What question did this study set out to answer?

To evaluate the association and dose-response relationship between dietary total antioxidant capacity and the risk of chronic obstructive pulmonary disease.

August 15, 2026BMC Pulmonary MedicineOpen Access

Association between dietary total antioxidant capacity and chronic obstructive pulmonary disease: findings from the national health and nutrition examination survey

Q: What is the clinical evidence from this study?

Study design: Cross-Sectional. Population: Chronic Obstructive Pulmonary Disease (COPD) (n=29225). Intervention: Dietary total antioxidant capacity (TAC) vs. Lowest quartile of TAC (Q1). Primary outcome: Odds of COPD (self-reported physician diagnosis) (OR 0.78, 95% CI 0.62-0.99, p=0.040).

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Key result

Higher dietary total antioxidant capacity linked to ~22% lower odds of COPD.

OR 0.78
95% CI 0.62-0.99
P=0.040
n=29,225

Why the study?

This study aimed to investigate the association between dietary total antioxidant capacity and chronic obstructive pulmonary disease using NHANES data.

Does higher dietary total antioxidant capacity reduce the odds of chronic obstructive pulmonary disease in adults aged ≥ 40 years?

Key Points

To evaluate the association and dose-response relationship between dietary total antioxidant capacity and the risk of chronic obstructive pulmonary disease.
Analyzed cross-sectional data from 29,225 US participants aged ≥ 40 years across NHANES cycles (2001–2018), identifying 2,829 self-reported physician-diagnosed COPD cases.
Calculated dietary total antioxidant capacity (TAC) using 24-hour dietary recall data and categorized intake into quartiles (Q1–Q4).
Applied weighted multivariable logistic regression, restricted cubic splines (RCS), and inverse probability weighting to evaluate linear and nonlinear associations.
Compared to the lowest quartile (Q1), higher dietary TAC significantly reduced COPD odds in Q3 (OR = 0.71, 95% CI: 0.57–0.88, P = 0.003) and Q4 (OR = 0.78, 95% CI: 0.62–0.99, P = 0.040), with Q2 showing a non-significant reduction (OR = 0.83, 95% CI: 0.66–1.02, P = 0.084).
Restricted cubic spline analysis showed a significant nonlinear inverse dose–response relationship between dietary TAC and COPD risk (P for overall = 0.005; P for nonlinearity = 0.024).
Subgroup analyses revealed no significant effect modification across examined demographic or clinical strata (all P for interaction > 0.05).

Study Design

Type

Cross-Sectional (n=29,225)

Structured PICO

Does higher dietary total antioxidant capacity reduce the odds of chronic obstructive pulmonary disease in adults aged ≥ 40 years?

Population

29,225 U.S. adults aged 40 years and older from NHANES 2001-2018 were analyzed to assess the cross-sectional association between dietary total antioxidant capacity and COPD.

Exposure

Higher dietary total antioxidant capacity (TAC) calculated from 24-hour dietary recall data and categorized into upper quartiles (Q2, Q3, Q4).

Comparator

Lowest quartile of dietary total antioxidant capacity (Q1).

Outcome

Prevalence of chronic obstructive pulmonary disease (COPD) defined as a self-reported physician diagnosis.

Main Result

Odds Ratio: 0.78 (95% CI 0.62–0.99)

p-value: p=0.040

Higher dietary total antioxidant capacity is associated with a lower prevalence of COPD in a nonlinear dose-response manner, independent of smoking intensity.

Limitations

Cross-sectional design limits the ability to establish causal relationships
COPD status was based on self-reported physician diagnosis rather than spirometry
Dietary TAC was derived from a single 24-hour dietary recall, which may be subject to recall bias and database limitations
Potential residual confounding from unmeasured lifestyle or environmental exposures
Cross-sectional design precludes causal inference, warranting further longitudinal research.
TAC is a composite dietary metric derived from food composition databases rather than a direct biomarker, depending on the accuracy of dietary recall and databases.
Questionnaire-based definition of COPD (self-reported physician diagnosis) rather than spirometry across all cycles.

Discussion

No takes yet. Share an insight, caveat, or question.

Implication

Do not change COPD dietary counseling yet; leaves open a causal TAC effect pending longitudinal trials.

Cite This Study

Tan et al. (2026) conducted a cross-sectional in Chronic Obstructive Pulmonary Disease (COPD) (n=29,225). Dietary total antioxidant capacity (TAC) vs. Lowest quartile of TAC (Q1) was evaluated on Odds of COPD (self-reported physician diagnosis) (OR 0.78, 95% CI 0.62-0.99, p=0.040). Higher dietary total antioxidant capacity (highest vs lowest quartile) was associated with a 22% lower odds of COPD (OR 0.78, 95% CI 0.62-0.99) in U.S. adults.

synapsesocial.com/papers/6a801a0e75c2e31742c866cc https://doi.org/10.1186/s12890-026-04595-3

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Association between dietary total antioxidant capacity and chronic obstructive pulmonary disease: findings from the national health and nutrition examination survey

Key Points

Study Design

Structured PICO

Main Result

Limitations

Discussion

Implication

Cite This Study

Association between dietary total antioxidant capacity and chronic obstructive pulmonary disease: findings from the national health and nutrition examination survey

Key Points

Study Design

Structured PICO

Main Result

Limitations

Discussion

Implication

Cite This Study

Also Consider

Also Consider