Citation
Andersen, Zorana Jovanovic; de Nazelle, Audrey; Mendez, Michelle A.; Garcia-Aymerich, Judith; Hertel, Ole; Tjonneland, Anne; Overvad, Kim; Raaschou-Nielsen, Ole; & Nieuwenhuijsen, Mark J. (2015). A Study of the Combined Effects of Physical Activity and Air Pollution on Mortality in Elderly Urban Residents: The Danish Diet, Cancer, and Health Cohort. Environmental Health Perspectives, 123(6), 557-563. PMCID: PMC4455593Abstract
BACKGROUND: Physical activity reduces, whereas exposure to air pollution increases the risk of premature mortality. Physical activity amplifies respiratory uptake and deposition of air pollutants in the lung, which may augment acute harmful effects of air pollution during exercise.OBJECTIVES: To examine whether benefits of physical activity on mortality are moderated by long-term exposure to high air pollution levels in an urban setting.
METHODS: 52,061 subjects (50-65 years) from the Danish Diet, Cancer, and Health cohort, living in Aarhus and Copenhagen reported data on physical activity in 1993-97 and were followed until 2010. High exposure to air pollution was defined as the upper 25th percentile of modelled nitrogen dioxide (NO2) levels at residential addresses. We associated participation in sports, cycling, gardening, and walking with total and cause-specific mortality by Cox regression, and introduced NO2 as an interaction term.
RESULTS: 5,534 subjects died in total: 2,864 from cancer, 1,285 from cardiovascular disease, 354 from respiratory disease, and 122 from diabetes. Significant inverse associations of participation in sports, cycling, and gardening with total, cardiovascular, and diabetes mortality were not modified by NO2. Reductions in respiratory mortality associated with cycling and gardening were more pronounced among participants with moderate/low NO2 (hazard ratio (HR) = 0.55; 95% CI: 0.42, 0.72 and 0.55; 95% CI: 0.41, 0.73, respectively) than with high NO2 exposure (HR = 0.77; 95% CI: 0.54, 1.11 and HR = 0.81; 95% CI: 0.55, 1.18, p-interaction = 0.09 and 0.02, respectively).
CONCLUSIONS: In general, exposure to high levels of traffic-related air pollution did not modify associations indicating beneficial effects of physical activity on mortality. These novel findings require replication in other study populations.
URL
http://dx.doi.org/10.1289/ehp.1408698Reference Type
Journal ArticleYear Published
2015Journal Title
Environmental Health PerspectivesAuthor(s)
Andersen, Zorana Jovanovicde Nazelle, Audrey
Mendez, Michelle A.
Garcia-Aymerich, Judith
Hertel, Ole
Tjonneland, Anne
Overvad, Kim
Raaschou-Nielsen, Ole
Nieuwenhuijsen, Mark J.