Oak Ridge Reservation: Public Health Assessment Work Group
Public Health Assessment Work Group
August 5, 2002 - Meeting Minutes
ORRHES Members attending:
Bob Craig (Work Group Chair), Kowetha Davidson (Subgroup Chair), David Johnson, Susan Kaplan, James Lewis, and LC Manley
Public Members attending:
Peggy Adkins, Gordon Blaylock, Al Brooks, Beth Freeman, and Timothy Joseph
ATSDR Staff attending:
LaFreta Dalton, Jack Hanley, Bill Murray, and Melissa Fish (intern)
Bob Craig called the PHAWG meeting to order and attendance was noted for the record.
The purpose of this meeting was to (1) discuss combining I-131 doses from the Nevada Test Site (NTS) and Oak Ridge Reservation (ORR) and (2) discuss and vote on whether two draft recommendations should be submitted to ORRHES.
Issue 1. Combining I-131 Doses from NTS and ORR
Why county-specific estimates should not be used for individual estimates of I-131 doses from NTS
Kowetha Davidson presented a response to Why county-specific estimates should not be used for individual estimates of I-131 doses from NTS. She provided the following information:
“The following information is taken from the National Academy of Science’s Institute of Medicine (NAS/IOM) review (Exposure of the American People to Iodine-131 from Nevada Nuclear-Bomb Tests) of the National Cancer Institutes’s (NCI) study on I-131 exposure from the Nevada Test Site (Estimated Exposures and Thyroid Doses Received by the American People from Iodine-131 in Fallout Following Nevada Atmospheric Nuclear Bomb Tests).
The NAS/IOM stated in its Executive Summary ‘3. The levels of detail presented in the report, specifically, county-specific estimates of iodine-131 thyroid doses, are probably too uncertain to by used in estimating individual exposure...Estimates of county-specific exposure may also have little relevance to specific individuals for whom exposure depends on such critical factors as varying individual consumption of milk and other foods and variations in the source of those foods.’ ‘4. Individual-specific estimates of past exposure to iodine-131 from the Nevada tests are possible but uncertain often highly so, because critical data are often not available or of questionable reliability.’
‘Determination of the doses to members of the public is subject to the highly variable behavior of individuals and the uncertainties in the calculated pathways levels. For these reasons, the NCI report presents doses as averages for representative groups’...‘Only limited information is given in the report on the variability of individual dose estimates around the group or county averages. It is clear, however, that individual dose estimates must be more uncertain than are county averages.’...‘individual doses will vary considerably about the county averages, especially in children. There are two independent components to this variability. First, there will be variation in average doses within counties because of different exposure conditions at different locations and because of differences in the size of the counties and the size and intensity of a storm causing deposition. Second, there will be variation between individuals with the same exposure conditions because of differences in consumption.’
...‘The combined effect of the two sources of variation will set large uncertainties on individual doses even where reliable estimates of contamination at the county level are available.’”
Discussion of individual vs population risk
Kowetha Davidson noted that there are two types of risk—individual risk and excess lifetime risk in a population. She remarked that statistics can provide information in certain situations. When looking at the data from a toxicologic point of view, one has to consider that if the data are so highly variable that the margin of error is so large the answer becomes meaningless (as is the case with determining individual risk). She said that if the answer is meaningless, why calculate the numbers in the first place? In response to James Lewis’s question about the consensus, Kowetha Davidson recommended estimating population risks only.
Al Brooks said that this could be pointed out for any statistical study (i.e., that there is more uncertainty in individual estimates than in an average of the estimate; therefore, we should not estimate individual doses). He disagreed with this statement and concluded that individual exposure should be estimated and a wide margin of error be applied. If the uncertainty is so large, then note that the evaluation is not reliable. He warned that if a proper estimate of uncertainty of individual exposure is not provided, people will arrive at their own (incorrect) conclusions.
Susan Kaplan explained that if the numbers are not calculated and discussed, then no one will understand the rationale for not calculating the numbers in the first place.
Jack Hanley explained that risk factors (such as the geographic area where you were born, where you lived as a child, how old you were at the time of exposure, and if you drank backyard cows milk) will be explained, so that a person can conclude whether they should consult a physician. ATSDR can provide physician education programs to help the doctors assess individual exposure situations. His opinion is that the health assessment should focus on the population and an individual’s situation should be handled by a doctor in a clinic.
Discussion of combining doses from NTS and ORR
In response to LC Manley’s question, Timothy Joseph explained that doses will be looked at separately in addition to being combined for the purposes of providing a complete picture. Gordon Blaylock noted that if NTS is not included, there could be a potential credibility concern. James Lewis wanted to know if they were setting a precedent to combine doses for all the chemicals. Susan Kaplan, however, responded that the decision to combine doses will be determined individually for each chemical. At LC Manley and Davison’s remarks, the group discussed whether this issue goes beyond their mandate.
James Lewis asked if the NAS recommended or tried to combine doses. Kowetha Davidson replied that there was not an issue of combining doses at NTS. Jack Hanley responded that they did not add the doses at Hanford, but are studying additional options.
Bob Craig summarized that the NTS data has tremendous variability, more so than the data for ORR. When there is a lot of uncertainty involved it does not provide a clear picture for members of the public. However, for the purposes of full disclosure, he noted that it seems the general consensus is to use the NTS data, but provide a clear discussion of the uncertainty involved.
Why ATSDR should focus on dose estimates rather than risk estimates
Kowetha Davidson presented a response to Why ATSDR should focus on dose estimates rather than risk estimates. She provided the following information:
“Do the risk estimates include benign and malignant thyroid lesions? If benign lesions are included, then the risk estimates are overestimated. Applying the linear threshold model should preclude consideration of benign lesions, because benign lesions are consistent with a nonlinear mode of action and a threshold model.
Individual risk estimates are associated with probability of causation, which is a legal issue tied in with monetary compensation. It is not within the mandate of ORRHES to become involved in legal issues. The primary focus of ORRHES is the public health.
Individual-specific estimates of the probability of developing thyroid cancer from exposure to fallout from the Nevada testing program are uncertain to a greater degree than the dose estimates because of the additional uncertainty, in particular, about the cancer-causing effect of low-doses of I-131.
Estimates of lifetime excess cases of thyroid cancer are more appropriate from a public health perspective. A public health response can be developed around dose and estimates of excess cases of cancer.”
Kowetha Davidson explained that a linear threshold model is used for thyroid cancers. However, her concern is that if benign lesions are included in the risk estimates, then the risks are overestimated. Benign lesions follow a nonlinear mode of action because there is a precursor to the lesions, hyperplasia, which has a threshold effect. She also noted a second concern—the role of endocrine disruption within the thyroid. She explained that if the feedback mechanisms for the thyroid hormone are disrupted, the level of thyroid stimulating hormone (TSH) can be controlled. If you have a situation in which thyroid hormone levels are constantly low then your TSH level will be constantly high, which overstimulates the thyroid and causes cell proliferation. If you control the feedback mechanism then you can control the proliferation that is induced by the TSH. This control mechanism can be set up in the thyroid or in the liver. If you have increased metabolism of thyroid hormones in the liver your thyroid hormone levels can be lowered, which will increase TSH production and cause the cells to keep reproducing within the thyroid. Therefore, there are two different modes of action and using only one model to account for those modes of action overestimates the risk.
Clarification on the medical aspect of hyperthyroidism, endocrine disruption, and hyperplasia
In response to Peggy Adkins’ question, Kowetha Davidson clarified that I-131 would not be expected to affect the metabolism of hormones within the liver. However, if a person was exposed to high enough doses of I-131, hormone producing cells within the thyroid could be destroyed and could result in a disruption of the production of thyroid hormones, which can cause endocrine disruption.
In response to Gordon Blaylock’s question about the difference between hyperthyroidism, hypothyroidism, benign tumors, and thyroid tumors; Kowetha Davidson explained that in most situations where a large number of benign tumors (preceded by hyperplasia) precede carcinomas, you are seeing a response to injury and will have a threshold model.
In response to Susan Kaplan’s question, Kowetha Davidson defined hyperplasia as a controlled proliferation of cells (i.e., not in an uncontrolled manner, like with cancer). For example, hyperplasia can be a response to injury to replace cells that were destroyed.
Gordon Blaylock noted that increasing the number of cells is due to not enough thyroxin, like in the case of the Goiter Belts. In response to Bill Murray’s request, Gordon Blaylock explained that Goiter Belts are areas where there was a lack of iodine in the diet.
Peggy Adkins noted that there are various thyroid disorders in the community. She thinks the public would want to know any affects I-131 has on any other symptoms, not just malignant tumors, since any damage to the thyroid has the potential to affect other body parts.
Kowetha Davidson mentioned that there are other contaminants in the environment that are endocrine disruptors, such as pesticides. Also, low iodine diets in children are believed to exacerbate the effects of I-131 on the thyroid, causing high cases of malignant thyroid cancer in children.
Discussion of whether the risk estimates should include benign and malignant tumors
James Lewis asked if we know whether the risk estimates include benign and malignant tumors. Gordon Blaylock responded that at the moment we do not know, but we can definitely find out.
Discussion of dose estimates vs risk estimates
Jack Hanley explained that the Institute of Medicine, supported by NAS, did not feel confident enough in the data to convert dose estimates into risk estimates. He reiterated that they could not quantify the risk. NAS suggested that the Department of Health and Human Services (DHHS) consider additional analyses to evaluate estimates of confidence intervals for risk projection and to improve understanding of sensitivity and projections to changes and key assumptions. Based on that suggestion, NCI urged caution in interpreting the results, particularly because the study does not directly address the question of cancer risks from fallout. NCI and DHHS have enlisted the help of the foremost radiation experts in the country to fully evaluate risk and develop an appropriate public health response.
Al Brooks remarked that if NCI could not calculate risk estimates from dose estimates, then unless there is new data, ORRHES should not presume to be able to calculate risk. James Lewis agreed that if there already is a multi-million dollar, credible agency with the best minds investigating how to calculate doses for I-131 into risks, ORRHES should not duplicate efforts and potentially “go down another path.”
In response to Al Brooks’ question, Jack Hanley explained that dose estimates can be used to determine if there is a health concern. For example, the doses at Oak Ridge can be compared to doses from epidemiologic studies that have evaluated health effects from exposure to I-131 at other sites.
Gordon Blaylock said that there have been recent meetings where people have recommended calculating risks. Jack Hanley clarified that individuals have been discussing estimating risks, however, the committees have not come to a conclusion and have not published their recommendations yet. James Lewis recommended that someone determine the status as an action item. Jack Hanley recommended Paul Charp follow-up because he is already looking into the NAS and Chernobyl studies.
James Lewis researched “perception of risk” and found an interesting abstract that said that women perceive their risk of breast, colon, or cervical cancer in terms of risk factors such as, heredity, environment, and lifestyle choices. Women do not perceive risk in terms of numbers. Al Brooks said that the comments are not applicable to risks when they are small. He commented that perception is how the person views a situation, but the outcome is dependent upon the numbers. Kowetha Davidson responded that no matter what the risk number is, if a person fits into the risk categories they should be concerned.
Susan Kaplan said that she is afraid that if only doses are presented in the health assessment, everyone will feel like they need to go to their doctors to assess their risk. Kowetha Davidson and Jack Hanley remarked that doses and risk factors will definitely be part of the PHA. Jack Hanley suggested showing the geographic area, time frame, and risk factors of concern; then explaining if a person falls into those risk factors, they should be evaluated by their physician. The group responded that was a reasonable approach.
Issue 2. Discussion of Draft Recommendations
Kowetha Davidson motioned that PHAWG recommends that:
“ORRHES recommends that CDC/ATSDR present the public health implications of I-131 doses due to releases from the Oak Ridge Department of Energy Reservation, the Nevada Test Site (NTS), and the combined doses from the Oak Ridge Reservation and NTS in it Public Health Assessment for I-131. ATSDR should present the doses, their ranges of uncertainty, and an explanation of the level of uncertainty for public understanding.”
Al Brooks seconded the motion.
Susan Kaplan motioned to add “and risks” to the recommendation anywhere dose is mentioned. David Johnson seconded the motion.
Discussion of the amendment to the first recommendation
Jack Hanley reminded the group that NCI and NAS cautioned the use of interpreting the results of cancer risks. Timothy Joseph suggested adding a caveat “when feasible” so that ORRHES is not asking ATSDR to do something that is impossible. Jack Hanley asked who will determine if it is feasible to conduct risks. The group responded that ATSDR will determine if it is feasible. Jack Hanley suggested adding “if ATSDR determines it is feasible to determine risks.”
Timothy Joseph explained that ORRHES is asking ATSDR to consider doing risk estimates. Susan Kaplan said ATSDR can estimate some rough risk estimates, regardless of what NCI and NAS conclude.
Voting on the amendment to the first recommendation (adding the words “and risks, if feasible”):
The following eight people voted in favor of the amendment: Peggy Adkins,
Gordon Blaylock, Al Brooks, Bob Craig, Beth Freeman, David Johnson, Timothy
Joseph, and Susan Kaplan.
The following two people voted against the amendment: James Lewis and LC Manley.
The amendment passed.
Voting on the first recommendation, as amended:
“ORRHES recommends that CDC/ATSDR present the public health implications of I-131 thyroid doses (and risks, if feasible) due to releases from the Department of Energy’s (DOE) Oak Ridge Reservation (ORR), the Nevada Test Site (NTS), and the combined doses (and risks, if feasible) from the ORR and NTS in its Public Health Assessment for I-131. ATSDR should present the doses (and risks, if feasible), their ranges of uncertainty, and an explanation of the level of uncertainty for public understanding.”
The following eight people voted in favor of the recommendation: Peggy Adkins, Gordon Blaylock, Al Brooks, Bob Craig, Beth Freeman, David Johnson, Timothy Joseph, and Susan Kaplan.
The following two people voted against the recommendation: James Lewis and LC Manley.
The recommendation passed.
Kowetha Davidson motioned that PHAWG recommends that:
“ORRHES recommends that CDC/ATSDR establish an online dose calculator so that individuals may obtain estimates of their thyroid doses due to releases of I-131 from the Oak Ridge Department of Energy Reservation and from the Nevada Test Site along with an option for adding the doses. CDC/ATSDR should provide information to the public on interpretation of the results from the dose calculator and any follow-up action the individual should take as a result of the estimate.”
Al Brooks seconded the motion.
Al Brooks motioned to add “and risks, if feasible” to the recommendation anywhere dose is mentioned. Gordon Blaylock seconded the motion.
Voting on the first amendment to the second recommendation (adding words “and risks, if feasible”):
The following eight people voted in favor of the amendment: Peggy Adkins, Gordon Blaylock, Al Brooks, Bob Craig, Beth Freeman, David Johnson, Susan Kaplan, and James Lewis.
The following two people voted against the amendment: Timothy Joseph and LC Manley.
The first amendment passed.
Discussion of the second recommendation
Jack Hanley noted that Charlie Miller told him that they had a dose calculator on the Internet for people at Hanford, however, they have removed it for lack of interest and use. Gordon Blaylock said that SENES (at www.senes.com) has a dose/risk calculator, but is unsure of the usage. Al Brooks commented that even if the use of an online calculator is limited, it is still necessary to provide it to prevent any credibility issues.
Peggy Adkins commented that there should be an option for adding doses, as well as being able to calculate individual estimates. Kowetha Davidson agreed that it would be beneficial in case it becomes possible in the future. Al Brooks believes that the option for adding doses should be user-friendly and apparent. Timothy Joseph’s assumption is that the choice will be made clear when using the calculator.
Timothy Joseph is concerned that there is no language in the recommendation that says ATSDR should explain the accuracy, range of variability, or data input of the calculator and the credibility of the answer. He recommends that the limitations of the calculator be made clear to the public.
Timothy Joseph motioned to add “uncertainty, and credibility” after “CDC/ATSDR should provide information to the public on interpretation...” Susan Kaplan seconded the motion.
Discussion of the second amendment:
James Lewis wanted to know if there was any liability associated with the dose calculator. The group did not think so.
Voting on the second amendment to the second recommendation (adding the words “uncertainty, and credibility”):
The following eight people voted in favor of the amendment: Peggy Adkins, Gordon Blaylock, Al Brooks, Bob Craig, Beth Freeman, Timothy Joseph, Susan Kaplan, and James Lewis.
The following two people voted against the amendment: David Johnson and LC Manley.
The second amendment passed.
Voting on the second recommendation, as amended:
“ORRHES recommends that CDC/ATSDR establish an online calculator so that individuals may obtain estimates of their thyroid doses (and risks, if feasible) due to releases of I-131 from the Oak Ridge Department of Energy Reservation and from the Nevada Test Site along with an option for adding the doses (and risks, if feasible). CDC/ATSDR should provide information to the public on interpretation, uncertainty, and credibility of the results from the calculator and any follow-up action the individual should take as a result of the estimate.”
The following nine people voted in favor of the recommendation: Peggy Adkins, Gordon Blaylock, Al Brooks, Bob Craig, Beth Freeman, David Johnson, Timothy Joseph, James Lewis, and Susan Kaplan.
The following person abstained from voting: LC Manley.
The second recommendation passed.
Issue 3. New Business
Peggy Adkins motioned that PHAWG recommends that:
“ORRHES recommends that individuals be provided an interactive Web site for estimating individual risks of negative health effects from I-131 based on symptomatic, geographic, historic factors and other personal pertinent data.”
Susan Kaplan seconded the motion.
Peggy Adkins wants the document to be a helpful resource for people with health effects. She would like people who are sick with strange symptoms to be able to describe what risk factors and symptoms they have, receive answers to their health concerns, and direction to where they can receive help. Peggy Adkins suggests that an interactive Web site will allow people who have bizarre symptoms to learn additional information.
Susan Kaplan clarified that the calculator can be used in situations where a person already knows he/she was exposed to I-131. She said that Peggy Adkins is suggesting a resource for people to use if they have X, Y, and Z symptoms and they do not know that they were exposed to I-131. The resource can tell them that they may have been exposed to I-131 and that they should go see a doctor.
Discussion of the third recommendation
The group discussed whether the components of the recommendation were already going to be included in the public health assessment process, such as with physician and public health education. They also discussed whether it is possible to conduct an extensive medical survey of the literature which would be needed to create this kind of interactive Web site.
Susan Kaplan mentioned that a 1995 DHHS/NIOSH Report to Congress on Worker’s Home Contamination looked at various occupations and what contaminants people can be exposed to. Her brief review of the study lead her to believe that it is possible to provide the information, but she noted that it would require a lot of work. She suggested PHAWG look at the report.
Timothy Joseph asked Peggy Adkins if she wanted a fairly extensive Web site discussion about thyroid cancer and thyroid problems that talks about symptoms for the purpose of knowledge or self-diagnosis. Susan Kaplan noted that people should not be trying to diagnose themselves; the physicians should be educated on diagnosing people. Timothy Joseph suggested she might be looking for a combination of the calculator and a thorough discussion of symptoms.
Peggy Adkins said the main point of public interest will be missed if symptoms are not considered. Susan Kaplan mentioned that there are many medical books with symptom-based flowcharts that can perhaps provide a basis for what Peggy Adkins is requesting. James Lewis and Al Brooks noted that providing vague symptoms can be misleading.
Kowetha Davidson suggested that ATSDR provide fact sheets (for physicians and the public) that discuss health effects of contaminants. She said that the fact sheets can provide the necessary information in a way that will not also imply self-diagnosis. Al Brooks suggested electronically providing fact sheets on the ORRHES Web site. Kowetha Davidson also noted that ATSDR has toxicological profiles that discuss health effects associated with contaminants and suggested creating a link from the ORRHES Web site to the toxicological profiles. Jack Hanley mentioned that each toxicological profile has a Public Health Statement that was written for the lay person.
David Johnson mentioned that the process should be simple and easy for people to access. He also noted that financial ability should not be overlooked. He commented that there are many resources that can be utilized outside of ATSDR, such as county health departments, the Lupus Foundation, the Diabetes Foundation, and the Cancer Foundation.
Jack Hanley read from a fact sheet—Questions and Answers on the NCI Fallout Report—“Question: What should people do who are concerned about cancer risk from fallout exposure? Answer: Anyone who is concerned about cancer risk from fallout should request a thyroid examination as part of their next visit to their physician.” Bottom-line is that if you have a concern and you meet some general criteria of risk factors you should see a physician and have your thyroid checked out.
James Lewis mentioned that the Web site should provide a list of recommended specialists for people who have environmental and occupational health concerns to consult.
Voting on the third recommendation:
The following two people voted in favor of the recommendation: Peggy Adkins and David Johnson.
The following five people voted against the recommendation: Gordon Blaylock, Al Brooks, Bob Craig, LC Manley, and James Lewis.
The following two people abstained from voting: Beth Freeman and Susan Kaplan.
The recommendation fails. However, Bob Craig noted that PHAWG will take the contents of the web site under advisement.