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Background: Breathlessness is a major cause of suffering and disability globally. The symptom relates to multiple factors including asthma and lung function, which are influenced by hereditary factors. No study has evaluated potential inheritance of breathlessness itself across generations.Methods: We analysed the association between breathlessness in parents and their offspring in the Respiratory Health in Northern Europe, Spain and Australia generation study. Data on parents and offspring aged ≥18 years across 10 study centres in seven countries included demographics, self-reported breathlessness, asthma, depression, smoking, physical activity level, measured Body Mass Index and spirometry. Data were analysed using multivariable logistic regression accounting for clustering within centres and between siblings.Results: A total of 1720 parents (mean age at assessment 36 years, 55% mothers) and 2476 offspring (mean 30 years, 55% daughters) were included. Breathlessness was reported by 809 (32.7%) parents and 363 (14.7%) offspring. Factors independently associated with breathlessness in parents and offspring included obesity, current smoking, asthma, depression, lower lung function and female sex. After adjusting for potential confounders, parents with breathlessness were more likely to have offspring with breathlessness, adjusted OR 1.8 (95% CI 1.1 to 2.9). The association was not modified by sex of the parent or offspring.Conclusion: Parents with breathlessness were more likely to have children who developed breathlessness, after adjusting for asthma, lung function, obesity, smoking, depression and female sex in both generations. The hereditary components of breathlessness need to be further explored. [ABSTRACT FROM AUTHOR]

Background: It has been debated, but not yet established, whether increased airway responsiveness can predict COPD. Recognising this link may help in identifying subjects at risk.Objective: We studied prospectively whether airway responsiveness is associated with the risk of developing COPD.Methods: We pooled data from two multicentre cohort studies that collected data from three time points using similar methods (European Community Respiratory Health Survey and Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults). We classified subjects (median age 37 years, 1st-3rd quartiles: 29-44) by their level of airway responsiveness using quintiles of methacholine dose-response slope at the first examination (1991-1994). Then, we excluded subjects with airflow obstruction at the second examination (1999-2003) and analysed incidence of COPD (postbronchodilator FEV1/FVC below the lower limit of normal) at the third examination (2010-2014) as a function of responsiveness, adjusting for sex, age, education, body mass index, history of asthma, smoking, occupational exposures and indicators of airway calibre.Results: We observed 108 new cases of COPD among 4205 subjects during a median time of 9 years. Compared with the least responsive group (incidence rate 0.6 per 1000/year), adjusted incidence rate ratios for COPD ranged from 1.79 (95% CI 0.52 to 6.13) to 8.91 (95% CI 3.67 to 21.66) for increasing airway responsiveness. Similar dose-response associations were observed between smokers and non-smokers, and stronger associations were found among subjects without a history of asthma or asthma-like symptoms.Conclusions: Our study suggests that increased airway responsiveness is an independent risk factor for COPD. Further research should clarify whether early treatment in patients with high responsiveness can slow down disease progression. [ABSTRACT FROM AUTHOR]

Background: International guidelines recommend that pulmonary reference populations consist of never-smokers without respiratory diseases or symptoms, but the diseases and symptoms are not clearly specified. The present study aimed to identify simple exclusion criteria for defining pulmonary reference populations. Methods: Based on a random sample from a general population (the parent population), 2358 subjects aged 26-82 years performed spirometric tests. From this sample, subjects were stepwise excluded according to self-reported obstructive lung diseases, symptoms and smoking history. Four increasingly more healthy respiratory reference populations were formed. Prediction equations for the median and lower limit of normal lung function were derived using quantile regression analysis. Results: Subjects without self-reported obstructive lung diseases or the cardinal respiratory symptoms of breathlessness, cough or wheeze (population B), never-smokers without cardinal symptoms (population C) and never-smokers without any respiratory symptoms (population D) constituted 50% (n = 1184), 23% (n = 539) and 14% (n = 331) of the parent population (population A), respectively. The largest discrepancy between prediction equations was found between the parent population and the population without cardinal respiratory symptoms (population B) (p<0.5). Minor changes in the reference equations were also seen when excluding ever-smokers (population C). There was no additional change with exclusion of other respiratory symptoms (population D). Age-related decline in lung function was steepest in the parent population. Conclusions: Obstructive lung diseases, smoking history, breathlessness, cough and wheeze are optimal exclusion criteria for a pulmonary reference population. Further validation of the exclusion criteria identified in this study is recommended with identical wording in other and larger multinational populations. [ABSTRACT FROM AUTHOR]