Introduction: The 6-min walking distance (6MWD) test is a useful tool to obtain a measure of functional exercise capacity. However, reference equations have been mainly based on selected populations or small samples. The purpose of this study was to determine the reference equations to predict the 6MWD in a large Italian population sample of healthy adults of a wide age range.Methods: In the frame of the multi case–control population-based study Gene Environment Interaction in Respiratory Diseases (GEIRD), we studied 530 healthy subjects: 287 females ranging 21–76 and 243 males ranging 21–78 years of age. We measured 6MWD, demographic and anthropometric data and collected the reported physical activity. A multiple linear regression model for the 6MWD included age, age², height, weight and physical activity for both sex equations. The two-way interaction age-height and age-weight and the quadratic terms of weight and height were also tested for inclusion separately in each model.Results: The mean ± SD for 6MWD was 581.4 ± 66.5 m (range 383–800 m) for females and 608.7 ± 80.1 m (range 410–875 m) for males. The reference equations were 6MWD = 8.10*age + 1.61*height_cm−0.99*weight_kg + 22.58*active−0.10*age² + 222.55 for females (R squared = 0.238) and 6MWD = 26.80*age + 8.46*height_cm−0.45*weight_kg−2.54*active−0.06*age²−0.13*age*height_cm−890.18 for males (R squared = 0.159), where “active” is 1 when the subject is physically active, 0 otherwise.Conclusion: This study is the first to describe the 6MWD in a large population sample of young, middle aged and elderly healthy Caucasian subjects, and to determine reference equations. These findings will help to improve the evaluation of Italian and European patients with diseases influencing their functional capacity.

Little is known about the relationship between hemoglobin concentrations, functional status and health related quality of life (HRQL) in chronic obstructive pulmonary disease (COPD). Our aim was to investigate the prevalence of anemia and the association of hemoglobin with shortness of breath, exercise capacity, muscle strength and HRQL, in COPD patients. A total of 105 COPD patients (77 males, 71.6 ± 9.2 years) were studied. Patients were classified as anemic and non anemic using the WHO criteria. We used the Medical Research Council Dyspnoea scale (MRCs) to measure shortness of breath. Exercise capacity was assessed using the six minute walking distance (6MWD) and the peak of VO2 during the maximal cycle ergometer test (VO2max). We used the Quadriceps and Handgrip strength assessment to determine muscle strength. The Saint George Respiratory Questionnaire was used to investigate HRQL. The physiological/functional characteristics of the two groups were compared. Regression models adjusting for confounders examined the independent association of anemia and of hemoglobin levels with clinical and functional outcomes. Anemic patients (12.3%) showed a significantly higher MRCs, a lower 6MWD, VO2max, and a worse quality of life. On the contrary, there was no difference in muscle strength between the two groups. In the regression models, hemoglobin was independently associated with reduced exercise capacity and HRQL. Anemia in COPD was a risk factor for poorer exercise capacity and quality of life, and these outcomes were linearly associated with hemoglobin. Our results should stimulate further research into exploring whether increasing hemoglobin has a beneficial effect on the outcomes in COPD.

Few population-based studies have assessed the prevalence and the risk factors of non-allergic rhinitis (NAR) in comparison to allergic rhinitis (AR). Moreover, epidemiologic data on rhinitis in the elderly subjects and in southern Europe are scarce. This study aimed at estimating the prevalence and at comparing the risk factor distribution of AR and NAR in a general population sample aged 20–84 years in Italy. A questionnaire on respiratory symptoms and risk factors was administered to random samples of the Italian population aged 20–44 (n = 10,494) 45–64 (n = 2167) and 65–84 (n = 1030) in the frame of the Gene Environment Interactions in Respiratory Diseases (GEIRD) study. Current AR and NAR were defined according to the self-reported presence of nasal allergies or of nasal symptoms without a cold or the flu. NAR showed a significant descending pattern in females from 12.0 % (95 % CI 11.1, 13.1) in the 20–44 year age class, to 7.5 % (5.4, 10.3) in the 65–84 year age class (p = 0.0009), and a roughly stable pattern in males, from 10.2 % (9.3, 11.2) to 11.1 % (8.4, 13.9) (p = 0.5261). AR decreased from 26.6 % (25.7, 27.6) in 20–44 years age class to 15.6 % (13.3, 18.0) in the 65–84 years age class (p < 0.0001), without gender difference. Subjects living near industrial plants and ex- and current smokers had a higher risk of NAR. Current smokers had a lower risk and subjects living in a Mediterranean climate a higher risk of AR. AR and NAR are fairly distinct conditions, as they have a different age, gender and risk factor distribution.

Background: The identification of the factors associated with severe asthma may shed some light on its etiology and on the mechanisms of its development. We aimed to describe asthma severity using the Global Initiative for Asthma (GINA) classification and to investigate its determinants in a cross-sectional, population-based sample in Europe. Methods: In the European Community Respiratory Health Survey II (1999–2002), 1,241 adults with asthma were identified. Severity was assessed using the 2002 GINA classification (intermittent, mild persistent, moderate persistent, severe persistent) and it was related to potential determinants by a multinomial logistic model, using the intermittent group as the reference category for relative risk ratios. Results: About 30% of asthmatic subjects were affected by moderate-to-severe asthma. Sensitization to Cladosporium was associated with a more than 5-fold greater risk of having (mild, moderate or severe) persistent asthma than intermittent asthma. Persistent asthma was positively associated with sensitization to house dust mite, nonseasonal asthma, an older age at asthma onset, and chronic cough and phlegm. Sensitization to cat increased the risk of severe asthma only. Smoking was more strongly associated with asthma severity in men, while rhinitis was more strongly associated with asthma severity in women. Conclusions: One third of the asthmatic population have moderate-to-severe asthma. Sensitization to perennial indoor allergens, particularly Cladosporium, is strongly associated with asthma severity. The role of smoking and rhinitis in determining asthma severity may differ between the sexes, and it should be further investigated.

Introduction: The global burden of chronic airway diseases represents an important public health concern. The role of oxidative stress and inflammation in the pathogenesis of these diseases is well known. The aim of this study is to evaluate the behavior of both inflammatory and oxidative stress biomarkers in patients with chronic bronchitis, current asthma and past asthma in the frame of a population-based study. Methods: For this purpose, data collected from the Gene Environment Interactions in Respiratory Diseases (GEIRD) Study, an Italian multicentre, multicase-control study, was evaluated. Cases and controls were identified through a two-stage screening process of individuals aged 20-65 years from the general population. Out of 16,569 subjects selected from the general population in the first stage of the survey, 2259 participated in the clinical evaluation. Oxidative stress biomarkers such as 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG), 8-isoprostane and glutathione and inflammatory biomarkers such as Fractional Exhaled Nitric Oxide (FENO) and white blood cells were evaluated in 1878 subjects. Results: Current asthmatics presented higher levels of FENO (23.05 ppm), leucocytes (6770 n/µL), basophils (30.75 n/µL) and eosinophils (177.80 n/µL), while subjects with chronic bronchitis showed higher levels of GSH (0.29 mg/mL) and lymphocytes (2101.6 n/µL). The multivariable multinomial logistic regression confirmed high levels of leucocytes (RRR = 1.33), basophils (RRR = 1.48), eosinophils (RRR = 2.39), lymphocytes (RRR = 1.26) and FENO (RRR = 1.42) in subjects with current asthma. Subjects with past asthma had a statistically significant higher level of eosinophils (RRR = 1.78) with respect to controls. Subjects with chronic bronchitis were characterized by increased levels of eosinophils (RRR = 2.15), lymphocytes (RRR = 1.58), GSH (RRR = 2.23) and 8-isoprostane (RRR = 1.23). Conclusion: In our study, current asthmatics show a greater expression of the inflammatory profile compared to subjects who have had asthma in the past and chronic bronchitis. On the other hand, chronic bronchitis subjects showed a higher rate of expression of oxidative stress biomarkers compared to asthmatic subjects. In particular, inflammatory markers such as circulating inflammatory cells and FENO seem to be more specific for current asthma, while oxidative stress biomarkers such as glutathione and 8-isoprostane appear to be more specific and applicable to patients with chronic bronchitis.