The Impact of a Parenting Intervention on Latino Youth Health Behaviors: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for The Impact of a Parenting Intervention on Latino Youth Health Behaviors (NCT03517111), a randomized na study. The primary outcome is Adolescent Recent Alcohol Intake Frequency.

2. Clinical Question

3. Trial Design

This was a randomized, parallel-group study with no masking listed in the registry record. The three behavioral programs were a nutrition and substance-use prevention intervention, a substance-use prevention intervention without the nutrition component, and an academic-success comparison program. The registry describes participants as pairs of seventh-grade students and one parent. Only parents attended intervention sessions, while data were collected from both the parent and student.

The listed enrollment was 844. The record gives a start date of 2018-09-26 and a primary completion date of 2022-03-31, and lists the study status as terminated. It does not explain the reason for termination, or report whether enrollment or follow-up ended as planned. The phase is listed as NA.

The study’s stated purpose was to examine whether a parenting program could address substance-use prevention alongside healthy eating. Its stated hypotheses anticipated improved nutrition habits with the nutrition-enhanced program and lower substance-use rates in both parenting programs than in the academic-success program. These are hypotheses, not results. The registry record does not report an analyzed comparison that tests them.

The record lists 41 outcome measures, including measures related to body size, blood pressure, cholesterol, HbA1c, and diet. It lists zero analyses. Randomization identifies the intended study design, but without reported group estimates and analysis details, the design description alone cannot show the size or precision of any intervention effect.

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.

Enrolled

Reasons for not completing this period:

T1 Survey (Week 0)

T2 Survey (Week 10-12)

Reasons for not completing this period:

T3 Survey (Weeks 24-26)

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Only adolescent participants were included in the analysis

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.

6. Primary Endpoint

The registry lists the primary outcome as Adolescent Recent Alcohol Intake Frequency, measured over (T1) Week 0, (T2) Week 10-12, (T3) Week 24-26.

The primary endpoint is adolescent recent alcohol intake frequency. Students were asked how many times in the past 30 days they had drunk more than a sip of beer, wine, or liquor. The response scale assigns ordered scores from 0, meaning 0 times, through 6, meaning 40 or more times. Intermediate categories distinguish increasing frequency. The registry describes the measure as a mean with standard deviation and gives measurements at (T1) Week 0, (T2) Week 10-12, and (T3) Week 24-26.

This endpoint was chosen to assess a substance-use behavior relevant to the study’s prevention aim. Measuring it at baseline and follow-up allows investigators, in principle, to examine how reported recent drinking changes over time and whether patterns differ among the randomized programs. However, no group means, standard deviations, changes, confidence intervals, or tests are reported in the registry record. The outcome definition and schedule therefore describe what was intended to be measured; they do not indicate what the students reported or whether the groups differed.

Because the scale uses ordered frequency categories, its values represent coded responses rather than exact counts of drinks or drinking occasions. A mean can summarize scores across participants, but by itself does not describe the full distribution of responses. That distinction matters when interpreting an average for a scale with grouped categories, particularly when the underlying response distributions are not reported.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a randomized, parallel-group design. Randomization is intended to make assigned groups comparable, on average, with respect to measured and unmeasured baseline factors. That benefit depends on implementation and does not guarantee identical groups in a particular study. The record does not report the randomization sequence method, allocation concealment, or allocation ratio, so those details cannot be evaluated.

What does the primary outcome summarize?

The endpoint is a score based on ordered categories of self-reported drinking frequency during the previous 30 days. The registry specifies a mean and standard deviation as the summary measures. A mean provides a compact description of the average coded score; a standard deviation describes dispersion around that mean. General statistical consideration: when an outcome is made from ordered categories, an average may not convey whether responses cluster in a few categories or are spread across them. Category counts or a distributional summary can add context, but those results are not reported in the registry record.

How would the group comparison be interpreted?

In general, a randomized comparison estimates how outcomes differ between assigned groups, subject to missing data, adherence, and analysis choices. For this study, relevant contrasts could involve either parenting program and the academic-success program, or the two parenting programs against one another. The registry record does not identify which pairwise contrasts were analyzed, report any group estimates, or provide an analysis model. It also does not state whether the primary comparison focused on a particular follow-up time or modeled repeated measurements across time.

General statistical consideration: repeated observations from the same student are correlated rather than independent. An analysis using multiple time points should account for that correlation or specify another appropriate approach. The measurement schedule includes baseline and two follow-up windows, but the registry does not report how those repeated observations were handled.

What do significance levels and confidence intervals tell readers?

General statistical explanation: a significance level sets a threshold for a statistical testing procedure; a p-value measures the compatibility of observed data with a specified null hypothesis and model. A confidence interval conveys uncertainty around an estimated effect under the method used. Neither a p-value nor an interval alone establishes whether a difference is important in practice. The registry record does not report a significance level for the trial’s outcome analysis, p-values, effect estimates, or confidence intervals.

The record describes a separate planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is described as a stated fraction of the observed effect. These assumptions describe a planning calculation, not the trial’s own design justification. The record does not report a sample-size justification or the numerical planning results. Such illustrations are not observed power and cannot substitute for the actual outcome estimates or their uncertainty.

Why can over-dispersion matter?

General statistical explanation: over-dispersion occurs when observed variation is greater than a statistical model assumes. If it is ignored, standard errors and tests can be misleading. This concept is relevant to some count or frequency outcomes, but the registry describes this endpoint as a scored scale and does not report a model or diagnose over-dispersion. It would therefore be unwarranted to claim that over-dispersion occurred or affected the results.

For a complete interpretation, readers would need the analyzed sample sizes, group summaries, treatment contrasts, uncertainty estimates, model specification, and account of missing observations. These details are not reported in the registry record. The design and outcome description explain the question and intended measurement, but not the statistical evidence from the trial.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 41 outcome measures, while the primary endpoint has measurements at three scheduled time points. Considering several outcomes, time points, or group contrasts can create a multiplicity issue: the more statistical tests conducted, the greater the chance that at least one result appears notable by chance if each test is interpreted in isolation. General statistical approaches include defining a limited set of primary comparisons in advance or adjusting inference when appropriate. The registry record does not report a multiplicity strategy, a hierarchy among the outcomes, or the comparisons included in an analysis.

The record lists zero analyses and does not report primary-outcome estimates. It also does not report participant counts with outcome data at each time point, reasons for missingness, imputation methods, or sensitivity analyses. Thus, it is not possible to assess whether missing observations could have affected the comparisons.

The primary outcome population is described as adolescent participants only. The registry does not give additional analysis-population definitions, such as whether participants were analyzed according to randomized assignment, whether adherence was required, or how participants without follow-up measurements were handled. These choices can affect the interpretation of a randomized comparison. Their absence from the registry record means the analysis population and missing-data handling remain unclear; it does not establish that any particular method was or was not used outside the record.

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 lists three groups for adverse events: Nutrition/Substance Use Prevention, Substance Use Prevention Only, and Academic Success Program. For each group, the listed number at risk is 361, 222, and 261, respectively. The serious adverse event count is 0 in each group, and the other adverse event count is also 0 in each group. The listed death count is 0 in each group. No serious adverse-event terms are listed.

These entries describe what the registry reports; they are not a comparison of event rates or evidence that no events occurred outside the recorded data. The registry does not explain the event-collection period, definitions, monitoring procedures, or completeness of reporting. It also does not give a narrative account of safety monitoring. A zero count in a registry entry should therefore be read as zero events reported in that entry, not as proof that an intervention is free of risk.

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

The registry record identifies a randomized study of three parenting or educational programs and defines a primary measure of adolescent recent alcohol intake frequency. It also records planned assessments at baseline and two follow-up periods. Those details help clarify the research question and the intended outcome measurement.

The record does not report an analyzed primary-outcome comparison, group means, effect estimates, or uncertainty measures. Therefore, it cannot show whether the outcome differed between programs, how large any difference was, or how precisely a difference was estimated. The investigators’ stated hypotheses are not trial findings. The listed enrollment is not a substitute for outcome results, and the adverse-event counts do not answer the primary research question.

General statistical distinction: absence of a reported analysis is not evidence of no effect, and it is not evidence that an effect exists. A result can only be interpreted in light of the estimate, its uncertainty, the analysis population, and the methods used. Those elements are not reported for the primary endpoint in the registry record.

The study status is listed as terminated, but the reason is not reported in the registry record. That status alone does not establish why the trial ended, whether data collection was complete, or whether a particular result influenced the decision. The responsible interpretation is limited to the documented design, outcomes, enrollment, status, and adverse-event entries. No medical or treatment conclusion follows from those details alone.

13. Why This Trial Matters Statistically

This trial is statistically notable for the structure of its question: it planned to compare two parenting programs with an academic-success program and to measure a behavioral outcome in adolescents over more than one time point. The nutrition-enhanced program also creates a distinct comparison with the substance-use prevention-only program. Those comparisons address different questions, so clear specification of the target contrast is important when interpreting results.

The endpoint is a coded frequency score rather than a direct count of drinks. Reporting its group distributions alongside means would help readers understand how students’ responses were distributed across the ordered categories. Repeated measurement also makes it important to explain how observations from the same student were handled. These are general interpretive considerations; the registry record does not report the outcome analysis or its model.

The registry lists 41 outcome measures, making transparent reporting of the primary comparison and any multiplicity strategy especially relevant. It lists zero analyses and provides no primary-outcome estimate or confidence interval. As a result, the record illustrates a distinction central to clinical statistics: a well-defined question and randomized design do not by themselves provide evidence about the size or precision of an outcome difference. The analysis results and their limitations are necessary to interpret what the trial found.

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 most direct limitation for interpreting this trial record is the absence of reported primary-outcome results. No group summaries, contrasts, confidence intervals, or p-values are listed, and the record lists zero analyses. The planned endpoint and follow-up schedule therefore cannot be connected to a reported estimate of change or difference.

Other analysis details are also not reported in the registry record: the randomization procedure, allocation ratio, group-specific primary-outcome sample sizes, handling of repeated measurements, missing-data methods, and analysis population beyond the statement that only adolescents were included. The reason for the terminated status is not reported. These omissions prevent assessment of attrition, analysis choices, and the potential effect of missing observations.

The outcome is based on self-reported drinking frequency recorded in ordered categories. The registry does not report category-level response distributions or discuss measurement limitations. The listed adverse-event counts are zero, but the event definitions and collection procedures are not described in the record, limiting interpretation of those entries. These limitations describe what is unavailable in the registry record; they do not establish that a particular bias or problem occurred.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: The Impact of a Parenting Intervention on Latino Youth Health Behaviors — NCT03517111.
• Registry record last updated 2024-02-26; status last verified 2024-02.
• Results first posted 2024-02-26.
• 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

The registry record describes a randomized, parallel-group study with no masking listed and three behavioral programs: nutrition and substance-use prevention, substance-use prevention only, and academic success. It lists enrollment of 844, a start date of 2018-09-26, primary completion on 2022-03-31, and a terminated status.

The primary outcome is adolescent recent alcohol intake frequency, measured with a score based on past-30-day response categories at baseline and two follow-up periods. The analysis population is described as adolescents only. The record lists 41 outcome measures and zero analyses; primary-outcome estimates and inferential results are not reported. Each group’s adverse-event entry lists zero serious events, zero other events, and zero deaths.