Association of Preserved Ratio Impaired Spirometry (PRISm) with Arterial Stiffness.

RATIONALE: Preserved ratio impaired spirometry (PRISm) is a recently recognized spirometric pattern defined by forced expiratory volume in 1 second (FEV1) / Forced vital capacity ratio ≥0.70 and FEV1 <80% of reference. For unclear reasons, PRISm is associated with increased cardiovascular (CV) morbidity and mortality. Arterial stiffness is a major mechanism of CV disease, which can be measured by carotid-femoral pulse wave velocity (cfPWV). OBJECTIVES: We explored the hypothesis that cfPWV would be increased in individuals with PRISm and airflow limitation (AL). METHODS: We measured forced spirometry, lung volumes by body plethysmography, and cfPWV in 9,466 subjects recruited from the general population in the Austrian cross-sectional LEAD study, and tested the association of arterial stiffness with PRISm and AL by multivariable linear regression analysis. Individuals aged 18 years and under as well as those with missing cfPWV or co-variates were excluded from further analysis. RESULTS: Individuals with PRISm (n = 431, 4.6%) were of similar age to those with normal spirometry (n = 8136, 85.9%) and significantly younger than those with AL (n = 899, 9.5%). Arterial hypertension, diabetes mellitus, coronary artery disease, heart failure and peripheral arterial occlusive disease were significantly more common in individuals with PRISm compared to normal lung function and similar to those with AL. There was a significant association between PRISm and arterial stiffness on bivariate linear regression analysis (crude model; ß = 0.038; 95% CI, 0.016 - 0.058), which persisted after robust adjustment for clinical confounders upon multivariable analysis (final model; ß = 0.017; 95% CI, 0.001 - 0.032). CfPWV was significantly higher in individuals with PRISm irrespective of the presence of established CV disease or pulmonary restriction. AL also showed a significant association with arterial stiffness on multivariable linear regression analysis (final model; 95% CI, ß = 0.025, 0.009 - 0.042). CONCLUSIONS: Arterial stiffness measured by cfPWV is increased in individuals with PRISm independent from CV disease and risk factors. The pathobiological mechanisms underlying this association deserve further research.

Updated reference values for static lung volumes from a healthy population in Austria.

BACKGROUND: Reference values for lung volumes are necessary to identify and diagnose restrictive lung diseases and hyperinflation, but the values have to be validated in the relevant population. Our aim was to investigate the Global Lung Function Initiative (GLI) reference equations in a representative healthy Austrian population and create population-derived reference equations if poor fit was observed. METHODS: We analysed spirometry and body plethysmography data from 5371 respiratory healthy subjects (6-80 years) from the Austrian LEAD Study. Fit with the GLI equations was examined using z-scores and distributions within the limits of normality. LEAD reference equations were then created using the LMS method and the generalized additive model of location shape and scale package according to GLI models. RESULTS: Good fit, defined as mean z-scores between + 0.5 and -0.5,was not observed for the GLI static lung volume equations, with mean z-scores > 0.5 for residual volume (RV), RV/TLC (total lung capacity) and TLC in both sexes, and for expiratory reserve volume (ERV) and inspiratory capacity in females. Distribution within the limits of normality were shifted to the upper limit except for ERV. Population-derived reference equations from the LEAD cohort showed superior fit for lung volumes and provided reproducible results. CONCLUSION: GLI lung volume reference equations demonstrated a poor fit for our cohort, especially in females. Therefore a new set of Austrian reference equations for static lung volumes was developed, that can be applied to both children and adults (6-80 years of age).

The effect of body compartments on lung function in childhood and adolescence.

BACKGROUND: There is an association between body composition and lung function, assessed by spirometry, but the effects of body compartments on static lung volumes and its changes during lung growth remain to be explored. We aimed to investigate the association of appendicular lean mass, reflecting skeletal muscle mass, and fat mass on forced and static lung function measures in childhood and adolescence. METHODS: In total, 1489 children and adolescents (6-18 years) of the observational, longitudinal (first and second visit within 4 years), general population-based LEAD study have been investigated. The association of appendicular lean mass and fat mass indices (ALMI and FMI; assessed by dual-energy X-ray absorptiometry) on lung function by spirometry (FEV1, FVC) and body plethysmography (TLC, RV, FRC) was investigated cross-sectionally. Longitudinal associations between lung function and body compartment changes between the two visits were analyzed. FINDINGS: The ALMI is positively associated with FEV1, FVC, and TLC. Contrary, FMI is inversely associated with lung function measures including FRC and RV. During the phase of lung growth, higher gain in muscle mass is associated with higher increases of FVC and TLC. INTERPRETATION: This study demonstrates the different effects of muscle and fat mass on forced expiratory and static lung volumes. Achieving and maintaining muscle mass in childhood and adolescence might become an important preventive strategy for lung health in adulthood.

Prevalence of chronic cough, its risk factors and population attributable risk in the Burden of Obstructive Lung Disease (BOLD) study: a multinational cross-sectional study.

Background: Chronic cough is a common respiratory symptom with an impact on daily activities and quality of life. Global prevalence data are scarce and derive mainly from European and Asian countries and studies with outcomes other than chronic cough. In this study, we aimed to estimate the prevalence of chronic cough across a large number of study sites as well as to identify its main risk factors using a standardised protocol and definition. Methods: We analysed cross-sectional data from 33,983 adults (≥40 years), recruited between Jan 2, 2003 and Dec 26, 2016, in 41 sites (34 countries) from the Burden of Obstructive Lung Disease (BOLD) study. We estimated the prevalence of chronic cough for each site accounting for sampling design. To identify risk factors, we conducted multivariable logistic regression analysis within each site and then pooled estimates using random-effects meta-analysis. We also calculated the population attributable risk (PAR) associated with each of the identifed risk factors. Findings: The prevalence of chronic cough varied from 3% in India (rural Pune) to 24% in the United States of America (Lexington,KY). Chronic cough was more common among females, both current and passive smokers, those working in a dusty job, those with a history of tuberculosis, those who were obese, those with a low level of education and those with hypertension or airflow limitation. The most influential risk factors were current smoking and working in a dusty job. Interpretation: Our findings suggested that the prevalence of chronic cough varies widely across sites in different world regions. Cigarette smoking and exposure to dust in the workplace are its major risk factors. Funding: Wellcome Trust.