Supranormal lung function and incident atrial fibrillation.

Abstract

Background: Whether supranormal lung function is associated with incident atrial fibrillation (AF), and whether obstructive sleep apnoea (OSA) modifies this association, remain to be determined.

Methods: We analysed 2,408 participants from the Sleep Heart Health Study who were free of AF at baseline and had no spirometric airflow obstruction. The primary analysis classified forced expiratory volume in 1 second (FEV₁) as below normal, normal, or supranormal using race-neutral Global Lung Function Initiative (GLI) Global (2022) reference equations. Categories defined by forced vital capacity (FVC) were examined in a secondary analysis. Associations with incident AF were evaluated using multivariable logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Firth penalised logistic regression and sensitivity analyses were used to assess the robustness of the findings. Interaction with OSA was explored.

Results: Among 2,408 participants, 282 developed AF. Compared with normal FEV₁, supranormal FEV₁ was associated with lower odds of incident AF in the primary adjusted model (OR, 0.420; 95% CI, 0.198-0.888). The corresponding Firth estimate was 0.443 (95% CI, 0.199-0.869). Supranormal FVC showed a similar association in standard logistic regression (OR, 0.351; 95% CI, 0.167-0.736) and Firth penalised logistic regression (OR, 0.371; 95% CI, 0.168-0.721). The direction of the associations was generally consistent across sensitivity analyses. There was no statistically significant evidence of effect modification by OSA.

Conclusions: Supranormal lung function was associated with lower odds of incident AF. These findings support supranormal spirometry as a potential marker of favourable systemic and cardiopulmonary physiology.