March 5, 2001
The epidemiological team hired by the University of Rhode Island to address the discovery of PCBs in the Chafee Social Science Center met for more than two hours last week with the Chafee Hall Advisory Group.
The three-member team addressed questions from the group, outlined strategies for studying exposure risks and health effects, discussed the types of medical tests that could be involved and reviewed studies on cancer incidence from communities where PCB exposure was high.
J. Vernon Wyman, URI assistant vice president for business services, said he wanted the advisory group to meet with the epidemiological team so they could hear first-hand the expectations of the advisory committee.
The team consists of world-renowned environmental health experts affiliated with the Boston University School of Public Health: Richard W. Clapp, of John Snow Inc.; of Boston, Mass., formerly with the Tufts University School of Medicine; David Michael Ozonoff, professor of public health and chair of the Department of Environmental Health at BU; and Lewis D. Pepper, also with the environmental health department at BU. Pepper is also board certified in occupational and preventive medicine, formerly with Harvard Medical School, and a staff physician at Brigham and Womens Hospital, Boston.
Ozonoff opened the discussion by defining what epidemiology is and the different types of studies that could be initiated, and advantages and disadvantages to each study.
Epidemiology is a branch of public health that deals with the distribution and determinants of disease in populations.
"We (the team members) have been doing this for 30 years and the amount of raw brain power that is in the communities is outstanding," Ozonoff said. "We want to make use of that with this group.
"We also understand that there are individual and group concerns," he said. He said communities and individuals normally ask three types of questions when a toxin or a suspected carcinogen is found their workplaces or communities:
1. "Whats going to happen to us," which is a question related to exposure. Cohort studies are normally engaged to find out the answer to these questions.
2. "Why me?" Why my family," which are outcome driven questions. Case-control studies are normally put in place to answer these questions.
3. "Are we sicker than our neighbors," which would be addressed by cross-sectional studies.
Throughout the meeting, questions came up that touched on all three elements, including a question from a cancer survivor whose office has been in Chafee and a question from another faculty member who asked how her child would be affected, since she was pregnant and nursed her infant while an occupant of Chafee.
Ozonoff outlined and defined the various study options for URI. "This has to be a real team effort, because psychologically we want people to buy into the process, but the real reason is that you know a lot more about this than we do," he said.
The three major study options are:
1. Retrospective cohort studyCompiling a list of everyone who has ever worked in the building and ascertaining vital statistics/cancer diagnoses through such things as the National Death Index and Social Security numbers. This type of research looks back, and requires solid records. Results would then be compared with state and national rates. Study groups would be observed over a period of time to determine the frequency of disease among them.
2. Case controlSelecting a specific disease, such as breast cancer, assembling representative cases from the building during a specific time period, and then comparing that group with a control group, those occupants of the building who have not contracted breast cancer. The groups would be compared on characteristics such as where they worked in the building and their job titles. It is a standard way to develop hypotheses about the causes of a disease, and is one of the least expensive. Ozonoff said by combining the retrospective cohort with the case-control, one would have what is called a nested case-control study. Once the two are combined, the cost becomes higher. Most case-control studies are longitudinal.
3. Cross-sectionalSurveying current occupants of the building. These studies are among the more common types of research designs reported in medical literature and are among the least expensive. These types of studies are often made on total population samples.
Pepper gave a brief description of PCBs and their presence in the environment and discussed the various medical screenings that could be conducted as part of the study (including questionnaires, physical exams and biomedical tests) to determine organ dysfunction or disease in an asymptomatic person or before the person would normally seek medical care.
Biological tests can be done on blood, urine and exhaled air. Pepper said blood tests are as good and less invasive than adipose tests, which examine fatty tissue and are highly invasive. "There is no indication that they (adipose tests) are clinically better," Pepper said.
One individual asked if blood should be given now since faculty and staff have been out of Chafee for 60 days, and he said that is not necessary. He also cautioned that while PCB levels in biological samples are good indicators of exposure, they are not indicative of certain biological outcomes, such as the onset of disease.
Finally, Clapp presented studies that examined the links between PCB exposures and cancer incidence. In eight cohort studies of PCB exposure, there was no evidence of a clear link to breast cancer. "Our data from PCB hot spots dont reach out and grab you by the throat," he said.
Robert Vanderslice, chief of environmental health risk assessment at the Rhode Island Department of Health, who has been attending all of the meetings, said it seemed to him that the following questions summarize the concerns of the advisory group:
1. Were the occupants of Chafee and their children exposed to unusually high levels of PCBs?
4. What are the health risks in comparison to the exposures?
5. Is there a common factor in the breast cancer cases from women who worked in Chafee?
Winifred Brownell, dean of the College of Arts and Sciences, the major tenant in the building, said the other significant question that needs to be answered is, "How will we know that Chafee is safe for reoccupancy?
The group agreed that Vanderslices and Brownells questions are the critical ones.
At its conclusion, the Chafee advisory group members decided to meet to discuss the material presented by the team, so they can make recommendations on the course of the study.