Smoking habit, respiratory symptoms and lung function in young adults.
Smoking is the primary cause of deterioration in forced expiratory volume (FEV(1)) and the development of chronic obstructive lung disease. This study assessed the independent association of smoking with respiratory symptoms and lung function in young adults who took part in the European Community Respiratory Health Survey (ECRHS-I). Cross-sectional multi-centre survey of a general population of young adults aged 20(44 years in the ECRHS(I conducted in five Spanish centres. Several groups were created in an exclusive and descendent manner from the subjects who completed the questionnaire in accordance with how they had answered the questions: asthma-related symptoms; chronic bronchitis symptoms; minor respiratory symptoms; chronic cough; and no respiratory symptoms. Among a subset of the population, forced spirometry tests were performed. Linear and logistical regression models were used to assess the relationship of smoking in the presence of symptoms and its impact on lung function, adjusted by other important variables. The prevalence of respiratory symptoms was higher among smokers. After adjusting for geographical area, total IgE, age, sex, and FEV(1), smoking was associated with an increased risk of chronic bronchitis and other respiratory symptoms. These risks increased with increasing number of cigarettes smoked per day. A deterioration of FEV(1) and the FEV(1)/FVC ratio was also directly associated with the number of cigarettes smoked per day. Even among young adults, smoking confers a high risk of developing a number of respiratory symptoms and the deterioration of the ventilatory function.