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 R2 change <1%. Respiratory symptoms decreased the FEV1/FVC ratio in both sexes.Tobacco smoking was associated with a significant reduction in FEV in women. CONCLUSIONS: Asthma lightly reduced lung function in males while tobacco smoking decreased FEV, particularly in females.