Impaired Regulation of Energy Balance in Elderly People (Balance Study): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Impaired Regulation of Energy Balance in Elderly People (Balance Study) (NCT00561145), a non-randomized na study. The primary outcome is Energy Intake Compensation.

2. Clinical Question

The study’s stated first objective was to provide further evidence about whether energy-balance regulation is impaired with age. Its second objective was to investigate physiological mechanisms underlying an age-related failure to regulate energy intake, if the first objective supported that possibility. The registry lists secondary outcome areas involving appetite and satiety, gastrointestinal function, resting energy expenditure, body composition, body weight and gene expression related to energy metabolism.

3. Trial Design

The Balance Study is a completed, non-randomized, parallel-group study sponsored by Wageningen University. The registry lists enrollment of 32 and describes two groups: young men and elderly men. Both groups had an energy restriction period, followed by an ad libitum phase in which energy intake was assessed. Allocation was non-randomized and masking was listed as none. The record lists the phase as not applicable.

The primary comparison is between age groups, rather than between randomized intervention assignments. Because age group was not assigned at random, the groups cannot be assumed to be comparable in all respects other than age. Differences in energy intake could reflect age as well as other differences between participants or aspects of study conduct. The registry itself cautions that the arms are not a like-for-like control comparison.

The study began in 2007-10, had a primary completion date of 2010-03 and is marked completed. The primary endpoint was average energy intake during the ad libitum phase after energy restriction. The record describes this phase as lasting 9 days and expresses average intake in MJ/day. The listed secondary outcome areas cover appetite and satiety hormones and questionnaires, gastrointestinal function, resting energy expenditure, body composition and body weight, and expression of genes involved in energy metabolism.

Further design details—including eligibility rules, age thresholds, the exact conduct of the restriction period, follow-up procedures and the statistical analysis plan—are not reported in the registry record. The registry’s description of the primary outcome population refers to completed participants and a publication, but does not state the analysis population size or provide a linked numerical primary result.

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

Analysis population for the primary outcome, as defined in the registry: completed (see publication)

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 Energy Intake Compensation, measured over Average intake of energy during ad lib phase (9 days).

The primary endpoint, energy intake compensation, is a continuous measure of average energy intake during the ad libitum food-intake phase after energy restriction. It is expressed in MJ/day. The registry describes calculating it from total energy intake across the 9-day ad libitum phase and dividing by the length of that phase. The endpoint is then compared between young men and elderly men.

This measure addresses the study’s question about intake following a period of restriction: it describes how much energy participants consumed, on average, when food intake was ad libitum. It therefore gives a quantitative measure relevant to the stated objective of examining energy-balance regulation. It does not, by itself, establish why any group difference might occur or isolate age from other characteristics that differ between the groups.

The registry identifies the endpoint, unit, summary measure and measurement timeframe, but does not report group means, a difference between groups, an uncertainty interval or a p-value. Consequently, the magnitude and precision of the observed comparison cannot be assessed from the registry record. The exact protocol details for the restriction period and the analysis of the endpoint are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a continuous primary outcome summarized as a mean: average energy intake in MJ/day during the ad libitum phase after energy restriction. The primary comparison is between young men and elderly men. The record gives the endpoint definition and measurement period, but does not report the numerical group summaries or the method used to estimate or test the group contrast.

What a mean describes

General statistical explanation: A mean is a measure of the center of a set of numerical observations. In this study, a group mean would describe average energy intake among the participants included in that group’s endpoint analysis. A mean alone does not show how widely individual values vary. The registry specifies standard deviation as the dispersion measure associated with the primary outcome, but does not report the group means or standard deviations.

What a confidence interval would add

General statistical explanation: A confidence interval expresses uncertainty around an estimated quantity, such as a difference between group means. Its width reflects both the variability in the data and the amount of information available under the analysis. A narrow interval indicates greater precision than a wide interval, but interpretation also depends on the size and meaning of the estimate. No confidence interval for the primary comparison is reported in the registry record, so its precision cannot be evaluated.

What a p-value can and cannot say

General statistical explanation: A p-value summarizes how compatible the observed data are with a specified statistical null model, under the assumptions of the test. It does not measure the probability that the null hypothesis is true, the size of an effect, or its practical importance. The registry record does not report a p-value or identify a statistical test for the primary comparison. No claim about statistical significance can be made from the record.

Why the design matters

General statistical explanation: Random allocation can help balance measured and unmeasured participant characteristics between assigned groups. In a non-randomized comparison, this protection is absent. Here the groups are young men and elderly men, and the registry states that allocation was non-randomized. Any observed difference could be related to age, but the design alone cannot rule out other group differences as explanations. The comparison should not be read as a randomized estimate of an intervention effect.

The registry lists a parallel model, which describes groups followed in parallel rather than a crossover structure. Both listed groups underwent the energy restriction period. The record does not report a separate untreated or randomized control group. It also does not provide the protocol detail needed to assess whether the restriction procedure was identical for all participants or how adherence was assessed.

Why variability matters

General statistical explanation: A standard deviation describes spread among individual observations around a group mean. Greater spread can make a mean difference harder to estimate precisely, particularly when the number of observations is limited. A standard deviation is not the same as a confidence interval: the former describes participant-level variability, while the latter describes uncertainty in an estimated quantity. Although the primary outcome lists standard deviation as its dispersion measure, no observed standard deviations are reported in the registry record.

Planning calculations versus observed findings

General statistical explanation: A sample-size calculation is a planning exercise that asks how many participants would be needed under specified assumptions to detect a chosen effect with a chosen statistical procedure. It is not an observed finding and does not establish that the study had a particular probability of obtaining a significant result. The registry describes a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation and a normal approximation. It says that the target effect is a stated fraction of the observed effect and that non-time-to-event results are expressed as participants per arm. These are planning assumptions, not evidence about the trial’s original design or its observed outcome. The registry record does not report the trial’s own sample-size justification.

Over-dispersion can matter in analyses of count data when variability exceeds what a simple model assumes. General statistical explanation: In that setting, a model that accounts for the extra variability can produce more appropriate uncertainty estimates. The primary endpoint in this study is a continuous mean, not a count outcome, and the registry does not report an analysis model for it. There is no basis in the record to say whether over-dispersion was considered in any analysis.

Finally, the registry records enrollment of 32, but does not provide the endpoint analysis count, the numerical outcome summaries, or the inferential results. Without those elements, statistical interpretation is limited to explaining the endpoint and design rather than evaluating an estimated effect.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Young Men", "Elderly Men")
n   <- c(15, 17)
m   <- c(1, 1)
sp  <- c(1, 1)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Young Men  15  1.000  1.000  0.446  1.554
CARM  Elderly Men  17  1.000  1.000  0.486  1.514

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome, energy intake compensation, and several secondary outcome areas: appetite and satiety hormones and questionnaires, gastrointestinal function, resting energy expenditure, body composition and body weight, and gene expression involved in energy metabolism. It does not report a statistical analysis plan, a hierarchy of hypotheses, or a multiplicity adjustment. Whether and how multiple outcomes or comparisons were accounted for is not reported in the registry record.

Multiplicity matters when several outcomes or statistical tests are considered. General statistical explanation: Examining many results can increase the chance that at least one appears notable by chance, depending on the analysis and interpretation. Adjustment strategies or a prespecified hierarchy can help address that issue, but their use cannot be assumed. The registry record does not identify any such approach.

The record reports enrollment of 32 and describes the primary population as completed participants, with a reference to a publication. It does not state how many participants had usable primary endpoint measurements, whether any data were missing, why measurements might be missing, or how missing values were handled. It also does not report an intention-to-treat, per-protocol or other analysis population definition. These details are not reported in the registry record.

The registry lists no analyses and does not include numerical primary or secondary outcome results. As a result, it is not possible to assess the number of analyses actually conducted, the handling of missing data, or the extent to which reported findings may depend on analysis choices. Those omissions should be distinguished from evidence that no analyses or missing data existed.

12. Safety Results

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

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry reports 0 serious adverse events among 15 young men and 0 among 17 elderly men. It also reports 0 other adverse events among 15 young men and 0 among 17 elderly men. These figures describe the events recorded for the listed groups; they do not establish that no adverse experiences of any kind occurred or that every participant was observed for the same period.

Deaths are listed as null for both groups, so death counts are not reported in the registry record. No serious adverse event terms are listed. The record does not describe how adverse events were defined, how they were collected, the observation period for safety reporting, or whether all enrolled participants were included in these safety counts.

General statistical explanation: A zero recorded event count is a description of what was reported, not proof that the underlying risk is zero. Rare events can remain uncertain when the observed count is zero, and interpretation also depends on the completeness and duration of event monitoring. The registry’s counts should therefore be read as reported event figures, not as a guarantee of absence of harm.

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

The registry record describes a study of energy intake after energy restriction in young men and elderly men. Its primary endpoint is average intake during a 9-day ad libitum phase, expressed in MJ/day. The design is non-randomized, and both age groups underwent the energy restriction period. This provides the context needed to understand the question, but the record does not report the primary result.

Without group means, an estimated contrast, or an uncertainty interval, the registry does not show whether the groups differed, how large any difference was, or how precisely it was estimated. The absence of numerical findings in the record cannot be interpreted as a null result. It also cannot support a conclusion that the study confirmed or disproved impaired energy-balance regulation.

Even with numerical group results, the non-randomized age-group comparison would require cautious interpretation. The design does not make the groups interchangeable, and the registry itself notes that the arms are not a like-for-like control comparison. An observed difference could be associated with age group without establishing that age alone caused it.

The stated aim of investigating physiological mechanisms is broader than the primary endpoint. The registry lists secondary areas relevant to appetite, gastrointestinal function, energy expenditure, body composition, body weight and gene expression, but does not report their numerical findings. Neither the primary nor secondary results can be evaluated from the registry record.

The record reports zero serious and zero other adverse events in the listed groups, while deaths are not reported. Those entries should be understood as registry-reported counts, with the event definitions and monitoring details not reported in the registry record. Overall, the record supports a description of the research question, design and registered outcome measures, but not an assessment of the trial’s numerical findings.

14. Why This Trial Matters Statistically

Statistically, the Balance Study illustrates the difference between defining a research question and reporting evidence that answers it. The registry specifies a continuous primary endpoint, its unit, the measurement phase and the age-group comparison. Those details make the intended outcome understandable. However, without group summaries and an estimate of the contrast, readers cannot assess the size or precision of the observed result.

The non-randomized design is also central to interpretation. A comparison between young men and elderly men can describe differences between those groups, but it is not equivalent to a randomized comparison of assigned treatments. The registry explicitly warns that the groups are not a like-for-like control comparison. That design feature limits causal interpretation regardless of whether a statistical test was used.

The record also highlights why analysis-population and missing-data details matter. Enrollment is reported, and the primary population is described as completed participants, but the number contributing endpoint data and the handling of missing observations are not reported in the registry record. Those details are important for understanding what population an estimate would represent and how complete the evidence is.

Finally, the study’s stated objectives connect a measurable intake outcome to a broader physiological question. The endpoint is relevant to that question, but one outcome alone cannot establish the mechanisms behind any group difference. The absence of numerical primary and secondary results means that the registry record supports methodological description, not a conclusion about the observed association or its underlying explanation.

15. 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.

Several trial-specific limitations affect interpretation. The study is non-randomized, and the comparison is between young men and elderly men rather than randomized assignments. The registry explicitly notes that the arms are not a like-for-like control comparison. Any difference between groups could therefore reflect characteristics beyond age, and the record does not report adjusted estimates or other methods intended to address such differences.

The endpoint focuses on average energy intake during the ad libitum phase after energy restriction. The registry describes this as a 9-day measurement, but does not provide details about the restriction period, food-intake measurement procedures, adherence, or the conditions under which intake was assessed. These protocol details are not reported in the registry record.

The numerical primary result, group-level dispersion, uncertainty interval and p-value are not reported in the registry record. The number of participants with primary endpoint data and the handling of missing observations are also not reported. Although enrollment is listed as 32, the endpoint analysis population cannot be determined from the registry entry.

The registry lists multiple secondary outcome areas but does not report their numerical results or describe how multiplicity was addressed. Its primary population description refers to completed participants and a publication, but the registry record does not provide the analysis details needed to resolve these gaps. The reported safety counts lack event-definition and monitoring details, and deaths are not reported.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Impaired Regulation of Energy Balance in Elderly People (Balance Study) — NCT00561145.
• Registry record last updated 2016-03-11; status last verified 2016-02.
• Results first posted 2016-03-11.
• 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.

19. Record Summary

The Balance Study (NCT00561145) is listed as completed and sponsored by Wageningen University, with enrollment of 32. It was a non-randomized, unmasked, parallel-group study of young men and elderly men; both groups underwent an energy restriction period. The primary outcome was energy intake compensation, defined as average energy intake in MJ/day during the 9-day ad libitum phase after restriction.

The registry states that the study aimed to examine age-related energy-balance regulation and, conditionally, underlying physiological mechanisms. It lists secondary outcome areas related to appetite and satiety, gastrointestinal function, energy expenditure, body composition, body weight and gene expression. Numerical primary and secondary results, the endpoint analysis population and the statistical analysis plan are not reported in the registry record. The listed adverse-event counts are zero for serious and other events in both groups; deaths are not reported.