2012 — 2016 |
Wellenius, Gregory A |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Ambient Air Pollution and Incident Stroke
DESCRIPTION (provided by applicant): There is a well-documented association between cardiovascular disease morbidity and mortality and increased levels of ambient fine particulate air pollution (PM2.5). Stroke is a common manifestation of cardiovascular disease and a leading cause of death, hospitalization, and long-term disability in the United States. PM2.5 may also increase the risk of ischemic and/or hemorrhagic stroke, but few studies have specifically addressed this hypothesis and results remain equivocal. Other important gaps in this literature include: identification of especially susceptible individuals; evaluation of the effects of PM2.5 component species, gaseous pollutants (CO, NO2, SO2, and ozone) and specific air pollution sources; and delineation of the time scale of effects. We propose to evaluate in unprecedented detail the association between exposure to individual ambient pollutants and pollutant mixtures and the risk of stroke among 159,643 post-menopausal women participating in the Women's Health Initiative and 45,358 men participating in the Health Professionals Follow-Up Study. Specifically, using data from these two national, prospective cohorts we will: (1) evaluate the effects of long- term (i.e.: years) and short-term (i.e.: days) exposure to ambient pollutants on the risk of ischemic and hemorrhagic stroke, (2) assess whether participants with diabetes mellitus and other stroke risk factors are especially susceptible to these effects, (3) examine whether the strength of association varies by ischemic stroke subtypes, and (4) evaluate these associations within a novel multi-pollutant framework. To accomplish these aims we will estimate each participant's exposure to PM2.5, PM2.5 component species, gaseous pollutants, and pollutant mixtures using validated state-of-the-art geostatistical models, and relate each individual's exposure to the risk of ischemic and hemorrhagic stroke. This proposal offers several advantages over existing studies, including two well characterized study populations, detailed data on each stroke event, large sample size, geographic diversity, the ability to examine short-term and long-term effects jointly, novel statistical methods to reduce measurement error, and the opportunity to assess multiple pollutants simultaneously within a novel multi-pollutant framework. By better quantifying the relationship between ambient air pollutants and pollution mixtures and specific stroke types, and by identifying susceptible populations, the results of this project will contribute to regulatory policy with important implications for stroke prevention, and may help to inform the planning of future mechanistic studies. PUBLIC HEALTH RELEVANCE: Stroke is a leading cause of death, hospitalization, and disability in the United States. Studies suggest that exposure to outdoor air pollution may increase the risk of stroke, but this hypothesis has not been evaluated in detail. We propose to use novel methods and approaches to evaluate this hypothesis in detail within the context of two large, national studies including 161,000 post-menopausal women and 51,000 men. The results of this project will likely have important implications for stroke prevention through futur changes in public health policy.
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0.923 |
2013 — 2014 |
Wellenius, Gregory A |
R21Activity Code Description: To encourage the development of new research activities in categorical program areas. (Support generally is restricted in level of support and in time.) |
Residential Air Pollution and Preeclampsia
DESCRIPTION (provided by applicant): Preeclampsia is a disease characterized by new onset of hypertension and proteinuria during the second half of pregnancy, affecting 3-8% of pregnancies. It is a leading cause of maternal and fetal morbidity and mortality, and delivery remains the only known treatment.!Fine particulate matter (PM2.5) air pollution has been persuasively linked to increased risk of cardiovascular morbidity and mortality, with pollution from traffic identified as a key source. Maternal exposure to air pollution may also be associated with slower fetal growth, lower birth weight, and higher risk of preterm birth and small size for gestational age at birth. Preeclampsia is one of the leading causes of preterm birth and small size for gestational age, and thus may be an early event leading to these outcomes. However, few studies have evaluated the association between air pollution and risk of preeclampsia. To rigorously address this hypothesis, we propose a novel two-pronged approach consisting of: 1) a large cohort study based on detailed administrative and vital records data on 88,000 singleton births between 2002 and 2011 at the Women and Infants Hospital of Rhode Island, including >4,000 patients with a discharge diagnosis of preeclampsia, and 2) a large, case-control study (1000 cases/1000 controls) nested within this cohort with detailed review of medical records from prenatal care to delivery to obtain, for the first time, data on: a) maternal residential histry throughout the pregnancy, and b) clinical features and timing of onset of preeclampsia. In both studies we will estimate residential exposure to PM2.5 throughout pregnancy using a novel, high-resolution (1 km grid) spatial-temporal model informed by both satellite and ground based monitoring, and residential exposure to pollution derived from traffic sources by extending our validated spatial-temporal model of black carbon. Thus, the proposed project combines the strongest features of previous studies and offers novel refinements. Given ubiquitous exposure to ambient air pollution, the public health importance of preeclampsia, suggestive preliminary epidemiologic evidence, and the biologic plausibility of a link between exposure and preeclampsia, this hypothesis warrants further evaluation with improved methods for assessing exposures, health outcomes, and their interrelationships.
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0.923 |
2019 — 2020 |
Wellenius, Gregory A |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Evidence to Improve Heat Warning Effectiveness in Reducing Morbidity and Mortality
Project Summary/Abstract While exposure to high ambient temperature (i.e., heat) has long been recognized as a threat to public health, the burden of illness and death attributable to heat in the US remains high. In an effort to reduce heat- related mortality and morbidity, the US National Weather Service (NWS) issues heat alerts in advance of forecasted extreme heat events to communicate these risks to the public and government officials. However, it is largely unknown: (1) what are the optimal metrics of heat stress to inform when to issue heat alerts, (2) how effective are heat alerts in protecting the public?s health and (3) what factors make heat alerts comparatively more or less effective in some places or in some people versus others. In the absence of such information, we will fail to maximize the public health benefits of heat alerts. The goals of this proposal are to identify the optimal health-based and location-specific metrics for issuing heat alerts, to estimate the causal benefits of heat alerts, and to identify characteristics of individuals or communities associated with the greatest reductions in morbidity or mortality following heat alerts. Specifically, using national claims data on deaths and hospital admissions among the large, geographically diverse population of >60 million US Medicare beneficiaries age ?65 years enrolled between 2001 and 2015, and on emergency department visits among >130 million participants of all ages from one of the nation?s largest health insurers, we propose to: (Aim 1) Use novel machine learning methods to identify the heat metric(s) (e.g., heat index, ambient temperature, spatial synoptic classification, wet bulb globe temperature, absolute humidity) that best predict excess heat-related deaths, emergency hospitalizations, and emergency departments visits in each location, (Aim 2) estimate the causal effects of NWS heat alerts on rates of mortality, hospitalizations, and emergency department visits across the country and within groups stratified by health outcome, sex, and age group, and (Aim 3) assess how the benefits of heat alerts vary across characteristics of communities. Key innovations of this proposal include a very large sample size, geographic diversity encompassing the entire US, the assessment across multiple health endpoints and age groups, and the use of sophisticated methods in statistical learning and causal inference. Collectively, the findings from this proposal will provide meteorologists, public health and emergency management officials, and local policy-makers with critical information to better protect public health during extreme heat events and guide more targeted future research on strategies to mitigate the adverse health effects of heat.
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0.923 |