Bronchial hyper-responsiveness of women with asthma exposed to environmental tobacco smoke.

Effect of chronic environmental tobacco smoke (ETS) exposure on bronchial responsiveness (BR) was assessed by the measurement of BR in stable, nonsmoker asthmatic women and comparison of the PD20 in the exposed and non exposed groups was also studied. Nonspecific bronchoprovocation test was performed by histamine inhalational challenge. Of fifty patients included in the study, 23 (46%) had history of ETS exposure of 1.22 (+/- 0.61) hours per day for an average of 13.07 (+/- 6.1) years. The PD20 was significantly lower in the ETS exposed group (p < 0.05). When the subjects were compared, based on their cumulative exposure expressed by an exposure index (El = duration of exposure in years multiplied by average number of hours per day), there was a statistically significant difference in PD20 of those with El of less than those with El of more than 15. It is concluded that BR is greater, and reflects the higher morbidity in the ETS exposed patients of asthma.