Effect of tobacco smoking, respiratory symptoms and asthma on spirometry among adults attending a check-up clinic in Mexico City]

Objective. To evaluate the effect of tobacco smoking, respiratory symptoms, and asthma on lung function among Mexican adults who were evaluated during a medical exam in a private health clinic. Material and Methods. Reference prediction equations were generated for spirometry parameters [forced vital capacity (FVC),forced expired volume in one second (FEV1) and FEV1/FVC] based on multiple linear regression models. The effect of tobacco smoking, respiratory symptoms and asthma on these equations were explored. Results. Spirometry tests were performed on 919 subjects from 14 to 86 years of age. Asthma decreased FVC and FEV1 in men with a R-2 change < 1%. Respiratory symptoms decreased the FEV1/FVC ratio in both sexes. Tobacco smoking was associated with a significant reduction in FEV1 in women. Conclusions. Asthma lightly reduced lung function in males while tobacco smoking decreased FEV1, particularly in females.