1 University of Pittsburgh Graduate School of Public Health Academic Consortium for Excellence in Environmental Public Health Tracking (UPACE- EPHT) Can

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University of PittsburghGraduate School of Public Health

Academic Consortium for Excellence in Environmental Public Health Tracking (UPACE-

EPHT)

Can the Concept of Environmental Public Health Tracking Work in a

Real Life Setting?

Evelyn Talbott, DrPH, MPH

January 31, 2006

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National Environmental Public Health Tracking Network

• Institute of Medicine (1988) noted that “the removal of environmental health authority from public health agencies has led to fragmented responsibility, lack of coordination, and inadequate attention to the health dimensions of environmental problems.”

• In 2001, the Pew Environmental Health Commission issued the report “America’s Environmental Health Gap: Why the Country Needs a Nationwide Health Tracking Network”, which stated that “the existing environmental health system is neither adequate nor well organized, recommended the creation of a Nationwide Health Tracking Network for disease and exposures.”

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National Environmental Public Health Tracking Network

• In fiscal year 2002, Congress provided CDC with funding of $17.5 million to do the following:

– begin developing a nationwide environmental public health tracking network

– develop capacity in environmental health within state and local health departments.

• Several state and local health departments, and universities were funded to build capacity in environmental health

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University of Pittsburgh/Drexel University Environmental Public Health Academic Partner

(Consortium) Overview

• “…uniquely positioned to broaden resource coverage for public health agencies in the northeastern corridor and across the nation…”

• “…and to act as an academic partner in a local, state, regional and national initiative to facilitate environmental capacity building, to evaluate existing surveillance methodologies and to develop and/or extend innovative strategies and tools to link hazards, exposures and health effects databases.”

• “…participate in the development and/or modification of easily accessible, web-based applications for environmental health tracking, disease surveillance and data linkage by public health agency personnel…”

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Hazard databases: TRI, EPA air toxics, water quality measures, etc.

Exposure databases:Biomonitoring information-Blood lead, arsenic, mercury,etc.

Data linkage strategies

Environmental Public Health Tracking Network:Data Acquisition and Linkage: The Challenge

Health outcomes databases: Mortality, morbidity (admissions, ED visits, officevisits, medication usage, etc)

Evaluate associations

Direct Research and Interventions

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Can the Concept of Environmental Public Health Tracking Work in a Real Life

Setting?

• The question remains, at the end of this major effort, will the Environmental Public Health Tracking Network be able to track and link hazards, exposures and outcomes in a way that will have real life effects and impact on the public health of our communities?

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Setting?

• Moreover, will investigators be able to establish new relationships between environmental hazards and disease?

• Perhaps most importantly, will public health professionals have the ability to intervene upon these conditions to make a difference?

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Setting?

• The two primary objectives of the nationwide health tracking are to:

• 1) Identify populations at risk and respond to outbreaks, clusters, and emerging threats and

• 2) Establish the relationship between environmental hazards and disease

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Setting?

• At the heart of a national surveillance and tracking system is the context of “Who” and “What” to track.

• It is unrealistic to think each citizen will wear a personal monitor for every potential pollutant and a companion biomonitoring device that would detect an enhanced body burden.

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Setting?

• The second best design for a national surveillance system is that which takes advantage of a common area and population, linking variables which share similar time, and space coordinates. An example of time, person and place are the hallmarks of epidemiological investigations.

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Setting?

• These “ecological studies” are often used to consider the trends of disease over time in a certain population or cohort and are hypothesis generating investigations .

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Setting?

• In ecologic studies, the group rather than the individual is the unit of comparison.

• Disease rates in various groups, usually defined as a group living within specific geographic areas are compared.

• The variation in rates from one area to another may be explained by correlations between these rates and risk factors or “exposures” distinct to certain areas.

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Setting?

• These studies are constrained by the use of group rates of disease or hospitalizations as well as area –wide averages of hazard exposure measures.

• Linkage is by way of census tract, geocode, Zip code or county.

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Setting?

• The data are often available in electronic format and de-identified, making linkage of both the hazard/ environmental exposure and the outcome feasible.

• Emergency room visits and admissions, hospitalizations, data from cancer registries, etc offer significant potential for such ecological investigations.

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Setting?

• What examples currently exist that show that ecological studies have utility in the EPHT mode?

• Examples of ecological studies which have

yielded important information on an exposure and outcome are available in the literature; however most have been conducted within the context of a research study.

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Setting?

• Investigators obtain the necessary data on confounders within a disease-exposure relationship.

• Confounders are risk factors which if present can affect both exposure and outcome.

• Pancreatic cancer has been linked to cigarette smoking; however, heavy cigarette smoking is often related to heavy coffee drinking.

• If one does not control for cigarette smoking, coffee intake would arise as a significant risk factor.

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Setting? • Another classic example is that of the effect of age

of a population on chronic disease mortality rates.

• Cancer rates increase exponentially as we age. If there are two communities with vastly different age distributions, one community will appear to be riddled with higher rates of disease when in reality the age difference is the defining factor

• Age adjustment should have been carried out prior to the comparison.

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Setting? • The combination of a deliberate and

thoughtful consideration of the rationale for the study as well as adjustment for confounders takes time

• In the case of surveillance, access to sufficient data might be limited.

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Setting? • Problems related to misinterpretation can be

avoided if the age, race and gender distribution of a population are known and a large enough sample size is available for study.

• Moreover, access to detailed census information on the area under investigation and careful consideration of the area of exposure will help ensure the most specificity of representation of the exposure to the exposed population.

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Examples of Public Health Tracking in a Real Life Setting

• In 1990 Arden Pope was able to obtain hospitalization admission data on pulmonary and cardiovascular outcomes in children and adults related to a steel mill in the area which had ceased operation for a discrete period of time.

• A precipitous drop occurred in the number of hospitalizations (25%) during closure with an increase in rates and numbers when the plant reopened.

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Number of Hospital Inpatient Admissions

for Selected Respiratory Diseases in Children Ages 0-17Utah Valley, Utah across Time Periods with Geneva Steel Mill Open and Closed

1985-1988 Winter Months (December-February)(from data in Pope CA, AJPH 1989; 79:623-628.

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30

40

50

60

70

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Nu

mb

er

of

Ho

sp

ita

l A

dm

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1985/86 (Mill Open)Mean PM10=90

1986/87 (Mill Closed)Mean PM10=51

1987/88 (Mill Open)Mean PM10=84

Bronchitis/Asthma Ages 0-17 Pneumonia/Pleurisy Ages 0-17

Figure 1

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• Another example is the now famous decrement in blood lead levels in the late 1970’s as a result of the removal of lead from gasoline.

• The EPA ruling in l975 resulted in the removal of lead in gasoline for all noncommercial vehicles

• The result of this removal was 37% decrease in average blood levels in the U.S. from February l976 through February l980.

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An additional example is related to aeroallergens and pollen counts in a defined area as related to childhood asthma exacerbations. Such evidence can provide an intervention strategy in a defined neighborhood or municipality.

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Risk Ratios of asthma admissions and ER visits by level / type of pollen

Clinical and Experimental Allergy, 2000, Volume 30, 1724-1732

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Setting?

They are very powerful examples because they illustrate that our environment has important effects on our well being.

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These examples of ecological studies demonstrate that for a given group of subjects, when the “pollutant” in question was removed or reduced, a concomitant reduction in a biological response (biomarker of exposure) (in this case blood lead levels) or health outcome (reduction in hospital admissions for asthma/ respiratory illnesses) occurred.

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Setting?

. The ecological design just described must be viewed in the context of several important pitfalls. When using data on group rates and group exposures, a major issue is one of defining the true “exposed population” and “exposed area”.

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Setting?

Within a given county there may be varying levels of an air pollutant which is dependent upon topography and wind direction and the differences in exposure levels among subgroups of sensitive populations may not provide adequate sample size to quantify the response to such an exposure

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Setting?

• What alternatives does an environmental public health tracking network offer in such cases?

• Biomonitoring of unique and/or sensitive subsets of the population is one way to help target groups more likely to be affected by an exposure. Moreover, when a unique exposure occurs in more than one locale, a national tracking program would have the ability to link this information for multiple sites.

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Setting?

• Can the concept of the Environmental Public Health Tracking work in a real life setting?

• The answer is an unqualified “Yes”, given appropriate cooperation from participating states and city health departments and the ability to link high quality data on hazards, exposures and

outcomes.

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Setting?

• The EPHTN has the potential to yield important new information on the risk factors and environmental triggers that have remained elusive for a number of chronic diseases and conditions.

• The ability to link hazards and exposures to disease endpoints in a responsible way is a critical step in the protection of our nation’s public health.

Documents

1 University of Pittsburgh Graduate School of Public Health Academic Consortium for Excellence in Environmental Public Health Tracking (UPACE- EPHT) Can