Background:Outdoor fine particulate matter (≤ 2.5 μm; PM2.5) has been identified as a global health threat, but the number of large U.S. prospective cohort studies with individual participant data remains limited, especially at lower recent exposures.Objectives:We aimed to test the relationship between long-term exposure PM2.5 and death risk from all nonaccidental causes, cardiovascular (CVD), and respiratory diseases in 517,041 men and women enrolled in the National Institutes of Health-AARP cohort.Methods:Individual participant data were linked with residence PM2.5 exposure estimates across the continental United States for a 2000–2009 follow-up period when matching census tract–level PM2.5 exposure data were available. Participants enrolled ranged from 50 to 71 years of age, residing in six U.S. states and two cities. Cox proportional hazard models yielded hazard ratio (HR) estimates per 10 μg/m3 of PM2.5 exposure.Results:PM2.5 exposure was significantly associated with total mortality (HR = 1.03; 95% CI: 1.00, 1.05) and CVD mortality (HR = 1.10; 95% CI: 1.05, 1.15), but the association with respiratory mortality was not statistically significant (HR = 1.05; 95% CI: 0.98, 1.13). A significant association was found with respiratory mortality only among never smokers (HR = 1.27; 95% CI: 1.03, 1.56). Associations with 10-μg/m3 PM2.5 exposures in yearly participant residential annual mean, or in metropolitan area-wide mean, were consistent with baseline exposure model results. Associations with PM2.5 were similar when adjusted for ozone exposures. Analyses of California residents alone also yielded statistically significant PM2.5 mortality HRs for total and CVD mortality.Conclusions:Long-term exposure to PM2.5 air pollution was associated with an increased risk of total and CVD mortality, providing an independent test of the PM2.5–mortality relationship in a new large U.S. prospective cohort experiencing lower post-2000 PM2.5 exposure levels.Citation:Thurston GD, Ahn J, Cromar KR, Shao Y, Reynolds HR, Jerrett M, Lim CC, Shanley R, Park Y, Hayes RB. 2016. Ambient particulate matter air pollution exposure and mortality in the NIH-AARP Diet and Health cohort. Environ Health Perspect 124:484–490; http://dx.doi.org/10.1289/ehp.1509676
BACKGROUND
Long-term exposure to ambient particulate matter (PM) air pollution is associated with increased cardiovascular disease (CVD); however, the impact of PM on clinical risk factors for CVD in healthy subjects is unclear. We examined the relationship of PM with levels of circulating lipids and blood pressure in the Third National Health and Nutrition Examination Survey (NHANES III), a large nationally-representative US survey.
METHODS
This study was based on 11,623 adult participants of NHANES III (1988–1994; median age 41.0). Serum lipids and blood pressure were measured during the NHANES III examination. Average exposure for 1988–1994 to particulate matter <10µm in aerodynamic diameter (PM10) at the residences of participants was estimated based on measurements from U.S. Environmental Protection Agency monitors. Multivariate linear regression was used to estimate the associations of PM10 with lipids and blood pressure.
RESULTS
An interquartile range width (IQRw) increase in PM10 exposure (11.1 µg/m3) in the study population was associated with 2.42 percent greater serum triglycerides (95% confidence interval [CI]: 1.09–3.76); multivariate adjusted means of triglycerides according to increasing quartiles of PM10 were 137.6, 142.5, 142.6, and 148.9 mg/dL, respectively. An IQRw increase in PM10 was associated with 1.43 percent greater total cholesterol (95% CI: 1.21–1.66). These relationships with triglycerides and total cholesterol did not differ by age or region. Associations of PM10 with blood pressure were modest.
CONCLUSIONS
Findings from this large diverse study indicate that greater long-term PM10 exposure is associated with elevated serum triglycerides and total cholesterol, potentially mediating air pollution-related effects on CVD.
Our objective was to determine whether conidia from non-woven fiber bands impregnated with Metarhizium anisopliae F 52 could be spread to other parts of the environment, and whether Anoplophora glabripennis could become infected with conidia dispersed from fungal bands. In the field, bands containing M. anisopliae were hung at 3 m height on 15 trees. Bark samples were taken 10, 20, and 30 cm above the bands and 10, 30, and 60 cm below the bands 2, 5, and 9 days after band placement to quantify conidial densities. There were more conidia in samples taken below bands compared with samples taken above bands. A significant positive correlation was found between rainfall and the occurrence of conidia on any of the bark samples. A laboratory study was conducted to determine whether conidia from M. anisopliae fungal bands could be spread to other parts of the environment by A. glabripennis adults and whether A. glabripennis could become infected by conidia dispersed from fungal bands. One or five adult A. glabripennis were used to contaminate artificial environments with conidia. All adults subsequently exposed to contaminated environments were killed by fungal infection. Beetles exposed to environments that had been contaminated by five beetles died in fewer days compared with environments contaminated by one beetle. Beetles in both density treatments died in fewer days than beetles exposed to environments without M. anisopliae conidia. Our results indicate that environmental contamination with conidia from fungal bands can occur, and that adult A. glabripennis can acquire infection from a contaminated environment.
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