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Background Pollen exposure has acute adverse effects on sensitized individuals. Information on the prevalence of respiratory diseases in areas with different pollen concentrations is scanty. Aim We performed an ecologic analysis to assess whether the prevalence of allergic rhinitis and asthma in young adults varied across areas with different pollen concentrations in Italy. Methods A questionnaire on respiratory diseases was delivered to random samples of 20–44 year-old subjects from six centers in 2005–2010. Data on the daily air concentrations of 7 major allergologic pollens ( Poaceae , Urticaceae , Oleaceae , Cupressaceae , Coryloideae , Betula and Ambrosia ) were collected for 2007–2008. Center-specific pollen exposure indicators were calculated, including the average number of days per year with pollens above the low or high concentration thresholds defined by the Italian Association of Aerobiology. Associations between pollen exposure and disease prevalence, adjusted for potential confounders, were estimated using logistic regression models with center as a random-intercept. Results Overall, 8834 subjects (56.8%) filled in the questionnaire. Allergic rhinitis was significantly less frequent in the centers with longer periods with high concentrations of at least one (OR per 10 days = 0.989, 95%CI: 0.979–0.999) or at least two pollens (OR = 0.974, 95%CI: 0.951–0.998); associations with the number of days with at least one (OR = 0.988, 95%CI: 0.972–1.004) or at least two (OR = 0.985, 95%CI: 0.970–1.001) pollens above the low thresholds were borderline significant. Asthma prevalence was not associated with pollen concentrations. Conclusions Our study does not support that the prevalence of allergic rhinitis and asthma is greater in centers with higher pollen concentrations. It is not clear whether the observed ecologic associations hold at the individual level. [ABSTRACT FROM AUTHOR]

Background: The joint distribution of asthma and chronic obstructive pulmonary disease (COPD) has not been well described. This study aims at determining the prevalence of self-reported physician diagnoses of asthma, COPD and of the asthma-COPD overlap syndrome and to assess whether these conditions share a common set of risk factors. Methods: A screening questionnaire on respiratory symptoms, diagnoses and risk factors was administered by mail or phone to random samples of the general Italian population aged 20–44 (n = 5163) 45–64 (n = 2167) and 65–84 (n = 1030) in the frame of the multicentre Gene Environment Interactions in Respiratory Diseases (GEIRD) study. Results: A physician diagnosis of asthma or COPD (emphysema/chronic bronchitis/COPD) was reported by 13% and 21% of subjects aged <65 and 65–84 years respectively. Aging was associated with a marked decrease in the prevalence of diagnosed asthma (from 8.2% to 1.6%) and with a marked increase in the prevalence of diagnosed COPD (from 3.3% to 13.3%). The prevalence of the overlap of asthma and COPD was 1.6% (1.3%–2.0%), 2.1% (1.5%–2.8%) and 4.5% (3.2%–5.9%) in the 20–44, 45–64 and 65–84 age groups. Subjects with both asthma and COPD diagnoses were more likely to have respiratory symptoms, physical impairment, and to report hospital admissions compared to asthma or COPD alone (p<0.01). Age, sex, education and smoking showed different and sometimes opposite associations with the three conditions. Conclusion: Asthma and COPD are common in the general population, and they coexist in a substantial proportion of subjects. The asthma-COPD overlap syndrome represents an important clinical phenotype that deserves more medical attention and further research. [ABSTRACT FROM AUTHOR]