Mortality Associations with Long-Term Exposure to Outdoor Air Pollution in a National English Cohort

• Published in: American journal of respiratory and critical care medicine 2013-06, Vol.187 (11), p.1226-1233
• Main Authors: CAREY, Lain M, ATKINSON, Richard W, KENT, Andrew J, STAA, Tjeerd Van, COOK, Derek G, ANDERSON, H. Ross
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Air Pollutants - adverse effects; Air pollution; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Body mass index; Cardiovascular disease; Cause of Death - trends; Censuses; Chronic obstructive pulmonary disease; Clinical medicine; Cohort analysis; Environment. Living conditions; Environmental Illness - mortality; Follow-Up Studies; Humans; Intensive care medicine; Lung cancer; Medical sciences; Middle Aged; Mortality; Nitrogen dioxide; Outdoor air quality; Ozone; Patients; Pneumology; Pollutants; Practice research; Public health. Hygiene; Public health. Hygiene-occupational medicine; Retrospective Studies; Risk Factors; Smoking; Socioeconomic factors; Survival Rate - trends; Time Factors; United Kingdom - epidemiology
• ISSN: 1073-449X; 1535-4970; 1535-4970
• DOI: 10.1164/rccm.201210-1758OC

Cohort evidence linking long-term exposure to outdoor particulate air pollution and mortality has come largely from the United States. There is relatively little evidence from nationally representative cohorts in other countries. To investigate the relationship between long-term exposure to a range of pollutants and causes of death in a national English cohort. A total of 835,607 patients aged 40-89 years registered with 205 general practices were followed from 2003-2007. Annual average concentrations in 2002 for particulate matter with a median aerodynamic diameter less than 10 (PM(10)) and less than 2.5 μm (PM(2.5)), nitrogen dioxide (NO(2)), ozone, and sulfur dioxide (SO(2)) at 1 km(2) resolution, estimated from emission-based models, were linked to residential postcode. Deaths (n = 83,103) were ascertained from linkage to death certificates, and hazard ratios (HRs) for all- and cause-specific mortality for pollutants were estimated for interquartile pollutant changes from Cox models adjusting for age, sex, smoking, body mass index, and area-level socioeconomic status markers. Residential concentrations of all pollutants except ozone were positively associated with all-cause mortality (HR, 1.02, 1.03, and 1.04 for PM(2.5), NO(2), and SO(2), respectively). Associations for PM(2.5), NO(2), and SO(2) were larger for respiratory deaths (HR, 1.09 each) and lung cancer (HR, 1.02, 1.06, and 1.05) but nearer unity for cardiovascular deaths (1.00, 1.00, and 1.04). These results strengthen the evidence linking long-term ambient air pollution exposure to increased all-cause mortality. However, the stronger associations with respiratory mortality are not consistent with most US studies in which associations with cardiovascular causes of death tend to predominate.