This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Evaluation and Treatment of Copper/Zinc Imbalance in Children With Autism (NCT00325572), a randomized phase 1 study. The primary outcome is Copper/Zinc Ratio of Children With Autism Compared to Typically Developing Children Phase 2: Change in Copper/Zinc Ratio With Supplementation of Zinc and Vitamin C.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00325572 |
| Phase | Phase 1 |
| Condition | Autism, Pervasive Developmental Disorder |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 89 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Milton S. Hershey Medical Center |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned children with autism, with the description specifying ages 3-8. Its first phase planned to compare serum copper, zinc, and the copper/zinc ratio with values from typically developing children of the same sex and age. The supplementation phase was described for children whose copper/zinc ratios were greater than 2.0 and statistically higher than those of typically developing children. Phase 2 was not initiated, so its planned participant group did not produce outcome data.
Intervention
The planned intervention was oral zinc and vitamin C supplementation for 16 weeks. The arm description says doses were based on the child's weight, with blood measurements and the copper/zinc ratio assessed during follow-up. For children whose ratios had not fallen below 1.25, the description proposed adjusting doses. This is a description of the planned protocol, not evidence that supplementation was administered in phase 2.
Comparator
The planned phase 2 comparator was oral placebo, with liquid volume based on the child's weight to match the intervention group. The study is recorded as randomized, quadruple-masked, and parallel. Details of the randomization sequence, allocation concealment, and which roles were masked are not reported in the registry record.
Primary question
The primary outcome title combines a comparison of copper/zinc ratios between children with autism and typically developing children with a phase 2 question about change in the ratio after zinc and vitamin C supplementation. The record states that phase 2 was not initiated and that no data were collected. Therefore, the intended supplementation comparison cannot be answered from posted phase 2 outcome data.
3. Trial Design
The registry describes a randomized, quadruple-masked, parallel study with a planned enrollment of 89. It lists the study as phase 1 and records the status as terminated. The study description has two phases, but the posted primary outcome states that phase 2 was not initiated and that no data were collected. The record therefore sets out a planned design without reporting outcome results for the supplementation phase.
The first phase was intended to examine serum copper, serum zinc, and the copper/zinc ratio in children with autism, comparing these measures with those from typically developing children matched by sex and age. The second phase was planned as a placebo-controlled supplementation trial. Children with autism meeting the described copper/zinc ratio criterion would receive oral zinc and vitamin C or oral placebo. The planned supplementation period was 16 weeks.
The intervention description says supplementation doses would be based on weight and that blood levels and the copper/zinc ratio would be measured during the trial. It also describes possible dose adjustment for participants whose ratios had not fallen below 1.25. These details describe the intended procedures; they do not establish that the procedures or planned assessments occurred.
The registry does not report the randomization sequence, allocation concealment procedures, the specific roles covered by quadruple masking, or whether masking was maintained. It does not report phase-specific enrollment, participant flow, or the number who completed any planned assessment. The posted enrollment and safety-group counts should not be read as evidence that the phase 2 comparison was carried out, particularly because the primary outcome record explicitly says it was not initiated.
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.
Before assignment: The Modified Checklist for Autism in Toddlers and the Social Responsiveness Scale were used as screens. 3 children were excluded from the comparison group because of scores outside the typical range. 4 children were excluded from the autism study group because they failed to meet criteria for autism using the Autism Diagnostic Interview-Revised.
PHASE I
| Stage | Zinc and Vitamin C Supplementation | Placebo Group |
|---|---|---|
| STARTED | 45 | 44 |
| COMPLETED | 45 | 44 |
| NOT COMPLETED | 0 | 0 |
PHASE ii
| Stage | Zinc and Vitamin C Supplementation | Placebo Group |
|---|---|---|
| STARTED | 0 | 0 |
| COMPLETED | 0 | 0 |
| NOT COMPLETED | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: Phase 2 was not initiated; no data was collected.
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.
| Characteristic | Unit | Zinc and Vitamin C Supplementation | Placebo Group | Total |
|---|---|---|---|---|
| Participants analysed | 45 | 44 | 89 | |
| Age, Categorical: <=18 years | Participants | 45 | 44 | 89 |
| Age, Categorical: Between 18 and 65 years | Participants | 0 | 0 | 0 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Age, Continuous | years | 4.5 (SD 1.2) | 5.9 (SD 1.9) | 5.12 (SD 1.6) |
| Sex: Female, Male: Female | Participants | 4 | 21 | 25 |
| Sex: Female, Male: Male | Participants | 41 | 23 | 64 |
| Region of Enrollment: United States | participants | 45 | 44 | 89 |
6. Primary Endpoint
The registry lists the primary outcome as Copper/Zinc Ratio of Children With Autism Compared to Typically Developing Children Phase 2: Change in Copper/Zinc Ratio With Supplementation of Zinc and Vitamin C, measured over 16 weeks.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary outcome title refers both to comparing the copper/zinc ratio in children with autism and typically developing children and to change in the ratio after supplementation. The ratio is a measure formed from serum copper and zinc values. In the study description, it was used to characterize the difference between the two populations and was also the biomarker intended to change during the supplementation phase.
As a general statistical matter, a biomarker endpoint can provide a defined measurement for comparing groups or tracking change over time. Its interpretation depends on how it is measured, when assessments occur, and how the analysis handles baseline values and repeated observations. Those details can affect the precision and meaning of an estimated change.
The registry names a 16-week timeframe for the primary outcome, but its description says phase 2 was not initiated and no data were collected. Thus, there is no posted phase 2 estimate of change in the ratio, no reported uncertainty interval, and no result that can establish whether the planned biomarker endpoint changed. The record also does not provide a separate phase 1 numerical result for the comparison with typically developing children. The endpoint's planned purpose is clear from the description, but its observed value and statistical precision are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central interpretive fact is that the planned supplementation phase did not proceed according to the primary outcome record: phase 2 was not initiated, and no data were collected. Consequently, the registry contains no phase 2 estimate of change in the copper/zinc ratio and no comparison of zinc and vitamin C supplementation with placebo for that endpoint. The planned trial question is therefore unanswered by posted phase 2 results.
The primary outcome title also names a comparison of children with autism and typically developing children. However, a title describing an intended comparison is not itself a result. No numerical estimate, measure of variability, confidence interval, or significance test for that comparison is reported in the registry record. It is not possible to infer the size or direction of a difference from the title or from the study hypothesis.
The study is recorded as randomized, quadruple-masked, and parallel, and the planned enrollment is 89. Those design labels describe the intended study structure. They do not substitute for outcome observations or analyses. The registry lists 45 participants at risk in the zinc and vitamin C supplementation group and 44 in the placebo group for the adverse-event entries, but those entries do not supply efficacy outcomes or document completion of the planned phase 2 assessments.
As a general statistical principle, an estimate is most informative when considered alongside its uncertainty and the way it was obtained. A confidence interval, when reported, describes a range of values compatible with the data under the stated method; it does not compensate for an absent endpoint dataset. Here, no phase 2 estimate or interval is reported. Likewise, no hypothesis-test result is available from which to judge the strength of statistical evidence.
The status is terminated, but the reason for termination and the timing of that decision are not reported in the registry record. The record also does not report whether any phase 1 assessments were completed or analyzed. Interpretation should therefore remain limited to the stated design, planned measurements, lack of phase 2 data, and posted safety counts.
9. Statistical Methods Explained
The recorded design is randomized, quadruple-masked, and parallel. In general, randomization uses an assignment process intended to make treatment groups comparable with respect to both measured and unmeasured characteristics, on average. It does not guarantee that groups are identical in a particular study. The registry does not describe the sequence-generation method, allocation concealment, or any stratification or blocking procedures, so those implementation details cannot be assessed.
A parallel design assigns participants to groups that are intended to receive different study conditions, with each participant followed within an assigned group. In this study, the planned conditions were oral zinc and vitamin C supplementation and oral placebo. The placebo liquid was described as being matched by volume based on the child's weight. The record does not report the actual administration of these conditions in phase 2, because the primary outcome description says that phase was not initiated.
Masking is intended to limit the influence of expectations or knowledge of assignment on study conduct, outcome assessment, and interpretation. The registry uses the label quadruple-masked but does not identify which people or roles were masked or how masking was maintained. The study summary calls the planned comparison placebo-controlled and double blind, while the design field records quadruple masking. The precise operational meaning of the masking label is not reported in the registry record.
What can be learned from the endpoint record?
The primary outcome title includes a comparison of copper/zinc ratios between children with autism and typically developing children, as well as change in the ratio with supplementation. The outcome description and population both state that phase 2 was not initiated and no data were collected. No statistical estimate, standard error, confidence interval, or p-value is reported for the planned phase 2 outcome. No separate analyzed estimate for the phase 1 comparison is reported either.
As a general statistical explanation, a treatment-effect estimate would describe the observed contrast between intervention groups for a defined outcome and timepoint. Its uncertainty would depend on the amount and variability of observed data and on the analysis method. When the relevant observations were not collected, such an estimate cannot be calculated from the registry record. A planned endpoint and an analysis result are distinct: the former identifies what researchers intended to measure, while the latter requires collected observations and a stated analysis.
How should change and repeated measurements be understood?
The arm description mentions measurements before supplementation, at the midpoint, and at the end, and gives copper/zinc ratio assessments at 6 and 16 weeks. These are planned assessment details in the study summary and arm description. They do not establish that measurements occurred. As a general matter, repeated measurements can describe how an outcome changes over time, but the analysis must account for the relationship between observations from the same participant. A change score, an endpoint comparison adjusted for baseline, and a model using all repeated observations can answer related but not identical statistical questions.
The registry does not state which approach was planned for the endpoint, whether baseline adjustment was intended, or how observations at different times would be combined. It does not report an analysis population, a missing-data method, or a statistical model. No particular method should therefore be attributed to this study beyond the design labels and planned measurement schedule that are recorded.
What do significance tests and intervals contribute?
In general, a significance test evaluates how compatible observed data are with a specified null hypothesis under its assumptions. A p-value is not the probability that a hypothesis is true, nor does it measure the size or practical importance of an effect. A confidence interval gives information about estimation uncertainty and the range of values compatible with the data and method. Both require an estimate based on observed data. Neither is reported for the primary outcome in this record.
The study description says that children in the planned supplementation phase would be enrolled based on ratios greater than 2.0 and that dose adjustment was contemplated if ratios had not fallen below 1.25. These are protocol criteria, not observed findings. A threshold can define eligibility or guide a planned procedure, but it does not show that participants crossed the threshold or that a group-level change occurred.
What statistical plan is available?
The registry record does not report a detailed statistical analysis plan, sample-size justification, interim analyses, covariate adjustment, handling of multiple outcomes, or prespecified contrasts. Without these details and without phase 2 data, statistical significance, effect magnitude, and precision cannot be evaluated for supplementation. General principles about randomization, masking, endpoint analysis, and uncertainty explain how a trial of this kind might be interpreted, but they do not fill gaps in the study's reported methods or results.
10. Multiplicity, Missing Data and Analysis Populations
The study description includes multiple measurements and domains: serum copper, zinc, unbound copper, the copper/zinc ratio, language skills, and a variety of behaviors. The primary outcome title itself refers to a population comparison as well as a supplementation-related change. When a study evaluates multiple outcomes, timepoints, or contrasts, multiplicity can affect how statistical evidence is interpreted. As a general matter, a statistical plan may specify a primary contrast or use an adjustment strategy, but no such strategy is reported in the registry record.
The posted primary outcome says phase 2 was not initiated and no data were collected. No outcome-level analysis is reported, so the record does not describe participant-level missingness within a completed phase 2 analysis. It also does not report a missing-data approach, imputation method, sensitivity analysis, or handling of withdrawals. Whether planned measurements were unavailable for any other reason is not reported in the registry record.
The registry does not identify an intention-to-treat, per-protocol, or other analysis population. It does not give participant flow, numbers assessed at each planned timepoint, or reasons for nonparticipation or discontinuation. The listed adverse-event group counts do not define an efficacy analysis population. Because the relevant phase 2 data and analytic details are absent, neither the consequences of missing observations nor the control of multiplicity can be assessed from the posted record.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Zinc and Vitamin C Supplementation | 0 | 45 | 0.0% |
| Placebo Group | 0 | 44 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Zinc and Vitamin C Supplementation | 0 of 45 |
| Placebo Group | 0 of 44 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Zinc and Vitamin C Supplementation | 0 of 45 |
| Placebo Group | 0 of 44 |
The registry lists two safety groups: Zinc and Vitamin C Supplementation and Placebo Group. The first has 45 participants at risk and the second has 44 participants at risk. For each group, the posted counts are 0 for participants affected by serious adverse events, 0 for participants affected by other adverse events, and 0 deaths.
These entries describe what the registry reports; they do not by themselves establish the completeness of event collection, the duration of safety follow-up, or whether every listed participant received the planned intervention. The primary outcome record states that phase 2 was not initiated and no data were collected, while the safety entries list group counts. The record does not explain the relationship between those entries and the phase 2 status.
As a general statistical matter, a zero recorded count means no events were entered for that category in the stated group; it does not prove that the risk is zero. Interpretation depends on the number actually observed, the way events were defined and collected, and the length and completeness of follow-up. Those details are not reported in the registry record, so the posted counts should be read narrowly as registry entries rather than as a complete characterization of safety.
12. What the Result Does, and Does Not, Mean
The record establishes that investigators planned a study of copper and zinc measures in children with autism, with a proposed randomized comparison of zinc and vitamin C supplementation against placebo. It also documents a planned comparison with typically developing children and describes biomarker and behavioral assessments. These are aims and procedures, not evidence of a measured treatment effect.
For the supplementation question, the key limitation is explicit: phase 2 was not initiated and no data were collected. There is consequently no reported estimate of change in copper/zinc ratio, no group contrast, and no statistical uncertainty for that comparison. The registry does not establish whether supplementation altered the ratio or any selected symptom. The absence of a posted result is not evidence for or against a treatment effect.
The record likewise does not provide a numerical result for the comparison of children with autism and typically developing children. Although the study description states a hypothesis about a difference in the copper/zinc ratio, a hypothesis is not an observed finding. The direction, magnitude, and precision of any phase 1 comparison are not reported in the registry record.
The listed safety counts record zero affected participants for serious and other adverse events and zero deaths in each of the two groups, with 45 and 44 participants at risk, respectively. These entries should be interpreted within the limits of the registry's reporting and the lack of detail about follow-up and event ascertainment.
In short, the record is informative about the intended research question, broad design, planned measurements, status, and recorded safety counts. It does not support conclusions about efficacy, biomarker change, symptom change, or the statistical strength of a treatment comparison. Such conclusions would require observed outcome data and analysis details that are not reported in the registry record.
13. Why This Trial Matters Statistically
This record illustrates an important distinction in clinical-trial statistics: a detailed research question and a randomized design do not themselves produce an estimate of an intervention effect. A study can specify its population, comparator, planned duration, and biomarker while still lacking the observations needed to answer its primary question. Here, the registry states that phase 2 was not initiated and no data were collected.
The trial description also shows why a primary outcome needs to be interpreted in context. The title combines a comparison between children with autism and typically developing children with a planned supplementation-related change in copper/zinc ratio. These are different questions: one concerns a population comparison, while the other concerns change under an intervention relative to a comparator. The record does not provide analyses for either question.
From a statistical perspective, the distinction between protocol criteria and findings is also central. Ratios greater than 2.0 and the 1.25 threshold appear in the planned enrollment and dose-adjustment descriptions. They should not be mistaken for observed participant values or evidence that the ratio changed. Similarly, the randomized, quadruple-masked design label conveys intended structure, but does not demonstrate that the planned phase 2 comparison occurred.
The posted record therefore offers a useful example of how to read trial registrations and results cautiously. Design features describe how evidence was intended to be generated; outcome data and analysis are needed to quantify what happened. When those are absent, statistical interpretation must stop short of effect claims and remain focused on what the record documents and what it leaves unresolved.
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 consequential limitation is that phase 2 was not initiated and no data were collected, as stated in the primary outcome record. This prevents estimation of the planned supplementation effect on copper/zinc ratio and leaves the intended placebo comparison without posted outcome data. The reason for termination is not reported in the registry record, so the circumstances behind the incomplete study cannot be evaluated.
The registry does not report numerical phase 1 results for serum copper, zinc, or copper/zinc ratio, despite describing a planned comparison with typically developing children. Nor does it report numerical results for language skills or behavioral assessments. There are no reported estimates, measures of uncertainty, or statistical tests for these outcomes.
Methods details needed to evaluate potential bias and precision are also absent. The randomization procedure, allocation concealment, the people covered by masking, analysis populations, statistical analysis plan, missing-data procedures, and multiplicity strategy are not reported in the registry record. Participant flow and completion at each planned assessment are likewise not reported.
The safety entries list at-risk counts and zero affected participants or deaths, but the record does not describe event definitions, ascertainment procedures, follow-up completeness, or the relationship between these entries and the statement that phase 2 was not initiated. These limitations constrain what can be inferred from the safety counts. Overall, the registry supports a description of the planned study and its status, but not an assessment of treatment outcomes or their statistical precision.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Evaluation and Treatment of Copper/Zinc Imbalance in Children With Autism — NCT00325572.
- Registry record last updated 2019-07-17; status last verified 2019-05.
- Results first posted 2019-07-17.
- 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.
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18. Record Summary
NCT00325572 is recorded as a phase 1, randomized, quadruple-masked, parallel study with planned enrollment of 89 and status terminated. The study description outlines a comparison of copper and zinc measures in children with autism and typically developing children, followed by a planned 16-week zinc and vitamin C supplementation comparison against placebo.
The primary outcome title refers to both the population comparison and change in copper/zinc ratio with supplementation. The primary outcome description states that phase 2 was not initiated and no data were collected. Numerical efficacy results and analysis details are not reported in the registry record.
Safety entries list 45 participants at risk in the supplementation group and 44 in the placebo group, with 0 affected by serious adverse events, 0 affected by other adverse events, and 0 deaths in each group. The record does not explain the reason for termination or provide further detail on safety follow-up.