title: Quality of life in relation to the traffic pollution indicators NO2 and NOx: results from the Swedish GA(2)LEN survey.
abstract: BACKGROUND
  Asthma is a chronic disease that may affect daily activities and quality of life. Asthmatics have higher incidence of chronic rhinosinusitis (CRS) and asthma is associated with sinonasal inflammation and nasal symptoms, that all impair quality of life. Worsening of asthma has been found associated with levels of nitrogen dioxide as traffic indicator.
  
  
  OBJECTIVE
  The aim of the study was to evaluate the impact of traffic pollution indicated by nitrogen oxides (NO2 and NOx) on quality of life in asthmatic persons, individuals with CRS and controls.
  
  
  METHODS
  Within the Swedish Ga(2)len (Global Allergy and Asthma European Network), 605 asthmatics with and without CRS, 110 individuals with CRS only and 226 controls from four cities were surveyed. The mini Asthma Quality of life Questionnaire (mAQLQ) and the Euro Quality of Life (EQ-5D) health questionnaire were used. Air pollution concentrations at the home address were modelled using dispersion models.
  
  
  RESULTS
  Levels of NO2 (geometric mean 10.1 μg/m(3) (95% CI 9.80 to 10.5) and NOx (12.1 μg/m(3), 11.7 to 12.6) were similar among conditions (controls, asthmatics, individuals with CRS and asthmatics with CRS). The mAQLQ overall score was not found associated with levels of NO2 or NOx, with or without adjustments, and neither was scores within each of the four domains of mAQLQ: symptoms, activity limitations, emotional functions and effects of environmental stimuli. The mean EQ-5D index value, based on the five dimensions mobility, self-care, usual activities, pain/discomfort and anxiety depression, was also found unrelated to NO2 and NOx.
  
  
  CONCLUSIONS
  At moderate exposure levels traffic pollution appears not to affect quality of life.
authors.affiliation: Occupational and Environmental Medicine, Department of Public Health and Clinical Medicine , Umeå University , Umeå , Sweden.
authors.forename: Johan Nilsson
authors.initials: JN
authors.lastname: Sommar
authors.affiliation: Experimental Asthma and Allergy Research Unit , Institute of Environmental Medicine, Karolinska Institutet , Stockholm , Sweden.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Ek
authors.affiliation: The Centre for Allergy Research, Karolinska Institutet , Stockholm , Sweden ; The Institute of Environmental Medicine, Karolinska Institutet , Stockholm , Sweden.
authors.forename: Roelinde
authors.initials: R
authors.lastname: Middelveld
authors.affiliation: Department of Internal Medicine and Clinical Nutrition, Sahlgrenska Academy , Krefting Research Centre, University of Gothenburg , Göteborg , Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Bjerg
authors.affiliation: Experimental Asthma and Allergy Research Unit , Institute of Environmental Medicine, Karolinska Institutet , Stockholm , Sweden.
authors.forename: Sven-Erik
authors.initials: SE
authors.lastname: Dahlén
authors.affiliation: Department of Medical Sciences: Respiratory Medicine and Allergology , Uppsala University , Uppsala , Sweden.
authors.forename: Christer
authors.initials: C
authors.lastname: Janson
authors.affiliation: Occupational and Environmental Medicine, Department of Public Health and Clinical Medicine , Umeå University , Umeå , Sweden.
authors.forename: Bertil
authors.initials: B
authors.lastname: Forsberg
keywords: Asthma Epidemiology