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 Nutritional Education and the Prevention of Iron Depletion in Children 9 Months to 2 Years (NCT00907088), a randomized na study. The primary outcome is The Primary Outcome is Iron Depletion, and Will be Defined as Serum Ferritin <10 mcg/L..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00907088 |
| Phase | NA |
| Condition | Iron Deficiency |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 251 |
| Arms in the primary outcome | n/a |
| Lead sponsor | The Hospital for Sick Children |
| Results posted | Yes |
2. Clinical Question
Population
Children aged 9 months to 2 years were the target population. The registry record identifies iron deficiency as the condition under study and records enrollment of 251 participants. Further eligibility criteria and participant characteristics are not reported in the registry record.
Intervention
The intervention is named “Healthy milk intake.” The trial rationale proposes that educational encouragement of timely bottle weaning might reduce iron depletion. The registry record does not describe the educational content, delivery, intensity, or adherence.
Comparator
The other intervention is named “Standard nutrition counselling.” The record identifies a control group and an intervention group, but the arm descriptions are blank. The exact counselling received in either group is not reported in the registry record.
Primary question
The primary question is whether the nutritional education approach is associated with a different number of children meeting the registry’s definition of iron depletion at age 24 months. The endpoint is serum ferritin below 10 mcg/L. A result comparing the groups is not reported in the registry record.
3. Trial Design
The registry identifies this as a randomized, quadruple-masked, parallel-group trial. Randomization is a method for assigning participants to groups by chance; in general, it can reduce systematic differences between groups at baseline. The record does not explain how the random sequence was generated, how assignments were concealed, or which people were included in the quadruple masking. Those details are not reported in the registry record.
The named interventions are “Healthy milk intake” and “Standard nutrition counselling.” The record lists a control group and an intervention group, but does not provide descriptions connecting each arm to a particular counselling protocol. It therefore does not establish the precise difference in content between the groups, how counselling was delivered, or whether participants followed the recommendations.
Enrollment is recorded as 251. The trial status is completed. The recorded start is 2006-01, and primary completion is 2009-05. The phase is listed as NA. The sponsor is The Hospital for Sick Children. The registry record does not report the reasons for the enrollment target, recruitment locations, eligibility details, participant flow, follow-up completeness, or baseline characteristics.
The primary outcome is specified at age 24 months and measures the number of participants meeting the stated iron-depletion threshold. The record also lists secondary outcomes for iron deficiency and iron-deficiency anemia. A single group comparison for the primary outcome is not reported in the registry record, so the design information alone cannot establish the direction or magnitude of any difference.
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.
Overall Study
| Stage | Control Group | Intervention Group |
|---|---|---|
| STARTED | 122 | 129 |
| COMPLETED | 102 | 99 |
| NOT COMPLETED | 20 | 30 |
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 | Control Group | Intervention Group | Total |
|---|---|---|---|---|
| Participants analysed | 122 | 129 | 251 | |
| Age, Categorical: <=18 years | Participants | 122 | 129 | 251 |
| Age, Categorical: Between 18 and 65 years | Participants | 0 | 0 | 0 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Sex: Female, Male: Female | Participants | 53 | 66 | 119 |
| Sex: Female, Male: Male | Participants | 69 | 63 | 132 |
| Race/Ethnicity, Customized: White | participants | 85 | 92 | 177 |
| Race/Ethnicity, Customized: Asian | participants | 18 | 12 | 30 |
| Race/Ethnicity, Customized: Hispanic | participants | 13 | 18 | 31 |
| Race/Ethnicity, Customized: Black | participants | 6 | 7 | 13 |
| Bottle use: Breast Only | participants | 46 | 38 | 84 |
| Bottle use: Bottle Only | participants | 60 | 61 | 121 |
| Bottle use: Breast and Bottle | participants | 15 | 26 | 41 |
| Bottle use: Information Not Available | participants | 1 | 4 | 5 |
| Plan to bottle-wean by 2 years old: Plan to Bottle Wean By 2 Years Old | participants | 67 | 63 | 130 |
| Plan to bottle-wean by 2 years old: No Information Available | participants | 55 | 66 | 121 |
6. Primary Endpoint
The registry lists the primary outcome as The Primary Outcome is Iron Depletion, and Will be Defined as Serum Ferritin <10 mcg/L., measured over Age 24 months.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is iron depletion, defined in the registry as serum ferritin below 10 mcg/L, assessed at age 24 months. Ferritin is a blood measure used as an indicator of iron stores. The endpoint is recorded as a number of participants, so the intended outcome is whether a participant meets the threshold rather than the average ferritin value.
As a general statistical concept, converting a continuous measurement into a threshold-based outcome can make a clinically interpretable category available for comparison. It also discards information about how far values lie above or below the cut-off. Participants close to the threshold may be classified differently after small measurement variation, while those well away from it may be less likely to change category for the same amount of variation. These are general properties of threshold-based outcomes, not findings about measurements in this trial.
The registry lists secondary outcomes defining iron deficiency with serum ferritin below 10 mcg/L and MCV below 70 mcm3, and iron-deficiency anemia as hemoglobin below 110 g/L with iron deficiency. The primary endpoint is narrower: it is based on the ferritin threshold. The endpoint definition does not itself show whether either group had more or fewer participants meeting it. A group-level primary outcome comparison is not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record establishes the trial question and the intended primary endpoint, but it does not provide a primary-outcome effect estimate or a group comparison. It states that iron depletion is defined by serum ferritin below 10 mcg/L at age 24 months. The outcome information cannot therefore establish whether the intervention group and control group differed, in which direction a difference might lie, or how precisely a difference was estimated.
The registry notes that the primary outcome has several categories or time points and was not reduced to one comparison. It records 3 outcome measures and 1 analysis, but a usable primary comparison is not reported in the registry record. In the absence of an estimate and its uncertainty, there is no basis for assessing the size of a primary effect, distinguishing a small difference from a large one, or deciding whether an observed difference might be compatible with chance variation.
General statistical interpretation depends on both the estimated effect and its uncertainty. A confidence interval, when reported, describes a range of values reasonably compatible with the data under the statistical model. A narrow interval indicates greater precision than a wide interval; neither width nor coverage can be assessed without an interval. A significance test, when reported, addresses compatibility with a specified null hypothesis under its assumptions. No primary-outcome test result is reported in the registry record.
The trial’s background rationale cites an earlier study of 150 young children aged 12 to 38 months, reporting iron depletion in 37% of bottle-fed children and 18% of cup-fed children, and describing bottle-fed children as almost three times as likely to be iron depleted. Those observations are presented as the rationale for the educational hypothesis. They are not results from the randomized trial and should not be treated as a randomized estimate of the intervention’s effect.
Accordingly, the appropriate reading is limited: the trial was designed to examine an educational approach and iron depletion at age 24 months, but the registry record does not report the primary result needed to estimate the group difference. Completion status indicates that the study is marked completed in the record; it does not substitute for an outcome estimate. The record does not report a confidence interval, a p-value, or enough primary-outcome data to independently calculate an unadjusted comparison.
9. Statistical Methods Explained
What does randomization contribute?
The registry describes the study as randomized. In general, random allocation uses chance to assign participants to trial groups. Its statistical purpose is to reduce the possibility that assignment is systematically related to measured or unmeasured participant characteristics. Randomization does not guarantee that groups will be identical, especially for any one characteristic, and it does not prevent bias from missing outcomes, deviations from assigned interventions, or measurement problems. The sequence-generation and allocation-concealment procedures are not reported in the registry record, so the implementation cannot be assessed.
The study is also described as parallel-group and quadruple-masked. In a parallel design, groups are followed under their assigned trial conditions rather than crossing participants from one condition to another. Masking can, in general, reduce the influence of knowledge about assignment on participant behavior, care, or outcome assessment. The record does not specify which parties were masked or how masking was maintained. It also does not describe whether the endpoint assessor was blinded.
What does the endpoint definition imply?
The primary endpoint is a count of participants meeting a binary threshold: serum ferritin below 10 mcg/L at age 24 months. For a binary outcome, a group comparison can be expressed using quantities such as the difference in event proportions, a relative measure, or a model-based effect. These are general possibilities, not analyses reported for this trial. No group-level primary outcome counts, effect estimate, or uncertainty interval are reported in the registry record, so none of these comparisons can be interpreted for this study.
A threshold converts a laboratory measurement into an event classification. This can make the endpoint easier to relate to a defined state, but it also means that information about the actual measurement values is not retained in the binary count. The registry does not report the distribution of ferritin values, measurement procedures, or whether the primary analysis also considered the continuous measurement.
How should uncertainty be understood?
As a general concept, an estimate from a sample is subject to sampling variation. A confidence interval communicates uncertainty around an estimate under specified assumptions. Its interpretation depends on the model and the data; it is not a guarantee that a true value lies in the interval. A p-value, when used, measures how unusual data at least as incompatible with a null hypothesis would be under that hypothesis and the test assumptions. Neither a p-value nor an interval indicates the clinical importance of an effect on its own.
No confidence interval, p-value, primary-outcome estimate, or statistical model for the primary comparison is reported in the registry record. The record does not report whether the primary comparison was adjusted, whether inference was based on an intention-to-treat population, or how any departures from the planned analysis were handled.
Why can over-dispersion matter?
For count outcomes, general statistical models often rely on assumptions about how variable the counts are. Over-dispersion means the observed variability is greater than a model assumes. If it is ignored, standard errors can be too small and confidence intervals or tests can appear more conclusive than warranted. Whether over-dispersion is relevant depends on the outcome and model. The primary endpoint is described as a number of participants meeting a binary definition, but the registry record does not report a count model or any assessment of over-dispersion.
For a binary participant-level outcome, analyses commonly focus on the probability of meeting the endpoint, with uncertainty that reflects the observed group data and the chosen method. This is a general explanation, not a claim about the analysis used in the trial. The registry record does not provide the group event counts needed to reproduce a comparison.
What can the planning assumptions tell us?
The record describes assumptions for a planning illustration based on the observed effect: a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. Such illustrations can show how hypothetical effect sizes relate to planning under those assumptions. They are not observed trial results, and they do not show the trial’s actual power or establish what effect the trial was designed to detect.
The registry record does not report the trial’s own sample-size justification or the numerical outputs of a planning illustration. The stated assumptions therefore cannot be used to infer the original design rationale. No interim analysis plan, stopping rule, or detailed statistical analysis plan is reported in the registry record. The available methods description is not enough to determine how the sponsor analyzed the primary endpoint.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists a primary outcome and secondary outcomes for iron deficiency and iron-deficiency anemia. It also records 3 outcome measures and 1 analysis. The primary outcome is described as having several categories or time points and is not reduced to one comparison. A single primary-outcome estimate is not reported in the registry record.
Multiplicity arises generally when several outcomes, time points, groups, or statistical tests are examined. Repeated testing can increase the chance of at least one apparently notable result even when no underlying effect exists. Common approaches include designating a primary comparison in advance, adjusting inference, or interpreting secondary analyses as exploratory. Which outcomes or comparisons were prespecified, and whether any multiplicity adjustment was planned or used, are not reported in the registry record.
The record does not report how missing endpoint measurements were handled, how many measurements were unavailable, or whether any imputation method was used. It does not describe the analysis population, including whether all randomized participants were analyzed in their assigned groups. Without participant flow and outcome availability, the effect of missing data on the result cannot be assessed.
These omissions matter because outcome selection, missingness, and analysis-population choices can affect estimates and their uncertainty. The registry record does not report enough information to determine whether the posted analysis followed a prespecified plan or how sensitive conclusions might be to alternative assumptions. This is not evidence that any particular method was or was not used; the relevant details are not reported in the registry 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 |
|---|---|---|---|
| Control Group | 0 | 122 | 0.0% |
| Intervention Group | 0 | 129 | 0.0% |
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 |
|---|---|
| Control Group | 0 of 122 |
| Intervention Group | 0 of 129 |
The registry records serious-event and other-event figures for a control group with 122 participants at risk and an intervention group with 129 participants at risk. It lists 0 affected for both event categories in each group. These are the values recorded in the registry; they should be read as reported counts, not as proof that no event occurred outside the reporting definitions or capture process.
The record does not list serious-event terms, and the death counts are not reported in the registry record. It does not describe the event-collection period, severity criteria, relatedness assessment, or completeness of safety reporting. The at-risk counts do not establish how many participants had complete follow-up for every safety measure.
In general, safety counts are most informative when read with clear definitions, observation periods, and complete follow-up. A zero recorded count can be difficult to interpret if those details are unavailable. The registry record does not report a safety comparison with an uncertainty estimate. These figures therefore do not establish a difference in safety between groups or rule out events that were not captured in the record.
12. What the Result Does, and Does Not, Mean
The available record describes a randomized, quadruple-masked, parallel-group trial of nutritional education in children aged 9 months to 2 years. Its primary endpoint is the number of participants with serum ferritin below 10 mcg/L at age 24 months. This information identifies what the trial sought to assess, but it is not an estimate of the intervention’s effect.
A result does not follow from a hypothesis, a completed status, or the presence of a defined endpoint. The registry record does not report a single primary-outcome comparison, event counts for that endpoint, an effect estimate, or a confidence interval. Consequently, it does not show whether the groups differed, how large any difference was, or how precisely it was estimated. The reported background observations in bottle-fed and cup-fed children belong to an earlier study cited as rationale, not to the randomized trial result.
In general, statistical evidence about an intervention combines an estimated effect with uncertainty and the quality of the design and measurement. Even a precise estimate would need to be interpreted in light of the population, endpoint, intervention content, and analysis. Conversely, a lack of a reported estimate is not evidence that the groups were the same. It means the registry record does not provide the information required to make that comparison.
The record does identify secondary endpoint definitions and registry safety counts. Those details do not fill the gap in the primary outcome result. The safety entries should be interpreted as recorded counts, with the reporting limitations, rather than as a comprehensive demonstration that no safety events occurred.
The defensible conclusion is therefore about the record, not the effectiveness of the intervention: the trial question and outcome definition are available, while the primary comparison and its precision are not reported in the registry record. No conclusion that the intervention did or did not prevent iron depletion can be drawn from these registry entries alone.
13. Why This Trial Matters Statistically
This trial illustrates why a clearly defined endpoint and a reported group comparison are both necessary for statistical interpretation. The registry specifies iron depletion using a laboratory threshold and sets assessment at age 24 months. That definition makes the target outcome identifiable, but without the participant counts or an effect estimate, the endpoint cannot answer whether the randomized groups differed.
It also highlights the distinction between a study rationale and trial evidence. The record cites an earlier comparison of bottle-fed and cup-fed children to motivate an educational hypothesis. An association in a prior study can justify asking a randomized question, but it does not provide the randomized trial’s estimate. Statistical interpretation requires keeping those sources of evidence separate.
The design labels—randomized, quadruple-masked, and parallel—are relevant to how bias may be controlled in general. They do not by themselves show that allocation, masking, outcome measurement, or analysis was implemented successfully. The record’s blank arm descriptions and lack of a primary comparison limit assessment of what participants received and what the trial found.
For biostatistical practice, the case underscores the value of reporting outcome definitions alongside group-level results, uncertainty, participant flow, missing-data handling, and the analysis population. Such information supports evaluation of both precision and potential bias. The registry record contains the intended primary endpoint and some design and safety information, but not the primary result needed to estimate the effect. That distinction is central to transparent interpretation.
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.
A major trial-specific limitation is that the registry record does not report a single primary-outcome comparison. The primary endpoint has a defined ferritin threshold and age of assessment, but no group event counts, effect estimate, confidence interval, or test result are available in the registry record. The direction and precision of the primary outcome therefore cannot be assessed.
The record’s intervention descriptions are limited to the names “Healthy milk intake” and “Standard nutrition counselling.” Arm descriptions are blank. The educational content, delivery, adherence, and exact contrast between the groups are not reported in the registry record. This limits interpretation of what exposure the trial evaluated.
Participant eligibility criteria, baseline characteristics, recruitment details, participant flow, and follow-up completeness are not reported in the registry record. The record does not describe how missing primary-outcome measurements were handled or identify the analysis population. These omissions prevent assessment of the potential effect of incomplete follow-up or analytic choices.
The registry does not report details of random-sequence generation, allocation concealment, masking roles, endpoint measurement procedures, or a full statistical analysis plan. It also does not report whether interim analyses or multiplicity procedures were planned or conducted. These limitations concern what can be established from the registry record; they do not demonstrate that the trial lacked such procedures.
Finally, the registry safety entries show zero affected in the listed categories but do not provide serious-event terms or death counts. The event definitions, observation period, and reporting completeness are not reported in the registry record. Safety interpretation is therefore limited to the recorded figures.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Nutritional Education and the Prevention of Iron Depletion in Children 9 Months to 2 Years — NCT00907088.
- Registry record last updated 2014-04-16; status last verified 2014-03.
- Results first posted 2014-04-16.
- 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
The registry describes NCT00907088, “Nutritional Education and the Prevention of Iron Depletion in Children 9 Months to 2 Years,” as a randomized, quadruple-masked, parallel-group trial. Enrollment is 251; status is completed. The recorded start is 2006-01, and primary completion is 2009-05. The sponsor is The Hospital for Sick Children.
The named interventions are “Healthy milk intake” and “Standard nutrition counselling.” The primary endpoint is the number of participants with serum ferritin below 10 mcg/L at age 24 months. Secondary outcomes address iron deficiency and iron-deficiency anemia. A single primary-outcome comparison and its uncertainty are not reported in the registry record. The record also lists zero affected in the reported serious-event and other-event categories, while death counts are not reported in the registry record.