Response of Alkylresorcinols to Different Cereals: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Response of Alkylresorcinols to Different Cereals (NCT01287403), a randomized na study. The primary outcome is Plasma Alkylresorcinol Compounds.

2. Clinical Question

The central statistical contrast is between the esterase-treated wholegrain wheat preparation and each other flour. The posted data describe the average response and its variability in each arm, then give estimated mean differences, confidence intervals, and unadjusted p-values for those comparisons. These results can indicate which contrasts are estimated with greater separation from the reference and which remain imprecise. They do not establish a clinical effect: the primary measure is a laboratory biomarker, and clinical outcomes are not reported in the registry record.

3. Trial Design

The registry classifies the study as randomized, quadruple-masked, and crossover, with phase listed as not applicable. Its status is completed. Fourteen participants were enrolled, and the primary-outcome summaries report 13 participants in each intervention arm. The record describes six cereal preparations: refined wheat flour, esterase-treated wholegrain wheat flour, wholegrain wheat flour, liquid wholegrain wheat flour, wholegrain barley flour, and liquid wholegrain barley flour.

A crossover design evaluates interventions within a study structured around participants receiving more than one intervention condition. In general, this can allow comparisons to account for stable differences between people, but the precise benefit depends on how treatment order, timing, and analysis are handled. The registry record does not report the treatment sequence, the interval between preparations, any washout procedures, or how period and carryover effects were addressed. Those details should not be inferred from the crossover label alone.

Refined wheat flour was described as a negative-control flour. Esterase-treated wholegrain wheat flour was described as a positive control for phenolic acids. The other preparations were described as having unknown responses or as test flours. The posted primary comparisons use the esterase-treated preparation as their reference, so the comparison reference differs from the negative-control description attached to refined wheat flour.

The primary measurement covers the period from 0 to 48 h after intake. The posted registry record identifies the sponsor and reports study start and primary completion dates, but those dates do not describe the treatment schedule. Eligibility details beyond healthy status, recruitment methods, masking procedures, allocation procedures, and the trial's original sample-size justification 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.

Before assignment: Thirteen subjects completed the trial, where 100 g of each flour, mixed with 300 mL milk, was fed to all subjects. Subjects avoided foods containing whole grains for one week prior, and 36 h before the start of each treatment, to avoid all phenolic-rich foods (e.g. coffee, tea, chocolate, most fruits and vegetables).

Diet Restriction (7 Days)

1st Intervention (1 Day)

Reasons for not completing this period:

Washout 7 Days

2nd Intervention (1 Day)

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: All subjects were recruited within the staff of the Nestlé Research Center between February and June 2011.

6. Primary Endpoint

The registry lists the primary outcome as Plasma Alkylresorcinol Compounds, measured over From 0 to 48 h post dose..

The primary endpoint is the area under the curve over baseline for plasma alkylresorcinol compounds, expressed in nmol/L*h. The registry record describes measurements from 0 to 48 h after a preparation was consumed, with blood sampling at t = 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 24 and 48 h. An area under the curve combines measurements across a specified time interval into a single summary of the concentration response. “Over baseline” indicates that the response is expressed relative to the baseline level rather than as an isolated post-intake concentration.

Using an integrated measure is generally useful when the scientific question concerns the overall response across time, rather than the value at one selected time point. It also makes a multi-time-point response available for arm-level comparison. The endpoint is a continuous measure; the registry record reports means and standard deviations for each arm. In general, the standard deviation describes how spread out individual measurements are around the arm mean, while the mean describes the average endpoint value.

This endpoint is a biomarker measure, not a direct measure of health or clinical benefit. The registry record names plasma and urinary betaine and phenolic acids as secondary outcomes, but the primary result considered in these comparisons is the plasma alkylresorcinol-compound AUC. Details of how the AUC was calculated, including any interpolation or missing-time-point rules, are not reported in the registry record.

7. Results Posted in the Registry

• Refined Wheat Flour: mean 1,548 versus 19,357 on control; difference -17,809 (95% CI -21,908 to -13,710), standardized effect d = -3.34; z-test p = <0.001.
• Liquid Whole Grain Wheat Flour: mean 17,307 versus 19,357 on control; difference -2,050 (95% CI -7,246 to 3,146), standardized effect d = -0.30; z-test p = 0.439.
• Liquid Wholegrain Barley Flour: mean 5,385 versus 19,357 on control; difference -13,972 (95% CI -18,299 to -9,645), standardized effect d = -2.48; z-test p = <0.001.
• Wholegrain Wheat Flour: mean 17,139 versus 19,357 on control; difference -2,218 (95% CI -7,576 to 3,140), standardized effect d = -0.32; z-test p = 0.417.

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is continuous, and the registry reports its mean and standard deviation within each intervention arm. A mean is the arithmetic average of participant measurements. A standard deviation describes the dispersion of those measurements around the mean; it is not the uncertainty in the mean itself. The sample size helps determine how precisely the mean and contrasts can be estimated, but the registry record does not report participant-level data or the distributions of the endpoint.

What does a mean difference describe?

The comparisons report mean differences between the esterase-treated wholegrain wheat flour reference and each other preparation. A difference is an estimate of how far apart the two arm means are on the endpoint's measurement scale. Negative estimates in the posted comparisons accompany lower means in the non-reference arm than in the reference arm. For example, the refined wheat flour comparison has an estimated mean difference of -17810.0 nmol/L*h, with a confidence interval from -21910.0 to -13710.0. This is an absolute difference on the AUC scale, not a percentage change.

These comparisons are unadjusted recalculations from the posted arm summaries. They are not a substitute for an analysis that uses participant-level observations or the original statistical model. In a crossover design, repeated measurements from the same participant can be correlated. A paired analysis can use that within-person relationship, whereas separate arm means and standard deviations do not reveal the covariance between a participant's responses under different preparations. That covariance and the original analysis approach are not reported in the registry record.

How should the confidence intervals be read?

A confidence interval represents uncertainty around an estimated difference under the assumptions of the method used to construct it. In general, narrower intervals indicate more precise estimates, while wider intervals leave a broader range of plausible differences. For liquid wholegrain wheat flour, the interval is -7246.0 to 3146.0; for wholegrain wheat flour, it is -7576.0 to 3140.0. Both include zero, which corresponds to no mean difference on this scale. The intervals for refined wheat flour, liquid wholegrain barley flour, and wholegrain barley flour are entirely negative. An interval's relation to zero is informative about statistical compatibility, but it does not by itself establish clinical importance.

The posted p-values are unadjusted: <0.001 for refined wheat flour, liquid wholegrain barley flour, and wholegrain barley flour; 0.439 for liquid wholegrain wheat flour; and 0.417 for wholegrain wheat flour. In general, a p-value is calculated under a null hypothesis and a set of model assumptions. A small p-value indicates that the observed data would be relatively unusual under that null model; it does not quantify the size or importance of an effect. Because the registry record does not report the original analysis plan, the posted p-values should not be treated as a complete account of the trial's planned inferential approach.

Why does the crossover structure matter?

In general, crossover studies can compare treatment responses within participants, which may reduce the influence of stable between-person differences. That advantage depends on an appropriate design and analysis. Treatment order, period effects, carryover, and the time between exposures can influence a crossover result. The registry record does not report how these issues were managed or modeled. Consequently, the arm means and unadjusted recalculations cannot show whether any crossover-specific features were included in the sponsor's analysis.

Over-dispersion, in general, means that observed variability is greater than a model assumes. If a model understates variability, standard errors can be too small and intervals can be too narrow. The posted summaries include standard deviations, but the registry record does not describe a distributional assessment or report a model for extra variability. It is therefore not possible to assess from the registry record whether over-dispersion was considered.

What is and is not reported about the analysis?

The registry record reports the primary measure, its unit, the time window, arm means, standard deviations, sample sizes, estimated mean differences, confidence intervals, and unadjusted p-values. It also identifies two secondary-outcome topics: plasma and urinary betaine, and phenolic acids. The record does not report the original statistical analysis plan, a model specification, the treatment of period or sequence, an analysis population definition, or rules for missing measurements. The primary-outcome population description is blank. These omissions limit assessment of whether the posted summaries align with the planned analysis and how missing or incomplete measurements affected the estimates.

The estimates should therefore be interpreted as reported summaries and unadjusted comparisons, with the crossover design and the unavailable analysis details in view. General statistical concepts can describe what means, differences, confidence intervals, and p-values convey, but cannot fill in unreported protocol decisions.

10. Confidence Intervals and Precision

Precision concerns how narrowly the data locate an effect estimate. The reported confidence intervals quantify uncertainty around the mean differences for each comparison. For refined wheat flour, the estimated difference is -17810.0 nmol/L*h, with a 95% confidence interval from -21910.0 to -13710.0. For liquid wholegrain barley flour, the estimate is -13970.0, with an interval from -18300.0 to -9645.0. For wholegrain barley flour, the estimate is -13720.0, with an interval from -18020.0 to -9425.0. Each interval is entirely below zero.

The intervals for liquid wholegrain wheat flour and wholegrain wheat flour are wider across both sides of zero: -7246.0 to 3146.0 and -7576.0 to 3140.0, respectively. Their point estimates are -2050.0 and -2218.0. These ranges allow for both a negative difference and a positive difference under the stated comparison, so the direction is not precisely established by these intervals. Their unadjusted p-values, 0.439 and 0.417, are consistent with the intervals' inclusion of zero.

In general, a confidence interval is not a guarantee that the true effect lies within its endpoints. It is a method-based range that reflects sampling uncertainty under its assumptions. Precision also differs from importance: a precisely estimated difference may not be clinically meaningful, and an imprecise estimate may include effects that would matter in either direction. The registry record does not report a clinically meaningful threshold for this biomarker.

The primary-outcome comparisons each report 13 participants per arm, but the registry record does not explain why this differs from the enrollment of 14. Nor does it report the within-participant covariance needed to reconstruct paired crossover intervals from the arm summaries. These limits matter when judging how completely the posted intervals capture uncertainty for the original design.

11. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The sample-size figures are planning illustrations, not the number enrolled or analyzed in the trial. For these continuous-outcome comparisons, the entries give participants per arm, not total events. The accompanying curve should be read as the same planning relationship in graphical form: smaller effects to detect require more participants. These values are not observed power.

The planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. Each illustration uses a stated fraction of the observed effect as the effect to detect. The figures are computed from the observed effect, not from the trial's original design. The trial's own sample-size justification and original planning assumptions are not reported in the registry record.

The 80% power column gives the estimated participants per arm for a design that would have an 80% chance of detecting the selected effect under the stated assumptions, if that effect were the true one. The 90% power column describes the corresponding planning target at 90% power. These are design calculations, not a retrospective statement about whether the completed trial had enough power or what it observed.

For example, planning for 100% of the observed effect in the refined wheat flour comparison gives 2 participants per arm for 80% power and 2 participants per arm for 90% power. Planning for 50% of that observed effect gives 6 and 8 participants per arm, respectively. The sample-size figures rise when the assumed effect is reduced because a smaller difference is harder to distinguish from random variation. These illustrations do not account for unreported crossover-specific features, multiplicity, missing data, or the original analysis plan.

12. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = -17809.000; pooled standard deviation σ = 5332.555.
2. n = 2 × (1.96 + 0.842)² × 5332.555² / -17809.000² = 1.4, rounded up to 2 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- -17809                      # observed difference in means
sigma <- 5332.55496924317                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(1287403)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 2 (80% power), 2 (90% power)
 75% of observed effect: n per arm = 3 (80% power), 4 (90% power)
 50% of observed effect: n per arm = 6 (80% power), 8 (90% power)
power.t.test: 2.8 
Simulated power at n = 2 per arm: 0.446 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

13. Multiplicity, Missing Data and Analysis Populations

The posted results include several comparisons against the esterase-treated wholegrain wheat flour reference, along with secondary outcomes covering plasma and urinary betaine and phenolic acids. The listed p-values are unadjusted. The registry record does not report whether the original analysis controlled the overall false-positive risk across multiple comparisons or outcomes, or whether any outcomes were prioritized beyond the posted primary designation. When many hypotheses are examined, unadjusted p-values do not account for the possibility of chance findings across that broader set.

The registry record does not report a multiplicity-adjustment method, a hierarchy for testing outcomes, or any interim analyses. The analysis plan and the rules used to choose which contrasts to report are also not reported in the registry record. These gaps make it difficult to judge how the displayed comparisons fit within the full set of analyses that may have been planned or performed. The posted p-values should therefore be read as unadjusted evidence for individual comparisons, not as family-wide error-controlled results.

Missing-data handling is also not reported in the registry record. Enrollment was 14, while the primary outcome summaries report 13 participants per arm. The reason for this difference, whether all participants contributed to every measurement, and how any unavailable blood samples or time points were handled are not described. The record does not provide an analysis-population definition or participant flow for the primary outcome. The primary-outcome population description is not reported in the registry record.

For a crossover study, missing observations in one period can affect within-participant comparisons differently from missing observations in all periods. The registry record does not state whether the analysis used complete cases, available observations, or another approach. It also does not report methods for handling period effects, treatment sequence, or carryover. These matters cannot be resolved using arm means and standard deviations alone. As a result, the posted summaries support interpretation of the reported estimates, but do not allow a full assessment of missingness or the analysis population.

14. 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 5% reporting threshold.

Most frequent non-serious adverse event terms

The adverse-event record lists 14 participants at risk for serious adverse events in each intervention group. It reports zero serious adverse events associated with each of the six preparations. These figures describe the registry's recorded counts; they do not establish that no unrecorded events occurred or quantify the likelihood of rare events.

For other adverse events, the record lists 14 participants at risk in each group. One associated event is reported for refined wheat flour, and zero are reported for each of the other preparations. No serious-event terms are listed. The type of the other event is not reported in the registry record. Death counts are not reported in the registry record.

In general, adverse-event counts are descriptive and depend on how events were defined, collected, and attributed. The registry record does not provide additional detail about event timing, severity for the non-serious event, or the attribution process. The recorded zero counts should be interpreted as counts in this small study, not as proof that a preparation cannot be associated with an adverse event. The crossover design and the registry's group-level reporting also mean these figures should be read as the record presents them rather than as a complete safety analysis.

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

The posted primary results indicate that the mean plasma alkylresorcinol AUC was much lower in the refined wheat flour, liquid wholegrain barley flour, and wholegrain barley flour arms than in the esterase-treated wholegrain wheat flour reference arm. Their estimated mean differences are negative, and their confidence intervals are entirely below zero. The comparisons for liquid wholegrain wheat flour and wholegrain wheat flour are less conclusive: their intervals include zero and their unadjusted p-values are 0.439 and 0.417. The data therefore show different degrees of statistical separation from the reference in the posted summaries.

These findings concern a biomarker response after cereal intake over 0 to 48 h. They do not show that a preparation improves health, prevents disease, or produces a lasting effect. The registry record does not report clinical outcomes, and it does not provide a threshold for a meaningful change in alkylresorcinol AUC. Statistical evidence that a mean differs from a reference is not the same as evidence that the difference matters to health.

The study's design and reporting place limits on interpretation. The registry classifies it as crossover, but treatment order, timing between conditions, and crossover-specific analysis methods are not reported in the registry record. The arm summaries do not show the within-participant relationship between responses. The reason the primary outcome summaries include 13 participants per arm when enrollment was 14 is also not reported. The posted p-values are unadjusted, and the record does not report how missing measurements or multiple comparisons were handled.

Accordingly, the results are best treated as estimates of short-term biomarker responses in this study, not as definitive rankings of clinical value among cereal preparations. The confidence intervals describe statistical uncertainty under their calculation assumptions; they do not incorporate every uncertainty created by unreported design and analysis details. Generalization beyond the participants and conditions in the registry record is not established by these summaries.

16. Why This Trial Matters Statistically

This study offers a useful example of how the statistical question depends on the endpoint and comparator. The primary endpoint compresses plasma measurements collected over time into an AUC over baseline. The comparison reference is esterase-treated wholegrain wheat flour, even though refined wheat flour is described as a negative control. Keeping those roles distinct helps prevent a contrast from being mistaken for a comparison against every possible control condition.

The results also illustrate why an estimate, its confidence interval, and its p-value should be read together. Three comparisons have intervals fully below zero and unadjusted p-values <0.001. The two wholegrain wheat comparisons have intervals spanning zero and larger unadjusted p-values. That contrast in statistical evidence is informative, but it does not turn a biomarker difference into a clinical conclusion. The endpoints, time window, and reference condition define what can be said.

The crossover classification raises a further statistical issue: participant-level pairing can matter. Within-person comparisons may have a different precision from comparisons based only on separate arm summaries, depending on how participant responses covary. The posted arm means and standard deviations do not disclose that relationship. The registry record's lack of detail about sequence, timing, and crossover analysis therefore limits how fully readers can assess the reported estimates.

Finally, planning illustrations based on observed effects are distinct from the study's original design decisions. They show how assumed effect size relates to prospective sample-size targets under explicit assumptions, but they do not explain why the trial enrolled its observed number of participants. Separating those concepts helps avoid interpreting a planning illustration as retrospective evidence about the reliability of the completed trial.

17. 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 primary outcome summaries report 13 participants in every arm, whereas enrollment is 14. The registry record does not explain the difference, identify who contributed data to each arm, or describe whether participants had missing time points. This prevents assessment of how complete the primary endpoint data were and whether missingness could have affected the estimates.

Although the study is classified as crossover, the registry record does not report the intervention sequence, period structure, interval between preparations, or washout procedures. It also does not describe how treatment, period, sequence, or carryover effects were handled. Those details are particularly relevant because the posted comparisons are recalculations from arm-level summaries rather than a reconstruction using participant-level paired observations. The covariance between responses within a participant is not reported.

The analysis plan, original sample-size justification, multiplicity strategy, and missing-data methods are not reported in the registry record. The posted p-values are unadjusted. Eligibility criteria beyond healthy status, the primary analysis population, and the method used to calculate AUC are also not described. The record lists secondary-outcome topics, but their numerical results are not included among the posted primary summaries.

These limitations do not negate the reported summaries, but they narrow what can be concluded from them. In particular, they prevent a complete appraisal of the original planned analysis, the effect of missing observations, and the precision of a crossover-specific treatment contrast. Generalization beyond this study's participants, preparations, and measurement interval is not established by the registry record.

18. Related Tutorials

19. Related Statistical Calculators

20. Sources

• ClinicalTrials.gov: Response of Alkylresorcinols to Different Cereals — NCT01287403.
• Registry record last updated 2018-08-31; status last verified 2018-08.
• Results first posted 2013-08-14.
• 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.

21. Record Summary

The registry record describes a completed randomized, quadruple-masked crossover study of six cereal preparations in healthy participants. Enrollment was 14. The primary endpoint was plasma alkylresorcinol-compound AUC over baseline, measured from 0 to 48 h after intake and expressed in nmol/L*h. Each arm's primary summary reports 13 participants.

Esterase-treated wholegrain wheat flour was the reference in the posted unadjusted comparisons. Refined wheat flour and the two barley preparations had negative estimated differences with confidence intervals entirely below zero. The two wholegrain wheat comparisons had confidence intervals that included zero. The record also lists plasma and urinary betaine and phenolic acids as secondary outcomes.

The registry record does not report the original statistical analysis plan, sample-size justification, crossover sequence and timing, multiplicity approach, or missing-data methods. The results describe short-term biomarker responses; clinical outcomes and a threshold for clinical importance are not reported in the registry record.