News · Longevity & Aging
PFOA exposure tracked with deaths from brain cancer in a 32,254-person Ohio Valley cohort followed to 2021
People near a chemical plant in the mid-Ohio Valley drank water tainted with PFOA, one of the best-known forever chemicals, for decades. Ten more years of death records added brain cancer to the list of concerns.
- An observational study of 32,254 highly exposed Ohio Valley residents and workers, with 5,709 deaths through 2021.
- PFOA is a forever chemical that leaked into local drinking water from a manufacturing plant for decades.
- Higher estimated lifetime PFOA went with more deaths from brain cancer, and pancreatic cancer in people over 72.
- Bladder cancer showed a weaker, uncertain link; most other causes of death showed no clear pattern.
- With 22 causes of death tested, some links could arise by chance, as the authors caution.
The phrase forever chemicals owes a lot to one community. For decades, people in the mid-Ohio Valley drank water tainted with PFOA (perfluorooctanoic acid) from a nearby plant. A legal settlement in the 2000s paid for one of the largest health studies of its kind. Its results have been cited ever since in debates over how to control these chemicals.
A new analysis in Environment International followed that same group of 32,254 people for another decade, through 2021, this time looking at deaths. Higher lifetime PFOA exposure went with more deaths from brain cancer, and from pancreatic cancer in older participants.
What PFOA and other forever chemicals are
The Environmental Protection Agency describes PFAS (per- and polyfluoroalkyl substances) as widely used, long lasting chemicals, components of which break down very slowly over time. PFOA is one of the most studied members of the family. It lingers in the body for years. So people who drank tainted water kept high levels long after the source was dealt with.
The earlier work on this community set the stage. The authors note that previous studies found probable links with kidney and testicular cancers, raised cholesterol, ulcerative colitis, thyroid disease, and pre-eclampsia, based largely on disease diagnoses through 2011.
How the Ohio Valley mortality study worked
The researchers followed a cohort of 32,254 persons with high PFOA exposure and identified deaths through the national death records. For each person they estimated how much PFOA had built up in the blood over the years, up to 2021. Then they compared death rates between people with more and less lifetime exposure.
Comparing people within the same community, rather than with the general public, avoids some of the differences between regions. The analysis looked at 22 separate causes of death.
Which causes of death tracked with PFOA
By the end of follow-up there were 5709 deaths in the cohort through 2021. Brain cancer stood out: the authors found a positive significant trend between the log cumulative serum level and brain cancer, with risk about 25% higher for each step up in the scale of lifetime exposure.
Two other signals were weaker. Bladder cancer showed a similar direction that was not clearly beyond chance, and pancreatic cancer showed a clear trend only among participants older than 72. The authors note that pancreatic cancer has been associated with PFOA in animal studies, with mixed results in other human studies. Most other causes of death showed no marked pattern, except for stroke among the plant’s workers.
Why a brain cancer signal matters
Brain cancer had not been on the list of conditions linked to PFOA in the earlier work on this community, so a new signal after ten more years is notable. Cancers can take decades to develop, and a mortality study can pick up effects that earlier, shorter follow-up missed.
At the same time, the authors are careful about what it means. Brain cancer is uncommon, so the number of deaths behind the estimate is modest, and a single study is not enough to add it firmly to the list.
What a single-cohort PFOA study cannot show
The authors flag the main statistical caution themselves: caution is warranted due to multiple comparisons. Testing 22 causes of death makes it likely that one or two will look linked by chance, and the brain cancer finding needs to be confirmed in other groups.
Exposure was estimated from models of water supply and blood tests, not measured throughout each person’s life, and people in this community were exposed to far more PFOA than most of the public. That makes the findings important for heavily exposed communities but harder to translate to the low levels most people carry.
What this changes for thinking about forever chemicals
For most people, the direct lesson is limited: exposure in the Ohio Valley was unusually high. But PFAS are found in drinking water in many places, and the long reach of this community’s findings is a reason regulators have moved to lower permitted levels.
For anyone concerned about their own water, the practical steps are checking the local water quality report and, if PFAS are present, using a filter certified to reduce them. For researchers, the brain cancer signal is a clear target for confirmation in other exposed populations.
People also ask
What did the study find?
There were 5,709 deaths through 2021. Higher cumulative PFOA was significantly associated with brain cancer mortality (HR 1.25 per log unit), with a suggestive but non-significant association with bladder cancer (HR 1.17), meaning it could be chance. Pancreatic cancer showed a positive trend among participants older than 72 (HR 1.23). No other causes showed marked positive trends, except stroke among workers.
What is PFOA?
Perfluorooctanoic acid, one of the PFAS family of chemicals once used to make nonstick and water-resistant products. It breaks down extremely slowly, which is why PFAS are called forever chemicals.
Who was in the cohort?
People living near a chemical plant in the mid-Ohio Valley whose drinking water was contaminated with PFOA, plus plant workers. They were enrolled in the 2000s for a legal settlement that funded health studies.
What had earlier studies of this group found?
A panel of scientists previously found probable links between PFOA and kidney and testicular cancers, high cholesterol, ulcerative colitis, thyroid disease and pre-eclampsia.
Should I worry about PFAS in my water?
Exposure in this community was far higher than typical. Many water utilities now test for PFAS; your local water report will say what is in yours, and filters certified to reduce PFAS are available. This is general information rather than medical advice.
Why the caution about multiple comparisons?
When researchers test many causes of death at once, a few will look linked by chance alone. That is why single findings like the brain cancer link need confirming elsewhere.