Detection of early lung impairment with aerosol bolus dispersion.

The broadening of inhaled aerosol boluses (aerosol bolus dispersion) during respiration provides a noninvasive measure of convective gas mixing in the lungs. In this study, the sensitivity and specificity of this technique for the diagnosis of early lung impairment due to cigarette smoking was evaluated. Two hundred and sixteen randomly selected subjects (126 smokers and 90 nonsmokers) were investigated with aerosol dispersion in comparison to conventional lung function tests. The cumulative cigarette consumption of the subjects was quantified by 'pack-years' (PY). Smokers were classified into the following groups: 0< PY <10; 10< PY <20; 20< PY <30; and PY >30. Forced expiratory volume in one second (FEV1), maximal expiratory flow at 25, 50 and 75% vital capacity (MEF25, MEF50) and MEF75) decreased significantly with increasing cigarette consumption. In comparison to nonsmokers, FEV1 was significantly reduced in smokers of 10< PY <30, and MEF75 was significantly reduced in smokers of PY >20. Aerosol bolus dispersion increased with increasing PY. For all groups of smokers, even those with PY <10, bolus dispersion was significantly increased in comparison to lifelong nonsmokers, indicating alterations in convective gas mixing in the lungs. Calculation of receiver operating characteristics for the lung function parameters under consideration showed that bolus dispersion has a higher sensitivity and specificity than conventional lung function parameters. Hence, the aerosol bolus dispersion test could be a promising epidemiological tool to study early abnormalities in intrapulmonary gas mixing due to environmental factors

Prediction of new-onset asthma and nasal allergy by skin prick test and RAST in a cohort of adults.

Limited information exists regarding the incidence and predictors of asthma and nasal allergy in adulthood. We determined the incidence rate of asthma and nasal allergy in adults and assessed the predictive value of skin prick tests (SPTs) and radioallergosorbent tests (RASTs) for these two outcomes. Two German centres involved in the European Community Respiratory Health Survey conducted a follow-up assessment in 2012 of the baseline participants (1185 adults aged 21-47 years assessed in 1990). The predictive value of SPTs and RASTs on new-onset asthma and nasal allergy was assessed by Cox regression and by calculating the positive or negative predictive value. During the 20 years between baseline and follow-up, 3.1 and 4.4 per 1000 person-years of new-onset asthma and nasal allergy cases were recorded, respectively. The hazard ratios for SPTs of any specific and of all aeroallergens combined were slightly higher than those of RASTs for asthma and nasal allergy. The negative predictive values of both the SPT and EAST were very high and similar (0.94-0.96), whereas the postive predictive values were low (0.09-0.20). Positive SPT results showed a better association with new onset asthma and nasal allergy than positive EAST either to any specific aeroallergens or to all combined