not the magnitude of a response or its scientific importance. The appropriate conclusion from the available record is limited: it defines the study’s research questions and measurements, while leaving the primary outcome and related analyses unreported.

13. Why This Trial Matters Statistically

This study is statistically interesting because it combines a socially meaningful research question with measurements intended to capture responses during and after structured tasks. Continuous blood-pressure monitoring across baseline, task, and post-task periods could support investigation of response patterns, while the listed physiological and self-reported outcomes represent different dimensions of the study’s questions. The registry identifies these measurement aims but does not report their numerical results.

The design also makes careful description especially important. It is a single-group study with no randomized comparison described, so estimates would need to be interpreted according to the actual analyses and the limits of that design. The registry’s title for the primary endpoint, its time windows, and its monitoring description do not fully specify how repeated observations were reduced or modeled. That distinction matters because different analytic choices can answer different questions.

The gap between overall enrollment and the number who completed the peer rejection task is another reason to report analysis populations and missing-data handling clearly. The registry record gives the task-completion note and one missing blood-pressure reading, but does not explain the remaining participation or analysis details. Without these, readers cannot judge how representative the analyzed measurements might be of the enrolled group.

Finally, the outcome list makes transparent that the study addressed several measurement domains, while the record reports no analyses. Reporting outcome-specific estimates, uncertainty, analytic methods, and the handling of multiple outcomes would be necessary for readers to assess the findings. Statistical transparency is central to separating the study’s important questions from conclusions that the posted evidence can support.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The registry record does not report the numerical result for the primary endpoint, its standard deviation, a confidence interval, or a hypothesis-test result. It lists 16 outcome measures but zero analyses. This prevents assessment of the magnitude and precision of the primary response and leaves the listed secondary outcome questions unresolved.

The design is recorded as single group, with allocation not applicable and no masking. The record does not describe a randomized comparison group. This limits the kinds of causal comparisons that can be made from the design as described, and the registry does not report analyses that would clarify the associations under study.

The primary outcome note states that only 80 adolescents completed the peer rejection task and that one adolescent did not provide blood-pressure readings. Reasons for non-completion, the completeness of measurements across time periods, the analysis population, and methods for handling missing data are not reported in the registry record. Without these details, the potential implications of incomplete task or measurement data cannot be evaluated.

The registry identifies mean arterial pressure as the primary endpoint while describing continuous monitoring of diastolic and systolic blood pressure. It does not report the exact calculation used to define change, the model for repeated observations, or the analytic plan for multiple outcomes. Nor does it report the trial’s sample-size justification. The sample-size illustrations use hypothetical two-arm assumptions and should not be mistaken for the actual single-group design or for observed power.

These limitations concern what can be interpreted from the registry record; they do not establish that unreported procedures or analyses were not conducted. They mean that those details and results are not reported in the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Racial Discrimination and Stress Response — NCT05820659.
• Registry record last updated 2026-08-17; status last verified 2026-08.
• Results first posted 2026-08-17.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

NCT05820659, titled Racial Discrimination and Stress Response, is a completed single-group behavioral study sponsored by Western Kentucky University. The registry lists enrollment of 178 and describes a peer rejection task, a conversation about peer rejection, and an impossible puzzle task. The study concerns ethnic minority adolescents’ experiences and stress responses, including potential social and cognitive risk or protective factors.

The primary endpoint is change in mean arterial pressure for peer rejection, assessed across baseline, during-task, and post-task periods. The record says diastolic and systolic blood pressure was continuously monitored. It notes that only 80 adolescents completed the peer rejection task and that one adolescent had no blood-pressure readings.

The registry lists 16 outcome measures and zero analyses. It does not report numerical results for the primary endpoint, analyses of the proposed factors, or a detailed statistical plan. Serious and other adverse event fields each report zero affected participants, and deaths are recorded as zero. The available record describes the study and its intended measurements but does not report the outcome evidence needed to assess its research questions.