The association of pulmonary function with carotid atherosclerosis in older Chinese: Guangzhou Biobank Cohort Study-CVD Subcohort

Background: Evidence describing the association between pulmonary function and carotid atherosclerosis has been inconclusive and the role of smoking in this association is unclear. We therefore examined this association in the Guangzhou Biobank Cohort Study-CVD Subcohort. Methods: Common carotid artery (CCA) intima-media thickness (IMT) and carotid plaques were measured by B-mode ultrasonography and lung function by spirometry using a turbine flowmeter. Chronic obstructive pulmonary disease (COPD) was defined as the ratio of forced expiratory volume in 1 s (FEV₁) to forced vital capacity (FVC) of less than 0.70. Predicted FEV₁ and FVC were derived using equations for Chinese. Results: Of 1625 participants aged 50 + years, 382 (23.5%) had evidence of carotid plaque. The mean CCA-IMT was higher in those with COPD than those without (0.82 ± 0.29 mm versus 0.76 ± 0.31 mm, P = 0.02). We found no evidence that the association of pulmonary function with CCA-IMT varied by smoking status (P values interaction: 0.23-0.83). After adjustment for a wide range of potential confounders, the increased risks of thickened CCA-IMT (CCA-IMT ≥1.0 mm) in those with COPD became marginally nonsignificant (adjusted odds ratio (OR) 1.45, 95% confidence interval (CI) 0.91-2.29; P = 0.12). Compared to those in the highest tertile, participants in the lowest tertile of FEV₁ observed to predicted ratio had increased risk of thickened CCA-IMT (adjusted OR 2.18, 95% CI 1.42-3.34) and carotid plaque (adjusted OR 1.50, 95% CI 1.08-2.09), while participants in the lowest tertile of FVC observed to predicted ratio had increased risk of thickened CCA-IMT (adjusted OR 2.29, 95% CI 1.46-3.58), but the adjusted OR for carotid plaque was marginally nonsignificant (adjusted OR 1.29, 95% CI 0.93-1.80; P = 0.13). Conclusion: Independent of smoking status, poor pulmonary function was dose-dependently associated with carotid atherosclerosis in older Chinese. (281 words).