Is a health study the answer for your community?

Is your community concerned about PFAS pollution? You may be interested in a health study, or you may have been told that you need a health study. But is a health study right for your community — and, if so, which type of study is most appropriate? This page will help PFAS-concerned communities work through your concerns, your goals, and the details of how health studies are performed to make sure that your study serves the needs of your community.

We'll be following the outline of The Health Studies Guide from the Boston University Superfund Research Program. The Guide was written to assist community groups and individuals who think that some form of environmental health investigation or health study may be useful or necessary in their community. (Portions of the Guide are used here by permission.) While working through the questions discussed here, or after you're done, you may want to turn to the complete Guide for more details; we'll provide links to the appropriate chapters as we go.

Before getting started

Before you start considering a health study, it's a good idea to have an understanding of the basic issues. If you haven't already skimmed the Q&A on PFAS pollution, you may want to do that now, especially these questions:

For an overview of the Health Studies Guide itself, see the Introduction, p6-7.

Ready? Let's start with Chapter 1!

Chapter 1

Health Studies Guide Chapter 1

What is a health study?
Is a health study right for your community?

Before embarking on any health study, it's critical to make sure that it asks the right questions and serves your community's goals.

Chapter 1 addresses these topics:

What is a health study?

In the public health field, "health study" is a specific term for research looking at patterns of health and disease. Here, however, we'll use the term "health study" to refer to any type of study that might provide information useful to community groups concerned with health risks of environmental exposures.

Key challenges of health studies

  • Studies are meant to answer questions, but they do not necessarily give you the answer you are hoping for. A study with negative or unclear findings may work against your community's goals.
  • The clearer the study question, the more likely it is that a study will be able to address it effectively. On the other hand, in the process of sharpening one question so that it can be answered, other concerns may get lost.
  • Health studies encompass very wide range of methods and expertise. More sophisticated studies can take many years and cost many millions of dollars. In this Guide, we'll try to steer you to choosing the right type of study — or no study at all! — to reach your community's goals.
  • Some communities — for example, those with evidence of existing contamination — may not need a health study at all, or may benefit from a simpler and easier study design.

Table 1.1: Possible Impacts of a Health Study

Positive things a health study might do:

  • Document disease and/or exposure
  • Demonstrate a relationship between exposure and disease
  • Educate residents about environmental health concerns
  • Generate media coverage and motivate the community
  • Be useful for political leverage in a campaign
  • Create an opportunity for members of your community to get involved
  • Be useful in community effeorts to pretect the health of future generations
Negative things a health study might do:

  • Appear to show that there is not problem
  • Document no significant relationship between a disease and exposure
  • Give permission to polluters to continue polluting
  • Lead to legal issues over confidentiality or lawsuits by polluters
  • Be used against your campaign or group
  • Overwhelm your organizing efforts and sap members' energy
  • Generate statistics that may undermine your efforts
  • Identify health problems that you are unprepared to deal with
  • Delay action while waiting for results

Your reasons for wanting a health study

One of the first steps in determining whether a health study may be useful is to identify clearly your reasons for wanting a study. Here are two questions that will help sort out your motives:

#1. What do you want to know? That is, what is your question or concern? For example,
  • How much soot from the power plant are we breathing?
  • Is there too much illness in our community?
  • Why are people sick?
  • Is the mold in the school making our kids sick?
#2. Why do you want to know? That is, what is your goal? For example,
  • Stop the development
  • Prove we were right
  • Clean up the site
  • Get compensation

If you can answer question 1, and if your response is another question — such as the sample responses — this guide may help you identify a type of study that can answer your question. Studies are designed to answer questions, and a good study is well designed to answer your question. Even if you do not like the results, at least your question will have been addressed.

What about question 2? Why do you want to know? To answer this question you would need to have a clearly defined goal in mind. If you already have a goal, you should evaluate whether a health study of some kind can help you achieve it. It may not. Consider that a study may take much time and money and you may get results that put you farther from your goal.

Remember, the study design you choose should help you learn what you want to know so that you can better pursue your goals. A study that does not answer the correct question can be a tremendous waste of time and money.

Salem's story

Residents of Salem, Massachusetts wanted a health study to prove that the smoke from a nearby power plant was causing cancer in that community. But when the Salem study, conducted by a state agency, failed to link the power plant emissions with cancer, the power company used the study as evidence that its emissions were safe. According to residents, it was interpreted as permission to continue with "business as usual."

Questions for thought: What were Salem's goals? How else could they have advanced them?

Pollution and disease, or exposures and outcomes

Community members often express their concerns about pollution and disease: Too much pollution, too much disease, or a suspicion that disease is caused by pollution. Scientists, however, talk more abstractly about exposures and health outcomes (or just outcomes). They may also talk about "health effects" — although this term is usually reserved for cases where we understand the cause-effect relationship.

Scientists use the term exposure to refer to any chemical pollutant or other stressor (for example, radiation or mold spores) that people may encounter.

Most health outcomes are conditions that we would identify as diseases (not to be confused with the result of a study, sometimes also called the outcome). But some outcomes are more subtle than a disease. For example, a decreased level of a hormone in the body can be a health outcome, as is a slightly delayed reaction time that we wouldn't notice unless we measured it.

Connecting Exposures to Outcomes

Some health studies are limited to measuring environmental pollution or to measuring the occurrence of diseases. More sophisticated and labor-intensive studies -- which we call epidemiologic studies, and which we will discuss at length later chapters — try to measure the relationship between a specific exposure and a health outcome.

In the case of PFAS, we have a number of epidemiologic studies that connect PFAS exposures to some specific health outcomes. We also have data from animal testing that gives us hints about other possible health concerns. For more details on data about the health effects of PFAS, see Q&A: EFFECTS.

Before considering a health study, you should know what studies have already been done and what's already known. Don't reinvent the wheel! If another study has already demonstrated the link you are interested in, that may be enough information for you to advance your goals — saving you the time and expense of setting up a new study.

Remember, a health study is not the last word!

A single study rarely provides enough evidence to change scientific understanding. Science works on accumulated evidence, and since any single study could be wrong, scientists (and policy makers) are generally reluctant to draw conclusions from one study. You should not expect your health study to establish a definitive relationship between an exposure and an outcome.

In fact, even a mountain of scientific evidence is not always enough to provoke action. For example, it was first discovered that lead in children's blood was associated with learning problems decades ago, yet many, many studies were conducted before legislation was written in the United States to protect children from lead poisoning. This legislation was passed only because scientists and community members pressured politicians and executives in the lead industry to act on the scientific evidence. Science does not usually speak for itself. Only with organized community pressure and persistence will study findings be put to use.

Worksheet #1

Worksheet #1: Your Reasons for a Health Study

Download the worksheet in Microsoft Word format.

Chapter 2

Health Studies Guide Chapter 2

Your Research Question

This chapter will help you focus your concern, framing it as a research question so that it can be addressed by one of the study types described in Chapters 3 and 4. Remember, a good study is one that is designed to answer your question — so now it is time to make sure you know what question you are asking. We'll address these topics: At the end of this chapter, we'll encourage you to fill out a worksheet to help focus your study concerns and develop your research question.

Defining the problem: What is your concern?

In Chapter 1, we talked about the difference between an exposure (a pollutant or toxic substance) and a health outcome (a disease, or a condition, or even death). Now we can begin to think about whether the specific question you want answered is most related to an exposure, an outcome, or both (the exposure-outcome relationship).

A few examples might illustrate these different approaches.

Table 2.1. Examples of concerns to be addressed by a study

My concern is... My study will address...
particulates emitted by a power plant in town An exposure: Have we been exposed to something harmful?
too much breast cancer An outcome: Are there more cases here than one would expect?
possible link between kids' poor school performance and our town's old lead water pipes An exposure-outcome relationship: Is a harmful exposure affecting our health and well-being?

PFAS exposures and health outcomes

Here, we are concerned with PFAS pollution (the exposure) and the possible health outcomes that might result (the outcomes).

Exposure to PFAS will be slightly different for every person and in every community. Most Americans are exposed to "background" levels of PFAS in their diet; others may be exposed through specific jobs or activities. In most polluted communities, though, the major source of contamination is through drinking water. Therefore, we will focus primarily on PFAS exposure from contaminated drinking water.

For more background on exposure to PFAS, see Q&A: EXPOSED.

Because some PFAS chemicals have been studied, we know quite a bit about the health outcomes that are associated with them. The federal Agency For Toxic Substances and Disease Registry lists these potential health effects as being associated with PFAS exposure in humans:
  • Developmental delays in the fetus and child, including possible changes in growth, learning, and behavior;
  • Decreased fertility and changes to the body's natural hormones;
  • Increased cholesterol;
  • Changes to the immune system;
  • Increased uric acid levels;
  • Changes in liver enzymes;
  • Prostate, kidney, and testicular cancer.
For more background on health effects of PFAS, see Q&A: EFFECTS.

Defining your research question

Having considered the known PFAS routes of exposure and possible health effects, let's consider our research question again, more specifically.
  • If you are concerned about PFAS exposure, but don't yet have any data, you need to learn more about that possible exposure.

  • If you already know there is PFAS contamination in your drinking water, your community is concerned with a specific exposure. You probably want to learn more about this exposure, including details of the amount of PFAS found in water as well as in the people themselves.

  • You might also be concerned with the exposure-outcome relationship: What health effects might this known PFAS exposure be causing? This question may lead you to monitor the health of the population, to keep an eye out for possible health effects of PFAS. Study designs that address health outcomes may be useful to you. However, since you already know what specific exposure you're concerned with, you will know a lot more about what types of health outcomes to look for.

    Be careful! An epidemiologic study of your community, attempting to link your PFAS exposure to specific outcomes, is likely to be extremely expensive and time-consuming. Before embarking on a study, be sure you have considered how that study will advance your goals (see Chapter 1).

Framing Your Research Question: Who? When? Where?

Who is Your Study Population?
When Did Exposure and/or Disease Occur?
Where is Your Study Population Located?

Now you can start to answer these questions in some detail with respect to PFAS contamination in your specific community.
  • Consider who has the highest exposures. These might be people in a specific location, who receive the most contaminated water; or maybe people who drink an especially large amount of water.
  • Consider the timing of exposure. When did it start? Is it still ongoing?
  • It's important to note that not everyone is equally susceptible to these effects, consider the susceptible population. For example, developing fetuses and children are much more susceptible to the endocrine disrupting effects on the thyroid, the brain, or the immune system, since those hormonal systems are still being formed and are especially sensitive during development.
  • Keep in mind that some people may live in the community but have lower exposures (for example, if their water is filtered), while others may live elsewhere but still be exposed (for example, children from a neighboring area who attend a school with contaminated water). Define the exposed population as carefully as you can.

Considering your question with a model of exposure and disease

To pull these pieces together it may be helpful to consider your question in the context of the relationship that you think exists between the exposure and the health outcome. One way to do this is to sketch a diagram of how exposures and outcomes are generally linked (see Figure 2.1 below) and see which of these links your question addresses.

Figure 2.1: A basic model for exposure-related disease

Try to step through this model and identify your specific concerns at each step. For example:
  • Source/emissions: PFAS contamination of groundwater by runoff of firefighting foams.
  • Environmental media: PFAS infiltrates the groundwater aquifer.
  • Personal environments: Water is brought into the home via the water utility.
  • Exposure: Primarily through drinking the contaminated water. Are there other routes? For example, inhaling contaminated water in a shower is a source of exposure for some environmental contaminants.
  • Absorbed dose: This is the PFAS that enters the body and is distributed through the bloodstream.
  • Altered Tissue Structure/Biological Function and Disease: These includes all the health outcomes already discussed.
Notice that, in filling out the details above, we have concentrated only on exposure through drinking water. If you have other sources of PFAS exposure, or if you want to include (for example) dietary exposures, you should add those into your model as well — although this will make it more complicated!

Worksheet #2

Worksheet #2: Developing Your Research Question

Download the worksheet in Microsoft Word format.

Chapter 3

Health Studies Guide Chapter 3

A Menu of Health Studies

"Is there a type of study that is most appropriate for what we are trying to accomplish? Really and truly there is not... Nine out of ten, a health study will be telling you that your mind is playing tricks on you and you do not know what you are talking about."
— Emma, Resident of Louisiana

Considering the pros and cons of study types and knowing what information they can and cannot provide will help you develop a clear research strategy and avoid feeling as frustrated as Emma was. Below we have grouped some sample research questions under appropriate study types.

Study Type


(1) Mapping Studies
Exposure mapping Map(s) of exposure
Where are sources of environmental exposure located?

see Mapping Studies (HSG p39)

Exposure mapping can be done either by community groups or by scientists. It helps communities visualize sources of pollution, possibly identifying patterns of exposure. Some exposures are obvious; others will require that you get data from an environmental agency or other source. For example:
  • Some drinking water wells have been closed as a result of contamination. Where are these wells located in relation to people's homes, schools, etc.?
  • Which neighborhoods are closest to the farms where sludge is sprayed?
  • Are there childcare centers within walking distance of the highway?

What information will you need?

Outcome mapping Map(s) of disease distribution
(2) Studies of Exposure
Environmental monitoring Concentrations in environmental media
Personal monitoring Concentrations in immediate and personal surroundings
Body burden (biomonitoring) study Concentrations in bodily tissue or fluid
Environmental impact statement Description of environmental changes
(3) Studies of Outcome
Community survey Survey responses; may be qualitative
Analysis of registry data Comparison of community disease or mortality rate with standard (state, national) rate
(4) Studies of Exposure-Outcome Relationship
(Epidemiologic Studies)
Ecologic study Correlation between exposure and disease
Cohort study Relative Risk between exposed and unexposed groups
Case-control study Odds Ratio between cases (who have disease) and controls (without disease)
(5) Studies of Contaminated Sites
Risk assessment Characterization of hazard; estimates of health risk
Public health assessment Exposure evaluation and health effects evaluation using collected data

Worksheet #3

Worksheet #3: Practical requirements of various study designs

Download the worksheet in Microsoft Word format.