Search

Background: Studies of air pollution exposure and arterial stiffness have reported inconsistent results and large studies employing the reference standard of arterial stiffness, carotid-femoral pulse-wave velocity (CFPWV), have not been conducted., Aim: To study long-term exposure to ambient fine particles (PM 2.5 ), proximity to roadway, and short-term air pollution exposures in relation to multiple measures of arterial stiffness in the Framingham Heart Study., Methods: We assessed central arterial stiffness using CFPWV, forward pressure wave amplitude, mean arterial pressure and augmentation index. We investigated long-and short-term air pollution exposure associations with arterial stiffness with linear regressions using long-term residential PM 2.5 (2003 average from a spatiotemporal model using satellite data) and proximity to roadway in addition to short-term averages of PM 2.5 , black carbon, particle number, sulfate, nitrogen oxides, and ozone from stationary monitors., Results: We examined 5842 participants (mean age 51 ± 16, 54% women). Living closer to a major roadway was associated with higher arterial stiffness (0.11 m/s higher CFPWV [95% CI: 0.01, 0.22] living <50 m vs 400 ≤ 1000 m). We did not observe association between arterial stiffness measures and long-term PM 2.5 or short-term levels of PM 2.5 , particle number, sulfate or ozone. Higher levels of black carbon and nitrogen oxides in the previous days were unexpectedly associated with lower arterial stiffness., Conclusions: Long-term exposure to PM 2.5 was not associated with arterial stiffness but positive associations with living close to a major road may suggest that pollutant mixtures very nearby major roads, rather than PM 2.5 , may affect arterial stiffness. Furthermore, short-term air pollution exposures were not associated with higher arterial stiffness., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: Residential proximity to green space has been associated with physical and mental health benefits, but whether green space is associated with post-stroke survival has not been studied., Methods: Patients ≥ 21 years of age admitted to the Beth Israel Deaconess Medical Center (BIDMC) between 1999 and 2008 with acute ischemic stroke were identified. Demographics, presenting symptoms, medical history and imaging results were abstracted from medical records at the time of hospitalization for stroke onset. Addresses were linked to average Normalized Difference Vegetation Index, distance to roadways with more than 10,000 cars/day, and US census block group. Deaths were identified through June 2012 using the Social Security Death Index., Results: There were 929 deaths among 1645 patients with complete data (median follow up: 5 years). In multivariable Cox models adjusted for indicators of medical history, demographic and socioeconomic factors, the hazard ratio for patients living in locations in the highest quartile of green space compared to the lowest quartile was 0.78 (95% Confidence Interval: 0.63-0.97) (p-trend = 0.009). This association remained statistically significant after adjustment for residential proximity to a high traffic road., Conclusions: Residential proximity to green space is associated with higher survival rates after ischemic stroke in multivariable adjusted models. Further work is necessary to elucidate the underlying mechanisms for this association, and to better understand the exposure-response relationships and susceptibility factors that may contribute to higher mortality in low green space areas., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Rationale: Short-term exposure to ambient air pollution has been associated with lower lung function. Few studies have examined whether these associations are detectable at relatively low levels of pollution within current U.S. Environmental Protection Agency (EPA) standards., Objectives: To examine exposure to ambient air pollutants within EPA standards and lung function in a large cohort study., Methods: We included 3,262 participants of the Framingham Offspring and Third Generation cohorts living within 40 km of the Harvard Supersite monitor in Boston, Massachusetts (5,358 examinations, 1995-2011) who were not current smokers, with previous-day pollutant levels in compliance with EPA standards. We compared lung function (FEV1 and FVC) after previous-day exposure to particulate matter less than 2.5 μm in diameter (PM2.5), nitrogen dioxide (NO2), and ozone (O3) in the "moderate" range of the EPA Air Quality Index to exposure in the "good" range. We also examined linear relationships between moving averages of pollutant concentrations 1, 2, 3, 5, and 7 days before spirometry and lung function., Measurements and Main Results: Exposure to pollutant concentrations in the "moderate" range of the EPA Air Quality Index was associated with a 20.1-ml lower FEV1 for PM2.5 (95% confidence interval [CI], -33.4, -6.9), a 30.6-ml lower FEV1 for NO2 (95% CI, -60.9, -0.2), and a 55.7-ml lower FEV1 for O3 (95% CI, -100.7, -10.8) compared with the "good" range. The 1- and 2-day moving averages of PM2.5, NO2, and O3 before testing were negatively associated with FEV1 and FVC., Conclusions: Short-term exposure to PM2.5, NO2, and O3 within current EPA standards was associated with lower lung function in this cohort of adults.

Background: Living in areas with higher levels of ambient air pollution has been associated with a higher incidence of ischemic stroke and all-cause mortality but less is known about the relationship between traffic-related pollution and long-term survival after stroke., Methods: We identified consecutive patients admitted to Beth Israel Deaconess Medical Center with ischemic stroke between 1999 and 2008 and determined the distance to the nearest roadway with an average daily traffic count of more than 10,000 vehicles/day. Categories of residential proximity were defined as 100 m or less, 100-200 m, 200-400 m or less, or more than 400 m from a busy roadway. We identified deaths through June 2012 using the Social Security Death Index and used Cox proportional hazards models adjusted for medical history and socioeconomic factors to calculate hazard ratios for the association between residential proximity to a high-traffic roadway and all-cause mortality., Results: Among 1683 stroke patients with complete data, there were 950 deaths (median follow-up=4.6 years). We observed higher poststroke mortality among people living closer to high-traffic roadways. Patients living 100 m or less from high-traffic roadways had a 20% (95% confidence interval: 1%, 43%) higher rate of poststroke mortality than patients living more than 400 m away (P trend=.02)., Conclusions: In this study, living close to a high-traffic roadway was associated with an elevated mortality rate. This relationship remained statistically significant after adjustment for individual- and neighborhood-level factors, providing evidence that traffic-related pollution is associated with a higher mortality rate among stroke survivors., (Copyright © 2013 National Stroke Association. Published by Elsevier Inc. All rights reserved.)

Background: Evidence suggests that air pollution is associated with atherosclerosis and that traffic-related particles are a particularly important contributor to the association., Objectives: We investigated the association between long-term exposure to black carbon, a correlate of traffic particles, and intima-media thickness of the common carotid artery (CIMT) in elderly men residing in the greater Boston, Massachusetts, area., Methods: We estimated 1-year average exposures to black carbon at the home addresses of Normative Aging Study participants before their first CIMT measurement. The association between estimated black carbon levels and CIMT was estimated using mixed effects models to account for repeated outcome measures. In secondary analyses, we examined whether living close to a major road or average daily traffic within 100 m of residence was associated with CIMT., Results: There were 380 participants (97% self-reported white race) with an initial visit between 2004 and 2008. Two or three follow-up CIMT measurements 1.5 years apart were available for 340 (89%) and 260 (68%) men, respectively. At first examination, the average ± SD age was 76 ± 6.4 years and the mean ± SD CIMT was 0.99 ± 0.18 mm. A one-interquartile range increase in 1-year average black carbon (0.26 µg/m3) was associated with a 1.1% higher CIMT (95% CI: 0.4, 1.7%) based on a fully adjusted model., Conclusions: Annual mean black carbon concentration based on spatially resolved exposure estimates was associated with CIMT in a population of elderly men. These findings support an association between long-term air pollution exposure and atherosclerosis.

Background: Living near major roadways has been associated with increased risk of cardiovascular events, but little is known about its impact on renal function., Methods: We calculated the estimated glomerular filtration rate (eGFR) for 1103 consecutive Boston-area patients hospitalised with confirmed acute ischaemic stroke between 1999 and 2004. We used linear regression to evaluate the association between eGFR and categories of residential distance to major roadway (0 to ≤50, >50 to ≤100, >100 to ≤200, >200 to ≤400, >400 to ≤1000 and >1000 m) adjusting for age, sex, race, smoking, comorbid conditions, treatment with ACE inhibitor and neighbourhood-level socioeconomic characteristics. In a second analysis, we considered the log of distance to major roadway as a continuous variable., Results: Patients living closer to a major roadway had lower eGFR than patients living farther away (Ptrend=0.01). Comparing patients living 50 m versus 1000 m from a major roadway was associated with a 3.9 ml/min/1.73 m(2) lower eGFR (95% CI 1.0 to 6.7; p=0.007): a difference comparable in magnitude to the reduction in eGFR observed for a 4-year increase in age in population-based studies. The magnitude of this association did not differ significantly across categories of age, sex, race, history of hypertension, diabetes or socioeconomic status., Conclusions: Living near a major roadway is associated with lower eGFR in a cohort of patients presenting with acute ischaemic stroke. If causal, these results imply that exposures associated with living near a major roadway contribute to reduced renal function, an important risk factor for cardiovascular events.

Background: Extreme temperatures have been associated with hospitalization and death among individuals with heart failure, but few studies have explored the underlying mechanisms., Objectives: We hypothesized that outdoor temperature in the Boston, Massachusetts, area (1- to 4-day moving averages) would be associated with higher levels of biomarkers of inflammation and myocyte injury in a repeated-measures study of individuals with stable heart failure., Methods: We analyzed data from a completed clinical trial that randomized 100 patients to 12 weeks of tai chi classes or to time-matched education control. B-type natriuretic peptide (BNP), C-reactive protein (CRP), and tumor necrosis factor (TNF) were measured at baseline, 6 weeks, and 12 weeks. Endothelin-1 was measured at baseline and 12 weeks. We used fixed effects models to evaluate associations with measures of temperature that were adjusted for time-varying covariates., Results: Higher apparent temperature was associated with higher levels of BNP beginning with 2-day moving averages and reached statistical significance for 3- and 4-day moving averages. CRP results followed a similar pattern but were delayed by 1 day. A 5°C change in 3- and 4-day moving averages of apparent temperature was associated with 11.3% [95% confidence interval (CI): 1.1, 22.5; p = 0.03) and 11.4% (95% CI: 1.2, 22.5; p = 0.03) higher BNP. A 5°C change in the 4-day moving average of apparent temperature was associated with 21.6% (95% CI: 2.5, 44.2; p = 0.03) higher CRP. No clear associations with TNF or endothelin-1 were observed., Conclusions: Among patients undergoing treatment for heart failure, we observed positive associations between temperature and both BNP and CRP-predictors of heart failure prognosis and severity.