LungVITamin D and OmegA-3 Trial (lungVITAL): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for LungVITamin D and OmegA-3 Trial (lungVITAL) (NCT01728571), a randomized na study. The primary outcome is COPD Exacerbations Expressed as Cumulative Rate/Year Over 5 Years.

2. Clinical Question

3. Trial Design

The LungVITamin D and OmegA-3 Trial, abbreviated lungVITAL in the registry title, is a randomized, triple-masked, factorial study sponsored by Brigham and Women's Hospital. The registry record lists an enrollment of 25871, a start date of 2010-07, primary completion on 2018-10-11, and status active, not recruiting. The phase is listed as NA. The record characterizes this respiratory study as ancillary to VITAL, a trial investigating vitamin D3 and omega-3 fatty acids in relation to cancer, heart disease, and stroke among people without a prior history of those illnesses.

The factorial arrangement assigns combinations of active vitamin D3, active fish oil, and their placebos. This structure can support separate comparisons for each supplement, but interpreting it fully requires knowing how the analysis handled the combined assignments and any interaction between treatments. Those analysis details are not reported in the registry record. The reported outcome summaries group participants under Active Vitamin D, Vitamin D Placebo, Active Omega-3 Fatty Acids, and Omega-3 Fatty Acids Placebo.

For the primary outcome, the registry describes a questionnaire-based measure of COPD respiratory exacerbations over 5 years. The outcome population is defined by COPD criteria based on questionnaire responses. Asthma exacerbations over 5 years are also posted as a secondary outcome. The record describes additional respiratory aims, including pneumonia, airflow obstruction or pulmonary-function decline, and asthma control, but does not provide posted results for those aims in the listed outcome summaries.

Randomization and triple masking are design features intended to reduce systematic differences in assignment and assessment. The exact masking roles, allocation procedure, and original design assumptions are not reported in the registry record. The posted outcome summaries therefore give descriptive rates and unadjusted comparisons, but do not establish the details of the full prespecified analysis plan.

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: Population with COPD. COPD was defined by questionnaire as doctor's diagnosis of COPD or emphysema, or chronic bronchitis by ATS-DLD criteria. Health care utilization (self-reported), a secondary outcome, was assessed as counts in the past year of emergency room visits or hospitalization for lung problems for those with COPD.

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 participants from the VITAL parent study (NCT01169259) were enrolled in this ancillary study, and were included in ascertainment of supplement effects on pneumonia.For all other outcomes, only participants meeting the criteria of specified in the outcomes described below in the subsequent sections of this document were enrolled in this study from the parent study (NCT01169259).

6. Primary Endpoint

The registry lists the primary outcome as COPD Exacerbations Expressed as Cumulative Rate/Year Over 5 Years, measured over 5 years.

The primary endpoint is the cumulative rate of COPD respiratory exacerbations per year over 5 years. For participants with COPD, an episode is defined as a flare-up of chest trouble during the past 12 months that was treated with additional antibiotic or steroid medication at home, or that resulted in hospitalization. This definition focuses on episodes serious enough to prompt treatment or hospital care, rather than all respiratory symptoms.

A rate outcome counts events relative to time, so a participant can contribute more than one exacerbation. It differs from a binary outcome that records only whether any event occurred. The registry gives the endpoint as a mean and standard deviation for each posted group, and the comparisons are expressed as rate ratios. A rate ratio compares the event rates between groups; a value of 1.0 corresponds to equal rates, while values above or below 1.0 indicate a higher or lower rate in the first group, respectively.

Repeated episodes are relevant to respiratory morbidity because counting them can reflect recurrence as well as the occurrence of any event. The questionnaire-based definition also makes the endpoint dependent on participant reporting and recall. How missing questionnaires or incomplete follow-up were handled is not reported in the registry record. The endpoint should therefore be read as the reported annualized rate under the recorded definition, not as a complete measure of every aspect of respiratory health.

7. Results Posted in the Registry

• Active Vitamin D: 0.27 versus 0.25 (exacerbations per year) on control; rate ratio 1.08 (95% CI 1.00–1.17, approximate, Poisson model); p ≈ 0.051.
• Active Omega-3 Fatty Acids: 0.27 versus 0.25 (exacerbations per year) on control; rate ratio 1.08 (95% CI 1.00–1.17, approximate, Poisson model); p ≈ 0.054.
• Omega-3 Fatty Acids Placebo: 0.25 versus 0.25 (exacerbations per year) on control; rate ratio 1.00 (95% CI 0.93–1.07, approximate, Poisson model); p ≈ 1.000.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Asthma Exacerbations Expressed as Cumulative Rate/Year Over 5 Years

• Endpoint type: Event rate: events per unit of follow-up, compared as a rate ratio.
• Test: Poisson rate ratio, based on the estimated number of events and follow-up time.
• Result:
  • Active Vitamin D: 0.27 versus 0.27 (asthma exacerbations per year) on control; rate ratio 1.00 (95% CI 0.92–1.09, approximate, Poisson model); p ≈ 1.000.
  • Active Omega-3 Fatty Acids: 0.29 versus 0.27 (asthma exacerbations per year) on control; rate ratio 1.07 (95% CI 0.99–1.17, approximate, Poisson model); p ≈ 0.086.
• Interpretation:
  • The 95% confidence interval includes no difference (a ratio of 1), so these data do not show a statistically significant difference between Active Vitamin D and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference (a ratio of 1), so these data do not show a statistically significant difference between Active Omega-3 Fatty Acids and the control. The interval gives the range of effects that remain compatible with the data.

The posted secondary outcome is asthma exacerbations expressed as a cumulative rate per year over 5 years. Its broad pattern resembles the primary outcome in that the group rates are close and the unadjusted comparisons do not give a sharp separation. The asthma results therefore do not provide a clear contrasting signal that would resolve the uncertainty in the COPD findings.

The secondary outcome is related to the primary result because both count recurrent respiratory exacerbations over the same stated timeframe, but they concern different conditions and outcome populations. A result in the asthma population does not directly confirm or refute a result in the COPD population. Nor does similarity in the estimates show that effects are identical across the conditions. The registry record does not report a formal comparison between those populations.

Secondary results generally carry less inferential weight when they are unadjusted and assessed alongside multiple outcomes or contrasts. Testing many questions increases the chance that at least one result will appear notable by chance. The registry record does not describe a multiplicity plan, hierarchy of outcomes, or a confirmatory role for the asthma outcome. It also lists no reported analyses for this secondary outcome, so the posted summary comparisons should not be treated as a fully documented sponsor analysis.

The record's broader respiratory aims include pneumonia, airflow obstruction or pulmonary-function decline, and asthma control, but corresponding results are not reported in the registry outcome summaries. Absence of a posted result is not evidence of no effect. Taken together, the secondary outcome provides context about the respiratory questions but does not strengthen a causal conclusion beyond what the primary summaries support.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Asthma Exacerbations Expressed as Cumulative Rate/Year Over 5 Years

9. Statistical Interpretation

10. Statistical Methods Explained

What is a rate ratio? A rate ratio compares event rates between two groups. In this outcome, the events are COPD exacerbations and the unit is exacerbations per year. A rate ratio of 1.0 represents equal rates. A value above 1.0 means the estimated rate is higher in the group named first in the comparison; a value below 1.0 means it is lower. It does not directly compare the proportion of participants who had any event, and it does not reveal how events were distributed among participants.

Why do recurrent events matter? Participants can experience repeated exacerbations, so an analysis of rates uses more information than a simple yes-or-no measure of whether an event occurred. It also brings assumptions about how event counts relate to exposure time and about variability in counts. The comparisons are marked as using a Poisson approach. In general, a Poisson model relates event counts to exposure and assumes a particular relationship between the mean and variance. If counts vary more than that model expects, over-dispersion can make standard errors too small and confidence intervals too narrow unless addressed. The registry record does not report a check for over-dispersion or a method for adjusting for it.

What is the role of the descriptive summaries? The group means and standard deviations describe the posted outcome summaries. The mean rate gives the average count per year, while the standard deviation describes variation around that mean. Neither quantity alone shows whether the distribution is skewed, whether a small number of participants had many events, or how many participants had no events. Those details are not reported in the registry record.

How should the p-values be read? A p-value describes how compatible the observed result is with a specified null model, under the assumptions of the analysis. A value near a conventional threshold does not measure the probability that the null hypothesis is true, nor does it give the size or clinical importance of a difference. The posted p-values are unadjusted. The registry record does not report a multiplicity adjustment, a prespecified threshold for the respiratory outcomes, or a formal analysis plan that would clarify how these results were intended to be interpreted together.

What does a confidence interval add? A confidence interval gives a range of effect values compatible with the data under the statistical model and its assumptions. For a rate ratio, an interval containing 1.0 includes the equal-rate value. An interval that also includes values on either side of 1.0 signals uncertainty about both the direction and size of the difference. It is not a range containing a fixed proportion of individual participants' rates; it describes uncertainty in the estimated group contrast.

What is not documented? The registry record does not report the complete analysis population, handling of missing outcome data, covariate adjustment, use of an intention-to-treat principle, or treatment adherence. It also does not report how the factorial design was incorporated into the primary comparison or whether an interaction was tested. These omissions prevent a full assessment of whether the simple posted comparisons match the intended sponsor analysis. No reported-analysis details are listed for the secondary outcome.

General statistical interpretation must therefore remain conditional on the methods actually used. Randomization can support causal comparisons when assignment, follow-up, analysis population, and outcome assessment are handled appropriately, but the registry summaries alone do not document each of those elements. The listed estimates are useful for describing the posted results, while the missing analysis details limit conclusions about robustness and generalizability.

11. Confidence Intervals and Precision

The primary rate-ratio estimates are 1.08 for Active Vitamin D and 1.08 for Active Omega-3 Fatty Acids. Their confidence intervals extend to 1.167 and 1.168, respectively, and each lower endpoint lies just below 1.0. Because both intervals include the equal-rate value, the posted data are compatible with no rate difference as well as with a higher rate in the active group. The intervals do not support a precise estimate of the direction or magnitude of a difference.

The corresponding unadjusted p-values are 0.051 and 0.054. These values are close to the conventional 0.05 reference point, but proximity to a threshold does not make an estimate precise or convert an uncertain result into a definitive one. Confidence intervals are more informative about the range of effect sizes compatible with the analysis than a threshold-based label alone.

The reported group means are rounded to two decimal places and the comparisons rely on event-count summaries. The registry record does not provide confidence intervals for each group mean, participant-level distributions, or sensitivity analyses. It also does not report whether the model accounted for any extra variability beyond the Poisson assumption. These gaps mean the interval widths should be understood in the context of the stated model, rather than as accounting for every possible source of uncertainty.

Precision is distinct from clinical importance. The registry record does not specify a minimum clinically important difference or an equivalence margin. Thus the intervals cannot be used to declare the groups clinically equivalent, and the estimates alone do not establish that a difference, if present, would matter to patients.

12. 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 planning figures are participant counts per arm, not total event counts. They are illustrations based on the observed effect, not the trial's original design assumptions. The planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. For scenarios using a fraction of the observed effect, the calculation targets the stated fraction. The original trial design assumptions are not reported in the registry record.

The 80% power column gives the number of participants per arm that the planning calculation estimates would be needed for an 80% chance of detecting the specified effect under those assumptions. The 90% power column gives the corresponding per-arm count for a 90% chance. These are planning probabilities under the calculation's model, not guarantees for a future study. The figures are not observed power.

The scenarios are labeled as planning for 100%, 75%, and 50% of the observed effect. For the primary comparisons, planning for 100% of the observed effect corresponds to 2,042 participants per arm for 80% power and 2,734 participants per arm for 90% power. Planning for 75% corresponds to 3,664 participants per arm for 80% power and 4,905 participants per arm for 90% power. Planning for 50% corresponds to 8,321 participants per arm for 80% power and 11,140 participants per arm for 90% power.

The pattern is expected: smaller effects are harder to distinguish from random variation, so they require more participants under otherwise similar assumptions. These calculations are illustrative rather than a retrospective measure of the chance that the completed trial detected an effect. They do not establish that the original study was designed around these respiratory outcomes.

13. 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, λ₀ and λ₁ are event rates per patient-year, and T is follow-up per participant in years. This assumes Poisson counts and equal follow-up.

Worked calculation for this trial

1. Control rate λ₀ = 0.2500; treatment rate λ₁ = 0.2700 events per patient-year; follow-up T = 5.00 years.
2. n = (1.96 + 0.842)² × (1/0.2500 + 1/0.2700) / (5.00 × [ln(1.080)]²) = 2,041.7, rounded up to 2,042 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
lambda0 <- 0.25                      # control rate, events per patient-year
lambda1 <- 0.27                      # treatment rate
tt      <- 5                       # follow-up per participant, years
n_per_arm <- function(power, frac = 1) {
  l1 <- lambda0 * (lambda1 / lambda0)^frac   # smaller effect = fraction of the observed log rate ratio
  ceiling(round((z_a + qnorm(power))^2 * (1 / lambda0 + 1 / l1) / (tt * log(l1 / lambda0)^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 = ",")))

# Simulation 1: Poisson counts. Simulation 2: over-dispersed counts (variance = 1.5 x mean), analysed with the matching variance.
set.seed(1728571)
n    <- n_per_arm(0.80)
reps <- 20000
m0 <- lambda0 * n * tt; m1 <- lambda1 * n * tt
x0 <- rpois(reps, m0); x1 <- rpois(reps, m1)
z  <- log(x1 / x0) / sqrt(1 / x0 + 1 / x1)
cat(sprintf("Simulated power, Poisson counts, n = %s per arm: %.3f\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE)))
phi <- 1.5
y0 <- rnbinom(reps, mu = m0, size = m0 / (phi - 1)); y1 <- rnbinom(reps, mu = m1, size = m1 / (phi - 1))
z2 <- log(y1 / y0) / sqrt(phi * (1 / y0 + 1 / y1))
cat(sprintf("Simulated power, over-dispersed counts (phi = 1.5), same n: %.3f\n", mean(abs(z2) > z_a, na.rm = TRUE)))

Output from running the code

100% of observed effect: n per arm = 2,042 (80% power), 2,734 (90% power)
 75% of observed effect: n per arm = 3,664 (80% power), 4,905 (90% power)
 50% of observed effect: n per arm = 8,321 (80% power), 11,140 (90% power)
Simulated power, Poisson counts, n = 2,042 per arm: 0.798
Simulated power, over-dispersed counts (phi = 1.5), same n: 0.631

The first simulation draws Poisson counts and should land close to the target power. The second allows extra variability (variance 1.5 times the mean, a purely illustrative value), which lowers the power at the same sample size, so rate trials usually need more participants than the Poisson formula suggests.

14. Multiplicity, Missing Data and Analysis Populations

The registry record describes a study with a factorial arrangement, a primary COPD exacerbation outcome, a secondary asthma exacerbation outcome, and broader respiratory aims. Multiple treatment contrasts and outcomes create a multiplicity issue: the more comparisons considered, the greater the chance that some may appear noteworthy through random variation. The record does not report whether a family of hypotheses was defined, whether any adjustment was used, or whether outcomes were ordered in a prespecified hierarchy. The posted p-values are unadjusted and should be interpreted with this uncertainty in mind.

The factorial design raises a separate question about whether the effects of vitamin D and omega-3 fatty acids were estimated independently, jointly, or with an interaction term. An interaction would address whether the effect of one supplement depends on assignment to the other. The analysis model and any interaction test are not reported in the registry record. The arm summaries alone do not establish how such effects were handled.

Missing-data procedures and analysis populations are also not reported. The record does not state how incomplete questionnaires, loss to follow-up, or unavailable outcome data were treated. It does not identify whether the posted populations were defined before analysis or whether all randomized participants were included under an intention-to-treat principle. The subgroup definition for COPD is described, but detailed inclusion flow and exclusions are not reported.

Other important details—including covariate adjustment, model diagnostics, sensitivity analyses, adherence handling, and the prespecified statistical plan—are not reported in the registry record. These omissions do not invalidate the descriptive summaries, but they constrain assessment of bias, robustness, and the relationship between the posted comparisons and the trial's intended confirmatory analyses.

15. Safety Results

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

Deaths

Other (non-serious) adverse events

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

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: invasive cancer of any type (6.4%), major cardiovascular event (3.2%), gastrointestinal bleeding (3.1%), hypercalcemia (1.2%).

The registry lists serious adverse event counts and numbers at risk for the vitamin D and omega-3 groupings, as well as for the four combinations of active treatments and placebos. For example, the serious-event counts are 1673 for Active Vitamin D and 1659 for Vitamin D Placebo; the corresponding listed numbers at risk are 12927 and 12944. For Active Omega-3 Fatty Acids and Omega-3 Fatty Acids Placebo, the counts are 1613 and 1619, with 12933 and 12938 at risk. These are descriptive counts, not adjusted comparisons.

The record also lists deaths by group and gives selected serious adverse event terms with percentages: Invasive cancer of any type, 6.4%; Major cardiovascular event, 3.2%; Gastrointestinal bleeding, 3.1%; and Hypercalcemia, 1.2%. The registry summary does not give comparative statistical analyses for these safety figures. The groupings overlap in the factorial design, so counts across them should not be added or treated as independent totals.

Without details about follow-up time, event definitions, ascertainment, and statistical comparisons, the counts cannot establish whether risks differed between assignments. They are safety summaries in the registry record, not a stand-alone estimate of treatment causality.

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

The posted primary results describe annualized COPD exacerbation rates that are close across the listed groups. The estimated rate ratios for active vitamin D and active omega-3 fatty acids are both 1.08 relative to the designated reference, and both confidence intervals include 1.0. The estimates point toward slightly higher recorded rates in the active groups, but the uncertainty does not permit a firm conclusion about the direction or size of a difference.

This does not show that the treatments work or do not work. A result that is not clearly separated from equal rates is not proof of no effect. Conversely, a point estimate above 1.0 is not proof that treatment increases exacerbations. The intervals and p-values describe uncertainty under the analysis model; they do not settle causal interpretation in the absence of detailed information about analysis populations, missing data, adherence, and the factorial analysis.

The endpoint is questionnaire-based and counts exacerbations meeting a treatment-or-hospitalization definition. It does not capture every symptom, all respiratory diagnoses, or all dimensions of pulmonary health. The record's broader aims include other outcomes, but their results are not reported in the posted outcome summaries. Conclusions should remain specific to the recorded endpoint and population.

The findings also should not be interpreted as proof of equivalence or as a clinical recommendation. No equivalence margin or threshold for an important difference is reported. The information supports a cautious description: observed group rates were similar in magnitude, and the statistical comparisons remain compatible with equal rates as well as some differences. Further interpretation depends on details not reported in the registry record.

17. Why This Trial Matters Statistically

This trial is statistically interesting because it combines a factorial treatment structure with a recurrent-event outcome. Factorial designs can evaluate more than one intervention efficiently, but clear interpretation depends on the analysis specifying how each factor and any interaction are handled. The registry record identifies the design as factorial but does not report those analysis details, illustrating why design labels alone are not enough to reconstruct an inferential plan.

Recurrent exacerbations also pose a different analytic problem from a single binary outcome. A rate can incorporate repeated events and exposure time, but it may depend on distributional assumptions about event counts and variability. The posted analysis is marked as Poisson-based, while diagnostics or adjustments for excess variability are not reported. This makes the model assumptions an important part of interpreting the confidence intervals.

The primary summaries emphasize the distinction between an estimated effect and its precision. Rate ratios above 1.0 do not by themselves establish a meaningful difference, and intervals that include 1.0 do not prove no effect. Unadjusted p-values near a conventional cutoff are especially difficult to interpret when multiple outcomes and comparisons are in play and the multiplicity plan is not reported.

Finally, the registry record allows readers to see both useful outcome summaries and the limits of what is documented. Descriptive results can inform understanding of a clinical question, but missing details about analysis populations, data handling, and prespecification matter when moving from summaries toward causal claims. This is a practical example of why transparent reporting of methods is essential alongside outcome estimates.

18. 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.
• Rate comparisons use a Poisson approximation unless the sponsor posted confidence limits; real event counts are often over-dispersed.

The primary outcome depends on questionnaire reports of COPD status and exacerbation episodes. Recall and classification may affect reported counts, and the registry record does not describe validation procedures or how uncertain responses were handled. The outcome is limited to flare-ups treated with additional antibiotic or steroid medication at home or resulting in hospitalization, so other respiratory symptoms are outside its stated definition.

The summary gives means, standard deviations, and event-count comparisons, but not participant-level event distributions. It is therefore not possible to determine from the registry record whether repeated events were broadly distributed or concentrated in a smaller subset. The posted comparisons use a Poisson approach, but model diagnostics and handling of possible over-dispersion are not reported.

Although the trial is described as randomized, triple masked, and factorial, details about allocation procedures, masking roles, adherence, interaction testing, covariate adjustment, missing outcomes, and the analysis population are not reported in the registry record. The COPD outcome population is defined by questionnaire criteria, but the record does not give a detailed participant flow for this endpoint.

The registry describes a broader set of respiratory aims, while only COPD and asthma exacerbation rate summaries are included in the posted outcome data. Results for pneumonia, airflow obstruction or pulmonary-function decline, and asthma control are not reported in these summaries. The outcome timeframe is 5 years, but details about individual follow-up duration and exposure time are not reported. These limitations restrict interpretation to the recorded summaries rather than the full respiratory research program.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: LungVITamin D and OmegA-3 Trial (lungVITAL) — NCT01728571.
• Registry record last updated 2026-08-07; status last verified 2026-07.
• Results first posted 2026-08-07.
• 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.

22. Record Summary

The registry record describes lungVITAL as a randomized, triple-masked, factorial ancillary study sponsored by Brigham and Women's Hospital, with enrollment of 25871. The study evaluates vitamin D3 and omega-3 fatty acids in relation to respiratory outcomes. The primary endpoint is the cumulative rate of COPD exacerbations per year over 5 years, defined using questionnaire-reported COPD and treated respiratory flare-ups.

The posted primary summaries show mean rates of 0.27 for Active Vitamin D and Active Omega-3 Fatty Acids, compared with 0.25 for Vitamin D Placebo. Both rate-ratio estimates are 1.08, with confidence intervals including 1.0 and unadjusted p-values of 0.051 and 0.054. Asthma exacerbation rates are also posted as a secondary outcome. The registry record does not report the full statistical plan, multiplicity handling, missing-data procedures, or detailed analysis populations, limiting stronger interpretation of these summaries.