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Background: Chronic obstructive pulmonary disease (COPD) affecting 334 million people in the world remains a major cause of morbidity and mortality. Proper diagnosis of COPD is still a challenge and largely solely based on spirometric criteria. We aimed to investigate the potential of nitrosative/oxidative stress and related metabolic biomarkers in exhaled breath condensate (EBC) to discriminate COPD patients. Methods: Three hundred three participants were randomly selected from a 15,000-transit worker cohort within the Respiratory disease Occupational Biomonitoring Collaborative Project (ROBoCoP). COPD was defined using the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria as post-bronchodilator ratio of Forced Expiratory Volume in 1st second to Forced Vital Capacity < 0.7 in spirometry validated by an experienced pulmonologist. Discriminative power of biomarker profiles in EBC was analyzed using linear discriminant analyses. Results: Amongst 300 participants with validated spirometry, 50.3% were female, 52.3 years old in average, 36.0% were current smokers, 12.7% ex-smokers with mean tobacco exposure of 15.4 pack-years. Twenty-one participants (7.0%) were diagnosed as COPD, including 19 new diagnoses, 12 of which with a mild COPD stage (GOLD 1). Amongst 8 biomarkers measured in EBC, combination of 2 biomarkers, Lactate and Malondialdehyde (MDA) significantly discriminated COPD subjects from non-COPD, with a 71%-accuracy, area under the receiver curve of 0.78 (p-value < 0.001), and a negative predictive value of 96%. Conclusions: These findings support the potential of biomarkers in EBC, in particular lactate and MDA, to discriminate COPD patients even at a mild or moderate stage. These EBC biomarkers present a non-invasive and drugless technique, which can improve COPD diagnosis in the future. [ABSTRACT FROM AUTHOR]

A study published in the journal Clinical & Experimental Allergy investigated the connection between long-term exposure to particulate matter (PM10) in subway environments and the prevalence of asthma in subway workers. The study discovered that there was a link between the concentration of nitrite in exhaled breath condensate (EBC) and atopic sensitization, poly-atopic sensitization, and current asthma. Nitrate levels, on the other hand, were negatively associated with current eczema. The study used a retrospective exposure assessment method and had a high response rate, but it had limitations such as a small sample size and reliance on self-reported data. The study emphasizes the risk of allergic asthma in subway settings and the potential use of noninvasive biomarkers in occupational allergology research. [Extracted from the article]