Respiratory Symptoms in Young Adults and Future Lung Disease: The CARDIA Lung Study

RATIONALE: There are limited data on factors in young adulthood that predict future lung disease. OBJECTIVE: To determine the relationship between respiratory symptoms, loss of lung health, and incident respiratory disease in a population-based study of young adults. METHODS: Prospective data from 2749 participants in the Coronary Artery Risk Development in Young Adults (CARDIA) study who completed respiratory symptom questionnaires at baseline and 2 years later and repeated spirometry measurements over 30 years. MEASUREMENTS AND MAIN RESULTS: Cough or phlegm, episodes of bronchitis, wheeze, shortness of breath, and chest illnesses at both baseline and year 2 were the main predictor variables in models assessing decline in forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) from year 5 to year 30, incident obstructive and restrictive lung physiology, and visual emphysema on thoracic CT. After adjustment for covariates including body mass index (BMI), asthma, and smoking, report of any symptom was associated with -2.71 mL/year excess decline in FEV1 (p<0.001) and -2.18 in FVC (P<0.001) as well as greater odds of incident (pre-bronchodilator) obstructive (odds ratio (OR) 1.63, 95% CI 1.24, 2.14) and restrictive (OR 1.40, 95% CI 1.09, 1.80) physiology. Cough-related symptoms (OR 1.56, 95% CI 1.13, 2.16) were associated with greater odds of future emphysema. CONCLUSIONS: Persistent respiratory symptoms in young adults are associated with accelerated decline in lung function, incident obstructive and restrictive physiology, and greater odds of future radiographic emphysema.