We have confirmed the important role of several risk factors for BHR
Pisa, the slope values began to go up from 25 to 34 years, while in Po Delta from 45 to 54 years. Moreover, in Pisa, the highest slope values were reached at 65 to 74 years while in Po Delta at 8 to 14 years. “Current smokers” showed mean slope values significantly higher than “ex-smokers” and “never-smokers” in Po Delta; the same difference, although not significant, was observed in Pisa. In both samples, mean ln slope values showed a significantly increasing trend from the “others” through the “chronic bronchitis-like subjects” up to the “asthmalike subjects”; further, mean ln slope values were significantly higher in atopic subjects (high values of IgE or positive skin-prick test reaction).
By logistic regression analysis, the risk factors significantly associated with an elevated ln slope value were as follows: female gender, younger age (8-14 years and 15-24 years), current smokers, asthma-like subjects, positive Viagra online in Australia skin-prick test reaction, and elevated log IgE value (Table 5). Moreover, airway caliber had a significant protective relationship with BHR. After controlling for the independent effects of all these variables, people living in the urban area had an odds ratio (OR) of 1.41 of getting BHR with respect to people living in the rural area (Table 5). No significant association was found between BHR and either work or passive smoking exposure.
Discussion
We have confirmed the important role of several risk factors for BHR. The significantly higher risk of an elevated ln slope of the dose-response curve in female Viagra online Canada subjects is in agreement with previous studies on adults and on children. Possible mechanisms, as reported by Paoletti are a higher cholinergic irritability in female subjects and hormonal differences related to sex (such as pregnancy and menstrual cycle).
The distribution of BR by age showed a “U” pattern, with the highest values corresponding to the youngest and oldest ages. Sparrow and Weiss had already indicated larger BHR values at the age extremes. These results were confirmed partially by Renwick and Con-nolly, who described a weak positive association between BHR and age in a population sample aged 45 to 86 years, and by Schwartz who found the highest BHR values in the younger subjects within a sample aged 18 to 60 years.