A Study of the Combined Effects of Physical Activity and Air Pollution on Mortality in Elderly Urban Residents: The Danish Diet, XXXX , and Health Cohort.

@entity1 @entity7459 @entity6 @entity5 @entity2704 @entity6836 @entity1576 @entity65
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: We aimed 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: A total of 52,061 subjects (50-65 years of age) from the Danish Diet, @entity5 , and Health cohort, living in Aarhus and Copenhagen, reported data on physical activity in 1993-1997 and were followed until 2010. High exposure to air pollution was defined as the upper 25th percentile of modeled @entity7459 ( @entity6836 ) levels at residential addresses. We associated participation in sports, cycling, gardening, and walking with total and cause-specific mortality by Cox regression, and introduced @entity6836 as an interaction term. RESULTS: In total, 5,534 subjects died: 2,864 from @entity5 , 1,285 from @entity65 , 354 from @entity1576 , and 122 from @entity6 . Significant inverse associations of participation in sports, cycling, and gardening with total, cardiovascular, and @entity6 mortality were not modified by @entity6836 . Reductions in respiratory mortality associated with cycling and gardening were more pronounced among @entity1 with moderate/low @entity6836 [hazard ratio (HR) = 0.55; 95% CI: 0.42, 0.72 and 0.55; 95% CI: 0.41, 0.73, respectively] than with high @entity6836 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. Citation: Andersen ZJ, de Nazelle A, @entity2704 , Garcia-Aymerich J, Hertel O, Tj  nneland A, Overvad K, Raaschou-Nielsen O, Nieuwenhuijsen MJ. 2015. A study of the combined effects of physical activity and air pollution on mortality in elderly urban residents: the Danish Diet, @entity5 , and Health cohort. Environ Health Perspect 123:557-563;   http://dx.doi.org/10.1289/ehp.1408698.
