There is an art to science, and science in art;
the two are not enemies, but different aspects of the whole.
Isaac Asimov, 1988
Breast Cancer and MCS in EHP
In recent years, much progress has been made in understanding why certain women develop breast cancer, and several studies have proposed that environmental factors can significantly affect a person's likelihood of the disease. Despite these advances, the mechanisms underlying cancer largely remain a mystery. Similarly, many researchers have suggested that the recently diagnosed phenomenon known as multiple chemical sensitivity (MCS) could be caused by exposure to environmental toxins, but how these chemicals enter the body and cause such a reaction remains a mystery.
EHP
will publish two monographs containing important research on these subjects,
Experimental Approaches to Chemical Sensitivity
in March 1997 and
Hormones, Hormone Metabolism, and Breast Cancer
in April 1997.
MCS is a poorly understood condition in which patients have severe reactions to chemicals in concentrations that most people can easily tolerate. Perfumes, household cleaners, and petroleum-based products have been reported to cause illness in some patients suffering from MCS. Chemicals, however, do not always trigger the same responses among different MCS patients and, although some patients have reported past exposure to a known toxicant that coincided with the onset of MCS, others can report no such exposure, making the condition difficult to characterize and diagnose.
Clinical ecologists have long suggested that exposure to low levels of chemicals can cause physiological responses in genetically susceptible persons including illnesses such as cancer and arthritis. On the other hand, in an attempt to distinguish the condition from known occupational diseases and psychiatric conditions, the occupational health literature has provided a definition of MCS as a novel condition that could possibly be acquired through classic conditioning. Each approach carries different implications for how MCS should be studied and what kind of treatments are likely to be effective.
The mystery of MCS.
Characterizing multiple chemical sensitivity is made difficult by the broad range of symptoms associated with it.
Source: Miller CS. Toxicant-induced loss of tolerance--an emerging theory of disease? Environ Health Perspect 105(suppl 2):445-453 (1997)
"If this is a purely psychological phenomenon--that is, one that is conditioned--then it can be learned or unlearned," says Nancy Fiedler, associate professor in the Environmental and Occupational Health Sciences Institute of the Robert Woods Johnson Medical School, who led the MCS workshop that prompted the MCS monograph. "On the other hand, others would suggest that we need to extend the dose-response curves to include physiological responses that can be brought on by very low doses. These are responses that cannot be unlearned . . . through psychiatric therapy."
Other researchers disagree with the notion that MCS can be effectively studied as either a purely psychological or purely physiological phenomenon. Some have suggested that stress must accompany a toxic exposure to initiate sensitivity. Others propose that an initiating exposure can affect the physiology of the brain through a process similar to the limbic kindling seen in animals, through which intermittent low-level stimuli can cause the brain to change so that further stimulus will initiate full-blown seizures. According to Iris Bell, director of the Geriatric Psychiatry program at the Tucson Veterans Affairs Medical Center, "The mind versus body conceptualization of MCS is extremely erroneous." Bell says that a better understanding of the field of psychology would allow researchers to better understand MCS as a complex mind-body interaction.
Experimental Approaches to Chemical Sensitivity
attempts to provide a basis for comparing the different approaches toward MCS in hopes of developing a unified research strategy. Some papers in the monograph deal with clinical case studies that describe various symptoms and characteristics of MCS patients. Other papers propose models for MCS, describing the condition as related to the learning process, to time-dependent sensitization, or to the mechanisms underlying drug abuse. Still others suggest experimental methods and variables that could be employed in experimental studies of MCS.
Hormones, Hormone Metabolism, and Breast Cancer
is dedicated to the issues of breast cancer and the effects of hormones on the development of this disease, the most common cancer among women. An October 1993 petition signed by 2.6 million people asked President Clinton for a new strategy to fight breast cancer. This petition led to the development of the National Action Plan on Breast Cancer (NAPBC). The Etiology Working Group of the NAPBC, together with the National Cancer Institute, Tulane University's Center for Bioenvironmental Research, and the U.S. Public Health Service's Office of Women's Health convened a workshop on hormones and breast cancer 28-29 September 1995. Selected papers from this workshop, as well as some response papers, form the basis of
Hormones, Hormone Metabolism, and Breast Cancer
.
Hormones and breast cancer.
Steroid hormone metabolites having estrogenic or antiestrogenic properties exert their growth modulatory effects indirectly via receptor-mediated mechanisms, leading to aberrant proliferation and breast cancer.
Source: Davis DL, Nitin TT, Osborne MP, Bradlow HL. Medical hypothesis: bi-functional genetic/hormonal pathways to breast cancer. Environ Health Perspect 105(suppl 3): in press (1997)
Modern epidemiological studies have found that most of the known risk factors for breast cancer, excluding radiation, are directly related to lifetime exposure to estradiol and other hormones. Researchers have reasoned that any environmental chemical that has the ability to mimic human hormones or affect their metabolism may be carcinogenic. However, some xenohormones (such as DDT) appear to be harmful, while others (such as phytoestrogens) appear to be protective. The mechanisms by which xenohormones influence bodily processes, potentially leading to cancer, have not been decisively identified. The papers presented in
Hormones, Hormone Metabolism, and Breast Cancer
contribute to elucidating these mechanisms and differentiating among helpful and harmful hormones.
The monograph also includes views and concerns of some breast cancer research advocates. For example, Sandra Steingraber of the Women's Community Cancer Project writes about her concern that more work is being done to identify the mechanisms of cancer than is being done to protect the public from the disease. "We are interested in research that identifies breast carcinogens, and we [are also] interested in social changes that would keep these agents out of women's breasts in the first place," says Steingraber. In another paper, Craig Dees of the Oak Ridge National Laboratory and colleagues propose that the colorant Red Number 3 causes genetic damage and could be a significant risk factor for breast cancer.
Other researchers present additional support for a link between sex hormone levels and breast cancer incidence. One nested case-control study by Joanne F. Dorgan of the National Cancer Institute and colleagues examines serum estrogen levels and cancer incidence in postmenopausal women. Another paper finds that dietary estrogens at low concentrations can stimulate human breast cells to begin replication. In a paper by Ruth H. Allen of the National Cancer Institute and colleagues, the relationship between increasing breast cancer incidence among women in Hawaii and the use of pesticides there provides evidence of a link between xenohormones and cancer risk.
Research on the link between known risk factors for breast cancer and lifetime exposure to bioavailable estradiol has led to the idea that xenohormones can affect the body by two distinct paths, either by attacking DNA directly or by interacting with endogenous hormones and altering the formation of hormone metabolites. A paper by Takeki Tsutsui of the Nippon Dental University and colleagues found evidence of DNA adduct formation and aneuploidy induction (precursors to cancer) in response to estrogen. The mechanism by which phytoestrogens may work to prevent cancers is discussd in
Hormones, Hormone Metabolism, and Breast Cancer,
and
monograph authors suggest that these chemicals act to reduce the binding of other xenoestrogens to human estrogen receptors. It is also suggested in the monograph that the presence or absence of lipophilic regions on estrogens and xenoestrogens may affect their binding characteristics and could be used to distinguish harmful estrogens from beneficial ones.
The papers presented in
Hormones, Hormone Metabolism, and Breast Cancer
also discuss ways of measuring human hormone levels as a means of assessing an individual's risk of developing breast cancer. Researchers compared the sensitivity of two competing methods of measuring hormone metabolites (2-hydroxyestrone and 16
-hydroxyestrone immunoassays) and found a high degree of agreement for premenopausal women, a finding that could lead to more refined methods of measurement. Other authors identified ways to measure xenoestrogen levels in human serum. According to Devra Davis, program director of the Health, Environment, and Development Program of the World Resources Institute and an editor of the monograph, better methods of measuring hormone levels will make it easier for scientists to identify environmental carcinogens. "Experimental methods for identifying hazards need to be developed, and measuring [xenohormone] levels present [in the body] is a very direct way of assessing exposure." Davis said that future research should concentrate on these issues.
New Dimensions to Dementia
Two studies published last September provide new clues to possible links between environmental factors and neurodegenerative diseases. Both genetic and environmental factors are thought to play a role in the development of such diseases. However, until now, "more progress has been made on the genetic side of the equation," says George Martin, director of the Alzheimer's Disease Research Center at the University of Washington in Seattle. These studies and others like them are the latest attempts to rectify that imbalance.
The first study, published in the 25 September 1996 issue of the
Journal of the American Medical Association
(JAMA)
, estimated the prevalence of two major types of dementia--Alzheimer's disease and vascular, or stroke-related, dementia--in about 3,700 Japanese-American men over age 70. These men are surviving members of the Honolulu Heart Program, a longitudinal study that began in 1965 to investigate cross-cultural differences in heart disease. All of the subjects lived in Hawaii at the study's outset.
Based on past reports, Alzheimer's disease is the predominant type of dementia in Western nations, while vascular dementia is predominant in Japan. "In our study, the men had almost as much vascular dementia as is found in Japanese men living in Japan," says Helen Petrovitch, an associate professor of medicine at the University of Hawaii and coauthor of the study. "However, they also had Alzheimer's disease at a rate almost equal to what is seen in the United States. It appears that something about moving from Japan led to an increase in Alzheimer's disease prevalence."
Martin calls the paper a landmark study and says that these data are the best yet available on whether the introduction of a new environment can make a difference in the occurrence of Alzheimer's disease. "The question for the future," says Martin, "is what factor in the environment is leading to more Alzheimer's. It is an extraordinarily important question, because if you can identify some contributing factor in the environment, then you may be able to use this knowledge to postpone the disease."
The
JAMA
study has been criticized for relying on comparisons among prevalence studies that used slightly different diagnostic criteria. The diagnosis of Alzheimer's disease is notoriously tricky. A definite diagnosis can only be made after death by autopsy of the brain. The clinical diagnosis of Alzheimer's disease in living patients is much more subjective. "When we make comparisons among surveys conducted by various researchers, part of the reason we find prevalence differences may be that the disease was just defined differently," says Petrovitch. This problem is now being addressed in ongoing research. "We have sister centers in Japan, Seattle, and Taiwan, and we're standardizing our diagnostic criteria and methods at all these sites," Petrovitch says. The results are expected to be available within a year. When they are, scientists should have a better base for comparing Alzheimer's disease across cultures.
A second study on a related topic appeared in the September 1996 issue of the
American Journal of Public Health
. Researchers in this study examined the occurrence of four neurodegenerative diseases--Alzheimer's disease, presenile dementia, Parkinson's disease, and motor neuron disease--among members of various occupations. Lead author Paul Schulte, an epidemiologist at the National Institute for Occupational Safety and Health, and his colleagues examined death certificates from 27 states for the period 1982-1991. They looked for death certificates where one of the diseases was mentioned as either the main cause or a contributing cause of death. They also noted the occupations listed on those certificates.
The researchers then compared the actual proportion of deaths from a specific disease within a particular occupational group to the expected proportion--the proportion of deaths from that disease in all occupations. In a number of cases, the actual proportion exceeded the expected proportion by a statistically significant amount. More deaths than expected from all four diseases were found for teachers, medical personnel, machinists and machine operators, scientists, writers, designers, entertainers, and support and clerical workers. Excessive death rates from some diseases were also found for people with jobs involving pesticides, solvents, and electromagnetic fields. The bottom line, says Schulte, is that "these neurodegenerative diseases don't appear to be occurring randomly, but occur more frequently in some occupations than in others."
"This is just a preliminary investigation," cautions Schulte. In fact, there are serious limitations to the study. For one thing, death certificates provide only a rough measure of disease occurrence and usual occupation, and no information at all about other occupations and risk factors. Also, this type of study design is not able to clarify cause-and-effect relationships. The value of studies such as this one, Schulte says, "is [in] generating leads for future research."
"This kind of study is the very first step in a series of epidemiologic inquiries," says Gwen Collman, an environmental epidemiologist at the NIEHS. The
JAMA
study, with its more sophisticated design, is a few steps farther along the trail. However, both studies are still some distance from showing which environmental factors are critical to the development of neurodegenerative diseases so that such information may be used to postpone or prevent these illnesses.
The Arctic Council
"The Arctic is an early warning system for our planet," said Sergio Marchi, Canadian minister of the environment, speaking at the 19 September 1996 inauguration of the Arctic council. The council is an intergovernmental forum designed to build consensus on issues of environment and sustainable development, as well as monitor pollution, disseminate information, and promote cooperation among the eight Arctic nations and their indigenous populations.
The Arctic Council evolved from the Arctic Environmental Protection Strategy (AEPS), established in 1991 to deal with the threat of polar pollution. In the summer of 1997, the Arctic Council will take over the work of the AEPS. Specifically, four committees of the AEPS will continue to work through the Arctic Council. The Arctic Monitoring and Assessment Program Committee will assess the impact on health of contaminants including radionuclides, persistent organic toxics, and toxic metals. The Conservation of Arctic Flora and Fauna Committee will compile lists of endangered species and environmentally protected areas. The Protection of the Arctic Marine Environment Committee will survey land-based sources of pollution and establish guidelines for environmentally sound development including that of offshore oil drilling. Finally, the Emergency Prevention, Preparedness, and Response Committee will assess emergency notification systems and compile a risk matrix that identifies environmental risk factors and their significance.
According to Robert Senseney, polar affairs chief for the U.S. State Department, the Arctic Council is negotiating rules of procedure and guidelines for emergency preparedness and sustainable development. "Emphasis is on a proactive approach and involves consultation with industry, governments, and environmental groups," says Senseney. Voting members of the council are high-level government representatives from Canada, Denmark (voting also for Greenland), Finland, Iceland, Norway, the Russian Federation, Sweden, and the United States. There are also nonvoting permanent participants including the Inuit Circumpolar Conference; the Saami Council (Laplanders); and the Association of the Indigenous Minorities of the North, Siberia, and the Far East of the Russian Federation. The Arctic Council will not produce legally binding treaties or deal with military security.
Sierra Club Chairman Mike McCloskey says that danger signals such as problems in polar bear reproduction and evidence of tropical pesticides in Arctic ice have prompted requests for more research on pollution levels and transport in the Arctic. Environmental issues arising from events such as the opening of the Northwest Passage to maritime shipping and the development of renewable resources, says Mary Simon, Canadian ambassador for circumpolar affairs, have also contributed to the need for more funding of Arctic research. The council is also committed to improving the economic conditions, health, and cultural well-being of indigenous people, so it will work to develop policies on issues such as contamination of the food chain, maintaining animal populations, and sustaining indigenous lifestyles that depend on fishing and hunting.
Painting a Healthier Picture
The health hazards associated with art may seem like an issue that affects only a few members of society--individuals who devote their lives to spending long hours in often small, poorly ventilated studios, often working with toxic materials, to create paintings and sculptures. Though the risk of exposure to toxic art materials may be greatest for professional artists, the many people who draw, paint, process photographs, or work with ceramics as a hobby can also be exposed to toxic chemicals and harmful dusts. In addition, many secondary schools offer art classes that use these same materials, and warnings such as the one issued by the U.S. Consumer Product Safety Commission in 1994 concerning lead in crayons serve as reminders that even children can be at risk.
Since 1977, the Center for Safety in the Arts (CSA) has supported research and disseminated information on the health hazards associated with both the visual and performing arts. Due to cuts in federal and state funding, the center discontinued many of its research and teaching programs in 1995, but its World Wide Web site located at
http://artsnet.heinz.cmu.edu:70/1/csa/
continues to be maintained and is one of the best and most readily available resources available on art-related health hazards.
The CSA site, which is maintained by the New York Foundation for the Arts, consists of articles, data sheets, and information on other resources that deal with the health risks faced by artists. To make it easier to determine what exposures a particular artist should be wary of, the center provides links to groups of papers divided into separate sections for visual artists, school children, museum curators, and performing artists. All of these can be accessed by following the Art Hazards Menu link on the center's main menu. Through this link, users can connect to another link labeled
Arts Hazards News
Issues. Published five times a year until the 1995 funding cuts, the
Arts Hazards News
was the CSA newsletter, providing artists with timely updates on the dangers they faced. Since publication has stopped, the CSA has added all back issues to their Web site, and these newsletters continue to be a good source of information on topics ranging from the safety of different materials to alternatives to using toxic chemicals.
Information on specific toxic materials such as solvents and flammables can be found by following the General Hazards Menu link on the center's main menu. Information on multiple chemical sensitivity, indoor air quality, and fire prevention can also be found here. The Precautions Menu link on the CSA home page takes the user to a list of links to documents on topics such as respirators, gloves, ventilation, and other means of avoiding contact with hazardous substances. The Laws & Regulations Menu link connects users to 15 articles that discuss National Institute for Occupational Safety and Health and Occupational Safety and Health Administration standards for workplace safety. The CSA home page also allows access to other related World Wide Web and gopher sites via two links on the main menu.
The last item on the CSA main menu is a link to an internal search engine that allows users to search for key words in the titles of documents on the CSA site.
Last Update: March 19, 1997