EDF Health

Estimating chemical risk: Breadth (prevalence) may be just as important as depth (magnitude of effect)

Jennifer McPartland, Ph.D., is a Health Scientist.

Earlier this month Dr. David Bellinger at Boston Children’s Hospital published a very interesting paper in Environmental Health Perspectives offering a new way to consider the importance of various risk factors for child neurodevelopment—such as pre-existing medical conditions, poor nutritional status or harmful chemical exposures—at the population level.  “A Strategy for Comparing the Contributions of Environmental Chemicals and Other Risk Factors to Neurodevelopment of Children” argues that, in evaluating the contribution of a risk factor to a health outcome, it is critical to consider not only the magnitude of its effect on the health outcome, but also the prevalence of that risk factor in the population.

Dr. Bellinger argues: “Although a factor associated with a large impact would be a significant burden to a patient, it might not be a major contributor to the population if it occurs rarely.  Conversely, a factor associated with a modest but frequently occurring impact could contribute significantly to population burden.”  The former “disease-oriented” approach has generally been used to estimate the burden of harmful chemical exposures to population health, rather than the latter “population-oriented” approach.  Relying solely on the former approach, he contends, may result in an underestimation of the impact of a chemical exposure or other risk factor on public health.  Read More »

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Exposing our ignorance: EPA study reveals barren exposure data landscape

Jennifer McPartland, Ph.D., is a Health Scientist.

This past November, EPA scientists published a sobering paper, “The exposure data landscape for manufactured chemicals,” in the journal Science of the Total Environment.  The paper reveals how little systematic information we have about human and environmental exposures to the thousands of chemicals in use today.

The aim of the study was “to define important aspects of the [chemical] exposure space and to catalog the available exposure information for chemicals being considered for analysis as part of the U.S. EPA ToxCast screening and prioritization program.”  Its conclusion:  “The results suggest that currently available exposure data are insufficient to provide the evidence base required to inform risk assessment and public health decision making.”  Not good, but not surprising.  Read on for more detail. Read More »

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Twin dangers from TCE: Widespread exposure, and now a strong link to Parkinson disease

Jennifer McPartland, Ph.D., is a Health Scientist.

A study published online in the Annals of Neurology last week, “Solvent Exposures and Parkinson Disease Risk in Twins,” adds to scientific evidence linking exposure to the solvent trichloroethylene, or TCE, and other common solvents with onset of Parkinson disease.  Parkinson disease is a debilitating condition well known for symptoms of trembling but can also include slowed motion, impaired posture and balance, and loss of automatic movements (e.g. blinking, arm swaying when walking).  Most unfortunately, it has no cure. 

According to the authors, this new twin study is the first confirmation in a population-based study of a significant association between exposure to TCE and incidence of Parkinson disease.    Read More »

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Gasping for breath: Asthma-inducing diisocyanates enter our homes and schools

Johanna Katz is a Cornell Iscoll intern at EDF.  Jennifer McPartland, Ph.D., is a Health Scientist.

Toxic chemicals called diisocyanates are long-established as occupational hazards known to cause severe respiratory problems to workers who use or are otherwise exposed to them (see here).  In fact, diisocyanates are the number one cause of workplace-induced asthma (see here and here).  Recently, potential exposure of the general public to diisocyanates has grown, as these chemicals are increasingly used in consumer products.  This is certainly a troubling trend considering that the primary health effect of these chemicals, asthma, is a massive and growing public health problem, especially among children.  And some of the newest uses of diisocyanates are in products to which children are quite likely to be exposed.

Asthma is at an all-time high, affecting more than 24 million Americans, and creating astronomical health and productivity costs upwards of $20 BILLION each year.  And while diisocyanates are but one of many contributors to the increasing rate of asthma in the general population, we surely don’t need to be bringing more products containing such chemicals into our homes, schools, and workplaces. That will only make matters worse.

So what exactly are diisocyanate chemicals, where are they found, and what’s the federal government trying to do about them?  Read on to find out.  Read More »

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Chemical safety evaluation: Limitations of emerging test methods

Jennifer McPartland, Ph.D., is a Health Scientist. Richard Denison, Ph.D., is a Senior Scientist.

Parts in this series:      Part 1     Part 2     Part 3     Part 4

This is the fourth in a series of blog posts on new approaches that federal agencies are exploring to improve how chemicals are evaluated for safety.  In this post, we’ll discuss a number of current limitations and challenges that must be overcome if the new approaches are to fulfill their promise of transforming the current chemical safety testing paradigm.  Read More »

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Chemical safety evaluation: Potential benefits of emerging test methods

Jennifer McPartland, Ph.D., is a Health Scientist.

Parts in this series:      Part 1     Part 2     Part 3     Part 4

This is the third in a series of blog posts on new approaches that federal agencies are exploring to improve how chemicals are evaluated for safety.  Previous posts primarily focused on the scientific principles underlying these efforts.  This post will take a pause from scientific fundamentals to discuss some of the opportunities presented by these more novel methods, while subsequent posts will address some of their limitations and remaining challenges.  (Not to worry, though, I’ll soon get back to computer-simulated organs as promised.)  Read More »

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