116 research outputs found
Recommended from our members
Measurement error in environmental exposures: Statistical implications for spatial air pollution models and gene environment interaction tests
No full textMeasurement error is an important issue in studies of environmental epidemiology. We considered the effects of measurement error in environmental covariates in several important settings affecting current public health research. Throughout this dissertation, we investigate the impacts of measurement error and consider statistical methodology to fix that error
Ambient pollutants, polymorphisms associated with microRNA processing and adhesion molecules: the Normative Aging Study
No full textAbstract Background Particulate air pollution has been associated with cardiovascular morbidity and mortality, but it remains unclear which time windows and pollutant sources are most critical. MicroRNA (miRNA) is thought to be involved in cardiovascular regulation. However, little is known about whether polymorphisms in genes that process microRNAs influence response to pollutant exposure. We hypothesized that averaging times longer than routinely measured one or two day moving averages are associated with higher soluble intercellular adhesion molecule-1 (sICAM-1) and vascular cell adhesion molecule-1 (sVCAM-1) levels, and that stationary and mobile sources contribute differently to these effects. We also investigated whether single nucleotide polymorphisms (SNPs) in miRNA-processing genes modify these associations. Methods sICAM-1 and sVCAM-1 were measured from 1999-2008 and matched to air pollution monitoring for fine particulate matter (PM2.5) black carbon, and sulfates (SO42-). We selected 17 SNPs in five miRNA-processing genes. Mixed-effects models were used to assess effects of pollutants, SNPs, and interactions under recessive inheritance models using repeated measures. Results 723 participants with 1652 observations and 1-5 visits were included in our analyses for black carbon and PM2.5. Sulfate data was available for 672 participants with 1390 observations. An interquartile range change in seven day moving average of PM2.5 (4.27 μg/m3) was associated with 3.1% (95%CI: 1.6, 4.6) and 2.5% (95%CI: 0.6, 4.5) higher sICAM-1 and sVCAM-1. Interquartile range changes in sulfates (1.39 μg/m3) were associated with 1.4% higher (95%CI: 0.04, 2.7) and 1.6% (95%CI: -0.4, 3.7) higher sICAM-1 and sVCAM-1 respectively. No significant associations were observed for black carbon. In interaction models with PM2.5, both sICAM-1 and sVCAM-1 levels were lower in rs1062923 homozygous carriers. These interactions remained significant after multiple comparisons adjustment. Conclusions PM2.5 seven day moving averages are associated with higher sICAM-1 and sVCAM-1 levels. SO4-2 seven day moving averages are associated with higher sICAM-1 and a suggestive association was observed with sVCAM-1 in aging men. SNPs in miRNA-processing genes may modify associations between ambient pollution and sICAM-1 and sVCAM-1, which are correlates of atherosclerosis and cardiovascular disease.</p
Environ Health Perspect
No full textTraffic-related particles (TRPs) are associated with adverse cardiovascular events. The exact mechanisms are unclear, but systemic inflammatory responses likely play a role.|We conducted a repeated measures study among male participants of the Normative Aging Study in the greater Boston, Massachusetts, area to determine whether individual-level residential black carbon (BC), a marker of TRPs, is associated with systemic inflammation and whether coronary heart disease (CHD), diabetes, and obesity modify associations.|We quantified markers of inflammation in 1,163 serum samples from 580 men. Exposure to BC up to 4 weeks prior was predicted from a validated spatiotemporal land-use regression model. Linear mixed effects models estimated the effects of BC on each marker while adjusting for potential confounders.|Associations between BC and blood markers were not observed in main effects models or when stratified by obesity status. However, BC was positively associated with markers of inflammation in men with CHD (particularly vascular endothelial growth factor) and in men with diabetes (particularly interleukin-1\uce\ub2 and tumor necrosis factor-\uce\ub1). Significant exposure time windows varied by marker, although in general the strongest associations were observed with moving averages of 2-7 days after a lag of several days.|In an elderly male population, estimated BC exposures were positively associated with markers of systemic inflammation but only in men with CHD or diabetes.1R01 ES014663-01A2/ES/NIEHS NIH HHS/United StatesT42 OH008416-04/OH/NIOSH CDC HHS/United States22336131PMC334677
Impact of 2012 USPSTF prostate cancer screening recommendations on prostate cancer detection and presentation at Kaiser Permanente Northern California (KPNC).
No full text 37 Background: In 2012, the USPSTF gave a “D” grade to PSA-based prostate cancer screening stating “the benefits of PSA-based screening for prostate cancer do not outweigh the harms”. The impact on prostate cancer screening, detection and presentation are unknown. Methods: A retrospective cohort design encompassing the years 2010 to 2015. In screen-eligible, KPNC members (African American men ages 45-69 and all other men ages 50-69), the annual rates of PSA testing, prostate biopsy and the grade and stage of all prostate cancers at presentation were compared between the pre-guideline period, 2010/2011; and the post-guideline period , 2014/2015. Results: The rate of screening declined substantially from the pre-guideline period to the post-guideline period, from a rate of 42.7% of eligible men screened per year during 2010/2011 to a rate of 32.5% of eligible men screened per year during 2014/2015; the relative rate and 95% confidence interval (CI) was 0.762 (0.759-0.765). Comparing the same time periods, the rates of prostate biopsy and overall prostate cancer detection declined even more sharply, with relative rates of 0.391 (95%CI 0.375-0.407) and 0.455 (95%CI 0.436-0.475) respectively. There was a modest increase in the rate of metastatic disease between these two time periods, with a relative rate of 1.29 (95%CI 1.11-1.48). Conclusions: Following the 2012 USPSTF statement, significant declines in PSA testing, prostate biopsy and overall cancer detection rates were seen along with a significant increase in the rate of patients presenting with metastatic disease. [Table: see text] </jats:p
Spatial measurement error and correction by spatial SIMEX in linear regression models when using predicted air pollution exposures
No full text© 2015 The Author 2015. Published by Oxford University Press. All rights reserved. Spatial modeling of air pollution exposures is widespread in air pollution epidemiology research as a way to improve exposure assessment. However, there are key sources of exposure model uncertainty when air pollution is modeled, including estimation error and model misspecification. We examine the use of predicted air pollution levels in linear health effect models under a measurement error framework. For the prediction of air pollution exposures, we consider a universal Kriging framework, which may include land-use regression terms in the mean function and a spatial covariance structure for the residuals. We derive the bias induced by estimation error and by model misspecification in the exposure model, and we find that a misspecified exposure model can induce asymptotic bias in the effect estimate of air pollution on health. We propose a new spatial simulation extrapolation (SIMEX) procedure, and we demonstrate that the procedure has good performance in correcting this asymptotic bias. We illustrate spatial SIMEX in a study of air pollution and birthweight in Massachusetts
Association between long-term exposure to traffic particles and blood pressure in the Veterans Administration Normative Aging Study
No full textParticulate air pollution is associated with cardiovascular events, but the mechanisms are not fully understood. The main objective was to assess the relationship between long-term exposure to traffic-related air pollution and blood pressure (BP)
Validation of an Algorithm to Identify Ectopic Pregnancy in a Large Integrated Health Care Delivery System Database [40N]
No full text
- …
