Cos An international study, led in the University of Leuven (Belgium) and with the participation of investigators of Vall d'Hebron Institute of Research (VHIR), showed the relationship between the air pollution and mortality and the apparition of chronic graft dysfunction of lung-transplanted patients. The research, published in the European Respiratory Journal, counted with the biggest patient cohort ever analysed: 5.700 lung-transplanted patients in 13 hospitals of 10 European countries between 1987 and 2012. Cos Lung- transplanted patients are extremely vulnerable for their immunocompromised state. In these subjects, the transplantation was the last option of treatment, after suffering from respiratory pathologies such as pulmonary fibrosis, cystic fibrosis or pulmonary emphysema. Although the technique is applied since the 80s, the survival to the lung transplantation is one of the lowest compared to other solid organ, and it is near 5 years after the intervention, mainly because the patients develop chronic graft dysfunction, which is transplant rejection. Cos To determine whether pollution is associated to the mortality of transplanted patients and their graft dysfunction, the investigators decide to analyse the impact of suspended particles smaller than 10 µ,m, known as PM 10 , in the residence of transplanted patients. These particles float in the air and penetrate the bronchi and lungs of people when they breathe. To measure these particles, the researchers took the levels of PM 10 setin a European study performed in 2007. As a reference, WHO recommends that the median annual exposition to suspended particles does not exceed 20 µ,g/m3 and the daily median limit of 50 µ,g/m3, data that are under the current pollution levels in Barcelona. According the data of the Departament de Territori i Sostenibilitat, in 2015 the annual median of suspended particles in the Metropolitan Area of Barcelona was 27 µ,g/m3, and the limit of 50 µ,g/m3 fixed by WHO was exceeded during 20 days in different places in the city. Cos Patients' geolocation Cos VHIR researchers provide the study with the clinical information of approximately 450 lung-transplanted patients from 1997 and 2011 in the Vall d'Hebron University Hospital, and the data related to pollution in air and traffic near their residences. "Patient by patient, we counted the number of main roads and secondary roads near their residences in radius from 50 to 1.000 meters, as well as the length of the road, to determine if the exposition to traffic was a factor influencing the mortality", explains Dr. Antonio Román-Broto, head of the Pneumology Service, medical coordinator of the lung transplantation program and investigator at VHIR. Cos Once analysed the geocoded data of the 5.700 patients participating in the study, the investigators observed differences between the patients who had taken a kind of antibiotics, called macrolide antibiotics, with those patients who had not taken antibiotics. Cos In particular, they determined the relationship between the mortality rate and pollution in patients nor treated with macrolide antibiotics (3.556 patients). According to Dr. Román-Broto, the results of the study prove that "if we reduce the pollution levels to the limits recommended by WHO, we may prevent the 10% of mortality of lung-transplanted patients who do not take macrolide antibiotics". The study also reveals that two thirds of the patients lived in urban areas with high volume of traffic and levels upper than 20 µ,g/m3 recommended by WHO. Cos On the other hand, patients who took macrolide antibiotics -which are normally prescribed when there is a chronic graft dysfunction- presented a protection effect against pollution, a fact that requires more studies to be assessed. Cos VHIRVHIR was founded in 1994, it is part of the Vall d'Hebron University Hospital, of the Institut Català de la Salut, it is a CERCA center of the Departament d'Economia i Coneixement of the Generalitat and it is a research University Institute affiliated to the Universitat Autònoma de Barcelona.Vall d'Hebron Barcelona Hospital CampusThe Vall d'Hebron Campus comprises the Vall d'Hebron University Hospital, the Vall d'Hebron Institute of Research (VHIR), the Vall d'Hebron Institute of Oncology (VHIO) and the Multiple Sclerosis Centre of Catalonia (Cemcat). The new project represents a new way of working, where the research, teaching and clinical practice go together, in the same direction in order to pull together to become more useful, productive and effective.Bibliographic referenceD Ruttens, A Roman, S Gomez-Olles, C Berastegui et alt. An association of particulate air pollution and traffic exposure with mortality after lung transplantation in Europe. European Respiratory Journal. 2016. Doi: 10.1183/13993003.00484-2016