Abstract Rationale Vitamin A supports epithelial and mucous tissue integrity essential for healthy respiratory airways. While oxidative stress contributes to chronic pulmonary disease, evidence suggests that antioxidant nutrients like vitamin A and omega-3 fatty acids may offer protection. We examined the association between retinol intake and chronic bronchitis (CB) with its related symptoms. Methods Former smokers with COPD in low-income areas of Baltimore, Maryland, were enrolled in a prospective cohort study. Respiratory outcomes and dietary intake were assessed at 0, 3, 6-month. Cough and sputum production were assessed using the Ease of Cough and Sputum Clearance (ECSC) questionnaire and the Cough and Sputum Assessment Questionnaire (CASA-Q). CB was measured using the St. George’s Respiratory Questionnaire definition. Dietary intake was assessed by a food frequency questionnaire (FFQ). For each participant, average retinol intake (including supplements) –Retinol Activity Equivalent (RAE)–across visits was calculated. A generalized estimating equation (GEE) regression analysis was performed to assess the association between the repeated measures of respiratory outcomes with person-average retinol level, using Gaussian distribution and identity link for ECSC and CASA-Q; binomial distribution and logit link for CB. Models were adjusted by calorie, body mass index, age, gender, education, income, pack years, and baseline FEV1% predicted. Results 99 participants had their retinol intake measured during the study period. The participants were 56% female, 41% white, and 51% with some college or above, with the mean age of 66 (SD = 8) years. 44% of the participants had chronic bronchitis at baseline. The mean intake of retinol was 1372.9 mcg RAE/day (SD = 1132.0). Adjusting for covariates, higher retinol level was associated with improved cough and sputum severity. Based on the CASA-Q, one SD increase in retinol level was associated with improved cough symptoms (ß 3.415, P = 0.023), cough impact (ß 3.608, P = 0.030), and sputum symptoms (ß 4.177, P = 0.0156); the association with sputum impact did not reach statistical significance. The ECSC also showed association with retinol intake (Table 1). Additionally, one SD increase in retinol level was associated with 43% lower odds of chronic bronchitis (OR 0.57, P = 0.020). Results remained similar when additionally adjusting for omega-3 intake in sensitivity analysis. Conclusions Higher dietary retinol intake was linked to improved cough and sputum symptoms and lower odds of chronic bronchitis in former smokers with COPD, suggesting a protective role for retinol in respiratory health through antioxidant and anti-inflammatory effects. This abstract is funded by: NIH, Environmental
Quiroz et al. (2026) studied this question.