Effect of Passive Smoking on the Growth of Pulmonary Function and Respiratory Symptoms in Schoolchildren.

BACKGROUND

Environmental tobacco smoke affects the current and future health of children.

OBJECTIVE

To determine whether schoolchildren aged 8-17 years old residing at an altitude of 2,240 m and exposed to tobacco smoke at home presented a reduction in the growth of pulmonary function and a greater problem of respiratory symptoms and infections compared with non-exposed children.

MATERIALS AND METHODS

We followed, with questionnaires and spirometry, 1,632 boys and 1,555 girls from Mexico City and its metropolitan area (the Metropolitan Study to Evaluate the Chronic Effects of Pollution in School-age Children [EMPECE]) every six months for six years. The impact of passive smoking was estimated by mixed-effects models and Generalized Linear and Latent Mixed Models (GLLAMM), stratifying by gender and adjusting for age, height, weight, and ozone levels.

RESULTS

Passive smoking (reported by one-half of participants) was associated with reduced spirometric lung function (log transformed or as Z-scores) and a higher frequency of self-reported respiratory symptoms and respiratory infections. Levels of forced expiratory volume in 1 second and forced vital capacity in individuals exposed to passive smoking were 6.8 and 14.1 ml, respectively, below those of non-exposed children, and these values decreased with increasing number of smokers at home and higher ozone levels.

CONCLUSIONS

Passive smoking in children is a significant risk factor for respiratory disease and reduced lung function growth, which are additive with levels of air pollution, asthma, and the presence of respiratory symptoms.