L’intrinseca verità delle statistiche
Negli studi molto ampi e complessi i risultati che si ottengono spesso dipendono dagli interessi economici che ci sono in gioco. Questi studi difatti possono essere effettuati solo da grandi organizzazioni che hanno il potere di pilotare i dati e i risultati secondo la propria convenienza.
La Considerazione o meno di alcuni parametri piuttosto che di altri, il restringimento o l’ampliamento delle condizioni iniziali, lo spostamento o la fissazione degli elementi in gioco, o altro ancora, fanno parte di tutto quel bagaglio statistico che è in grado, a mo’ di elastico, di produrre qualsiasi risultato statistico di cui si necessita.
In questo stato di cose, è chiaro che chi ha più denaro può dire quello che vuole e far passare per vere o efficaci anche cose palesemente false e fallimentari.
La chemioterapia appunto rientra in questa categoria.
Ci si potrebbe allora domandare: e se due colossi economici si dovessero trovare in antitesi, cosa succederebbe? La risposta è semplice: tutt’e due dimostrerebbero, statistiche alla mano, che ciò che è bianco per l’uno è nero per l’altro, oppure utile e benefico per l’uno è inutile o dannoso per l’altro e così via.
Se consideriamo, ad esempio, i derivati del petrolio e della sua lavorazione, tutti gli studi effettuati dalle grandi istituzioni e dalle multinazionali del farmaco, ci hanno insegnato che possiedono un alto potere carcinogenetico ecc. ecc.
La cosa però, vista dalla parte delle compagnie petrolifere, non sta in questi termini, anzi risulta chiaro come le persone esposte a queste sostanze ne ricevano addirittura un beneficio, sotto il profilo della salute.
Vale la pena di leggere, a tal riguardo, lo studio
Business Bias (riportato in fondo al presente articolo):
How Epidemiologic Studies May Underestimate or Fail to Detect Increased Risks of Cancer and Other Diseases
VALERIO GENNARO, MD, LORENZO TOMATIS, MD
Certo, le statistiche hanno e potenzialità illimitate; di sicuro però hanno la capacità di prenderci in giro come vogliono, in funzione del committente.
Queste sono le statistiche dell’oncologia!
Dr. Tullio Simoncini
How Epidemiologic Studies May Underestimate or Fail to Detect Increased Risks of Cancer and Other Diseases
VALERIO GENNARO, MD, LORENZO TOMATIS, MD
In spite of claiming primary prevention as their aim, studies of potential occupational and environmental health hazards that are funded either directly or indirectly by industry are likely to have negative results. The authors present three common scenarios in which faulty design of epidemiologic studies skews results, and list 15 study design flaws that lead to results that are dangerously misleading with regard to both the evaluation and the improvement of public health.
Key words: epidemiology; industry influence; study design; public health.
Interests other than those concerned with the protection of public health - in particular, personal ambition or economic profit - can heavily affect biomedical research,(1) and cancer rescarch in particular(2-5) There is ample evidence that, in spite of claiming primary prevention as their aim, occupational and environmental studies that are directly or indirectly sponsored by multinational corporations almost invariably lead to negative results. In such studies the real risk of disease in subjects exposed to harmful factors is often underestimated.
One way this is done is by indicating a safe environmental situations that very likely present risk. For example, in petrochemical and refinery-based epidemiologic studies conducted (or simply supported) by corporations workers potentially exposed to about 50 substances classified as toxic, mutagenic and carcinogenic (9) are regularly declared healthy (10-11). There are several reasons to question these results.
Studying the scientific literature oriented to the identification of the disease risks in strategically and economically relevant activity sectors such as oil refineries and petrochemicals, it is common to observe a statistically significant reduction of the observed/expected ratio of cases (dead or ill) among exposed workers (vs unexposed). This may, of course, occur because there is no exposure at all, but in other instances the real cause of the negative results-that is, the absence of an association between exposure and adverse health effects-may reside in the epidemiologic study design.
We present three scenarios, examples of which have been observed in recent studies, in which real risks of disease are underestimated. In addition we put forth 15 points, some of which are borrowed from a nearly 25-year-old analysis, (12) that are both critical and dangerously misleading with regard to both the evaluation and the improvement of public health. As reanalysis of specific data sets are not available, we cannot, however, make any direct evaluation or simulation of specific studies.
If exposed and unexposed workers are not separated, the automatic and obvious; consequence is a large underestimatíon of the real magnitude of risk among the exposed workers (misclassification error). This error might be negligible (statistically, not ethically, of course) only if and where the proportion of unexposed workers is not relevant (in terms of size, Person-years, etc.). Only the classification of the whole cohort in the homogeneous subgroups of workers, therefore, will permit an estimate of the real risk magnitude.(13)
A more serious misclassification bias occurs when exposed diseased workers are classified as unexposed controls. (14) This is often the case in studies of U.S. refinery workers, among whom the most heavily exposed workers are often “contract workers” who may work at a refinery or refineries cleaning tanks or installing insulation but who are not regular “employees" of the refinery. This “problem” has been known to the American Petroleum Institute (API) for more than 40 years. In 1958, the American Petroleum Institute (API) contracted with Dr. Robert Kehoe to design “An Epidemiologic Study of Cancer among Employees in the American Petroleum Industry.”14 In describing worker exposure classification Kehoe noted:
It was quickly discovered as various índustrial situations were studied also that job titles differed greatly from company to company and indicated little if any relationship to the degree and kind of hazard. Men charged with the actual operation of the equipment, for example in the petroleum industry, may have very little or no contact with either petroleum or the various refined products, but the samplers and maintenance personnel may have frequent and heavy exposures. At the same time, maintenance and labor classifications may work in all parts of the refinery or, equally common, be assigned for a significant period of time to a single area. In reviewing the effect of technical changes in the refining processes on the exposure factor, one is immediately impressed by the fact that this is an extraordinarily, fluid and dynamic industry. New processes evolve constantly, and this has been particularly true in recent years as companies moved rapidly from 'batch' type of operations to essentially 'assembly line' procedures. With this evolution, the degree and kind of contact change markedly. Maintenance problems are reduced and even presently widely-spaced 'turn arounds' are being substantially subcontracted by many companies. (It must be admitted that, although this development may diminish the exposure hazard for the refinery worker, it may be concentrating and augmenting the danger to the employees of companies specializing in this service type operation.)
Consequently, even if accurate and reliable occupational records were obtainable, the local situations are constantly changing and improving so that the exposures of today are much less than those ten years past, and it can be predicted confidently that they are probably much greater than those of ten years hence.
Unfortunately, instead of trying to correct this problem, API-funded researchers have capitalized on this phenomenon to generate study findings that appear to show that workers potentially exposed to all kinds of known carcinogens and other toxins live longer than unexposed population controls. This is in part due to the fact that exposed contract workers with disease are moved from the exposed diseased category (the "a"box) to the unexposed disease category. For example, Otto Wong stated that a contract worker with leukaemia (a plaintiff in a lawsuit against Mobil) who worked at a Mobil facility cleaning reactor vessels but did not work as a regular employee for Mobil would not be categorized as a Mobil worker. On the other hand, Wong stated that a Mobil lawyer whose office was located at the same facility would be included in the exposed group. (15)`
For rare diseases, such non-random misclassification that switches exposed-diseased workers to the unexposed-disease category can easily produce results that show that “exposure" is protective. This is in fact what Wong has often found.(16)
1f we compare illness frequencies among exposed workers with those in the general population (which is normally less healthy than the workers when hired and even later) we create a “healthy-worker effect" (HWE) with the consequent related comparison bias. The HWE is too often considered inevitable. As a matter of fact, ít is not only an effect, a bias, or finally, an epidemiologic artefact, but a serious error that can be avoided by an epidemiologic study design in which an internal comparison between exposed and unexposed workers is performed correctly. As a matter of fact, an unexposed group of oil refinery workers is often readily identifiable within the plant under study.
When two of these errors occur at the same time, a “negative" result is practically certain: a protective effect will be demonstrated, and the studied workers will show a reduction of their risk with a lower-than expected number of observed cases (dead or ill).
In addition, the reduction of this risk might also be statistically significant when the 90% confidence ínterval (CI) - instead of the conventional 95% CI-is calculated around the point estimate (Le, RR, SIR, SMR). In fact, the conventional 95% interval might not show any significant reduction due to its larger interval.
When we asked why this questionable methodologic approach is used, we received different answers: the data were analysed in many ways (and that is often true); this way of analysis is usual (and .again, this is often true); other approaches were not available; and, hard to believe, a different approach would be too costly.
In the light of such premises, we have identified 15 elements that, when present in epidemiologic studies, may lead to falsely negative results.12 These elements do not meet the criteria for good epidemiologic practice oriented to the improvement of public health.
(ERRORS TO BE AVOIDED)
I. Privilege the use of descriptive instead of analytic statistics, and the adoption of cross-sectional instead of longitudinal epidemiologic studies;
2. fail to study the single homogeneous subgroups of
workers (in terms of exposure);
3. consider only the exposure to one single substance, ignoring the possibility of exposure to multiple substances and their interaction;
4. keep the unexposed and exposed workers mixed
(creating a dilution effect);
5. compare the exposed workers, who are usually selected according to their overall positive health condition, with the general population (instead of unexposed workers), creating a healthy-worker effect (and comparison bias);
6. take into consideration only one single disease (or disease family, e.g., cancers) rather than all diseascs;
7. maintain desegregation of homogenous pathologies, thus making statistical significance more difficult to achieve;
8. fail to study reversible symptoms or serious sentinel abnormalities;
9. study neoplastic effects (usually having medium long latency periods) at follow-up periods too short to allow for their development;
10.compare effects on the same target organ between groups of individuals exposed to different agents (c,g., asbestos workers vs tobacco smokers) having the same target (c.g., lung);
11 interpret the absence (or inadequacy) of both environmental (and biological) monitoring and epidemiologic studies as evidence of absence of exposure and negative health effects;
12.keep the measurements of exposures separated from the measurements of health effects;
13 privilege statistical significance rather than biological significance, and consider the results of large and multicentric studies more important than other factors (biology, exposure, etc.);
14.use the conventional two-sided statistical test instead of the one-sided statistical test, which appears to provide the greatest reassurance against missing an exposure-related effect; and, last but not least,
15 use univariate analysis instead of a multivariate analysis that permits the simultaneous study of all the relevant variables (c.g., age at hire, sex, area job, calendar period, length of employment, latency, etc.).
The scientific evidence currently available suggests that epidemiologic studies addressing the identification of health risks for workers occupationally exposed to noxious agents, as well as for residents in polluted areas, rarely fulfil the standards of scientific rigor and commitment to the principles of public health protection if they are sponsored by strong economic interests. For instance, studies of workers in oil refineries conducted with total economic independence have identified possible environmental and health risks associated with exposures to more than 50 substances classified as toxic, mutagenic, and carcinogenic, such as asbestos, arsenic, benzene, chromium, nickel, polycyclic hydrocarbons, and silica. The LARC has therefore evaluated exposures in oil refineries as probably carcinogenic to humans (9) By contrast, other studies undertaken within the same areas of industrial production, supported by industry and of doubtful independence, do not report the existence of any risks.(6,10,11,15)
Epidemiologic investigations on oil refinery workers carried out in Liguria (Italy) have identified specific asbestos-related tumors,-such as pleural (18-19 and lung (13) tumors, a finding that was subsequently and independently confirmed in Canada .(20) These findings were initially ignored and/or openly disputed, but were later accepted. (15) Only Kaplan (21) had previously registered an excess of mesotheliomas in these workers.
A review of studies of effects of exposures to selected chemicals (alachIor, atrazine, formaldehyde, and perchloroethylene) shows that 60% of such studies conducted by non-industry researchers found these chemicals hazardous, while only 14% of industry-sponsored studies did so. (15-22) There is a legitimate doubt that at least part of these studies effectively pursued the actual identification of specific risks, or complied with rigorous scientific criteria. Such studies have contributed to a harmful delay in the adoption of preventive measures and have down played the significance of primary prevention, especially in developing countries. (23)
The power of the limited number of multinational corporations is proven by the fact that they operate worldwide, with over 700 petroleum refineries where they employ about 1,200,000 workers. Additional workers are employed in related industries, where about 2,500 different products such as lubricants, bitumen (residual oils), fueIs, solvents, fabrics, plastics, disinfectants, perfumes, etc., are produced. (24) Most studies sponsored by the companies owning the refineries have provided reassuring results. (6-15) Given the way in which the data were assembled and analysed, however, they are definitely not reassuring.(7)
Based on this background, there is an urgent need for strengthening economically and intellectually independent scientific research that is explicitly oriented toward primary prevention (i.c., the protection of public health) and free from any business bias or bias due to any vested economic interest. We suggest, therefore, that qualified independent scientists be allowed to reanalyse the original data sets of studies that either 1) have been conducted or supported by sponsors having strong conflicting economic interests or 2) report negative results or a protective effect where there is a reasonable suspicion (a priori or suggested by other studies) of the presence of increased risk of an adverse health effect.
The authors thank Marcello Ceppi, Fabio Montanaro, and Stefano Parodi for their helpful comments, and David Egilman for his comments and substantial contribution to Scenario 2.
I. Bekelman JE, Li Y, Gross CP. Scope and impact of financial conflicts of interest in biomedical research JAMA. 2003;289:454-65.
2. Tomatis L. Can social injustice be compensated adequately? Epidemiol Prev. 1994;18:135-40.
3. Tomatis L. Prírnary prevention protects human health. Ann NY
Acad Sci. 2002;982:190-7.
4. Ludwig ER, Madeksho L, Egilman D. Re: Mesotheliorna and lung tumors attributable to asbestos among petroleum workers. Arnj Ind Med. 2001;39;524-7.
5. Rosenstock L, Lee Lj. Attacks on science: The risks to evidenee
based policy. Am j Public Health 2002;92:14-8.
6. Satin KP, Bailey Wj, Newton KL, Ross AY, Wong 0. Updated epidemiological study of workers at two California Petroleum Refineries, 1950-95. Occu. Environ Med. 2002;59:248-56.
7. Parodi S, Montanaro F, Ceppi M, Gennaro V. Post script letters. Mortality of petrolcum refinery workers- Occup Environ Med. 2003;60:304-5. <http://ocm.bmjjournals.com/cgí/content/fu11/60/4/304>. 17.
8. Gennaro V, Parodí S, Ceppi M, Montanaro F. Cancer in petroleum refineries: absence of risk or misclassification? Epidemiol Prev. 2003;27:173.
9. International Agency for Rescarch on Cancer (IARC). Occupational exposures in petrolcum refining; crude oil and major petroleum fuels. Evaluation of Carcinogenic Risks to Humans.1989;45.
10. Raabe GK Collingwood KW, Wong 0. An updated mortality study of workers at petrolcum refinery in Beaumont, Texas. Am j Ind Med. 1998-133:61-81.
11 Lewis RJ, Gamble JF, Jorghensen C. Mortality among three refinery/petrochemical plant cohorts. 1. 1970 to 1982 actíve/ terminated workersj Occup Envíron Med. 2000;42:721-9.
12 Hernberg S. “Negative" results in cohort studies--how to recognize fallacies. Scandj Work Environ Health. 1981;7:121-6.
13.Gennaro V, Finkelstein MM, Ceppi M, et al. Mesothelioma and lung tumors attributable to asbestos among petroleum workers Amj Ind Med. 2000;37:275-82.
14 Kehoe R. An Epidemiologic Study of Cancer among Employees in the American Petrolcum Industry. Report to the American Petroleum Institute, March 1958, Bates Number 9 1 1230BinEuIM 02197.
15.Wong 0. Deposition taken in jorge TaUey Plaintiff vs. Safety Klen\ Corporation, No. 784605, May 7, 1999.
16.Wong 0, Raabe GK- A critical review of cancer epidemiology in the petroleum industry, with a meta-analysis of a combined database of more than 350,000 workers, Regui Toxicoi Pharmacol, 2000 Aug;32 (1):78-98.
17 Lemen RA. NIOSH. Testimony on formaldehyde. 1986.
18 Gennaro V, Ceppi M, Fontana V, et al. Is the oil refinery piant a dangerous workplace for pleural cancer? Some epidemiological evidence. Eleventh biennial meeting of the European Association for Cancer Research. Eur J Cancer. 1991; 27 (suppl 3): S47.
19.Gennaro V, Ceppi M, Boffetta P, et al. Pleural mesothtlíoma and asbestos exposure among Italian oil refinery workers. Scand j Work Environ Health. 1994;20:213-5.
20.Fínkolstein MM. Asbestos associated cancers in the Ontario refinery and petrochemical sector. Amj Ind Med. 1996;30:610-5.
21 Kaplan S1). Update of a mortality study of workers in petroleum refineries. J Occup Med. 1986;28:514-6.
22. Fagin D, Lavelle M. Center for Public Integrity. Deception: how the chemical industry manipulate sciences, bends the law and threatens your health. Seacaucus, NJ: Birch Lane Press, 1997:57.
23. International Agency for Research on Cancer (IARC). Occupational cancer in developing countries. IARC Scientific Publication 1994. N. 129.
24. International Labour Office. Employment and industrial relations issues in oil refining: report for discussion at the tripartite meeting on employment and industrial relations issues in oil refining. Geneva, Swítzerland: ILO, 1998.
David Egilman, MD, MPH, à Clinical Associate ~roféssor, in the Department of Community Health at Brown Unimrsity. He is the faunder and chair of the board of the Massachusetts-based nonprofit, Global Health through Education, Training and Seriice, an organization dedicated to improi4ng health in developing countries' through innovations in education and service. Dr. Egilman has published widely on issues of occupational health and sa1éty~ includíng the corporate corruption of science in the asbestos, beryWum, pharmaccutical, and other industrics. He is frequendy asked to serve as an expert witness by both plaintiffs and defendants in toxic tort and other litigation, including fitigation involving several of the industrics discussed in the articles authored and co-authored by him in this volume.
Susanna Rankin Bohme. AM, is a doctoral candidate at Brown University, Department of American Civilization, where she received her Master's Degree in 1999. Her work at Brown focuscs on the intersections of health and globalization. Her dissertation looks at the international pesticide trade and worker and consumer anti-pesticide activism in the United States and Central America. She has co-authored papers on the ínfluence of the asbestos industry on science, the history of consumer and labor warnings, and the ideology of health and science. She. works as a rescarcher at Never Again Consulting in Affleboro, Massachusetts.
Marion Billings received her Bachelor of Arts degree at Brown University in 2004 in Human BioIogy~ with a focus in human health and discase. She has done critical research on the epidemiology of the association between asbestos containing automobile brake pads and mesothelioma. In addition she has done extensive work ín New York C.Naty with the newly emer~ cohort of adolescents with perinatally acquired HIV. She is currendy completing her Master's Degree in Public Health afthe London School of Hygiene and Tropical Medicine, in the United Kingdom.
Valerio Gennaro, MD, PhD, currendy serves as Director of the Liguria Operative Center of the Nationai Mewtheliorna Registy, Consultant at the Senate (Italian Republic), and Executive medicai epidemiologist at the Descriptive Epiderniology and Cancer Registry Unit in the Epidemiology and Prevention Department of the National Cancer Research Institute. He is President for the Genoa Province of the Associazione Italiana Medici per l'Ambiente [International Society of Doctors for Enviroriment].
Peter Infante. DDS. DrPh, is Adjunct Professor of Eniirorimental and Occupational Health at George Washington University, School of Public Health and Health Seriices. He has a Doctor of Public: Ilealth degree frorn the Department of Epiderniology, Uníversity of Michigan School of Public Health. He is a Fellow of the American College of Epidemiology and of the Collegium Rarnazz
ini. For 27 years, he conducted research into the cancercausing effects of toxíc substances found in the workpiace, and he is internationally recognized for identifying two causcs of human cancer. He has served on numerous national and internatíonal panels and working groups related to the identificafion of causcs of human cancers, including the International Agency for Rescarch on Cancer, the National Cancer Institute, the Presídent's Cancer Panel, the Office of Technology Assessmen t of the U.S. Congress and the National Academy of Sciences Committec on Toxicology. Dr. Infante has served as aà expert witness in toxics-related litigation.
Michael E jacobson, PhD, is co-founder and Executive Director of the Center for Science in the Public Interest (CSPI), a nonprofit health-advocacy organization. aPI advocates for improved public polícies and corporate practices related to nutrition, food safety, alcobol, and other issues. Its educatíon efforts include media advocacy and publication of the *Nutrition Action Healthletter» (circulatíon 900,000) and reports. Sínce its foundíng in 1971, jacobson and C-SPI have led the efforts > to win passage of the Nutrition Labeling and Education Art, which requires nutrition infarmation on most food labels; laws requíring warníng notices on alcoholic beverage labels and setting a federal definition for 'organic: food.»
W~ Kovanlk, PhD, is Professor of Media Studics at Radford University in southwestem VùZúùa, where he teaches science and envirownent writing, media history, and Media law. He is a graduate of VirZinia Commonwealth UniVersitY (1974), the University of South Carolina (MA, 1983), and the University of Maryland (PhD, 1993). Kovarik also has served on the facuity at Vu~ Tech and the University of Maryland. Ifis professional experience as a journalist includes reporting and editing forjack Anderson, the Associated Press, The chm~ (se.) e~rL-r, 77w Baltimm Sùi~, lime-111è Books, Bu~ publishers, and the National Center for Appropriate Technology.
jock MeCulloch, PhD, ha% worked as a Ugislative Rescarch Specialist for the Aust~ parliament and has taught at vafiotes universities. His principal research interests are in the history of medicine. He is thc author of seven books, including a hístory of the ashestos industry in Australia called A~s: ILT Human Cost (1986) and Asbe_Sto.v Blues (2002), a study of blue asbestos mining in South Africa. He is presendy writing a global history of the ashestos índustry. Over the past 15 years Dr.McCuUoch bas on four occasions worked as a consultant for litigants.
Phyflis j. Mullenix, PhD, under a National Science Foundation Fellowship Award, reccived a doctorate in Pharmacology from. the University of Kansas Medicai Center in Kansw City in 1975. After completing postdoctoral training in enkironmental medicine at the johns Hopkins School ofSygine and Public Health in Baltimore, sheheld academic appoíntments at Boston's Children's Hos, pital Medical Center and the Harvard School of Medicíne
in the departrnents of Psychiatry, Neuropath«logy, and Radiation Oncology. Her many original rescarch publications focused on detection of beliadoral dysfunction induced by perinatal expostire to drugs and environrnental pollutants, and they led to the development of the first computerized pattern-recognition system that evaluated abnormal motor pattems related to clinícal disorders. Dr. Mullenix has served as an expert witness in fluoriderelated litigation,
Rajeev Patel, MSc, PhD, is currently a po-,tdoctoral fellow at the Centre for Civil Society, School of Development Studics, University of KwaUlu-Natal, South Affica, where he rescarches agrarian change. He has degrees from the Universitics of Oxford and London, and Comell University. He previously worked with the Institute for Food and Development Policy (Food First) in Oakland, California, and is currently writing a book on the global food system.
Enika RosenthaI, JD, MSI, is an attorney with Earthjustce's international department, and has consulted for the Pan American Health Organizatíon, the Pesticide Action Network-Latin America, and Development & Equíty, a consulting firm that analyzcd pesticide issues for the Danish Agency for Intemational Development (DANIDA).
PeteT Rosset, phD, is an agroccologist with a doctorate in biology from the University of Michigan. He is past director of the Institute for Food and Development Policy (Food First), andis a researcher at the Center for the Study of Rural Change in Mexico, an associate at the Center for the Study of the Americas, in Berkeley, CA, and a-visiting scholar in EnNironmental Science, Policy and Management of the Universky of Calffornia at Berkeley.
J~er Sass, PhD, is a Senior Scientist at the Natural Resources Defense- Council. She has spent over a decade as a laboratory researcher, in biomedical rescarch. Her areas of study include neurobiology, cell and molecular biology, and toxicology. Research specifics include study of the effect of mercury on neural development, study of the effect of alumínum on neurobiochemistry, and study of stress proteins (chaperones) in embryonic development. Her PhI) was completed in 1998, from. the University of Saskatchewan, in the Department of Anatomy and
VOI 11 /NO 4, OCTJDEC 2005 o www.ijoeh.com
Cell Biolooy. Her postdoctoral rescarch was completed in 2000, at the University of Maryland, Baltimore, in the Program of Human Health and the Ensironment.
Caroline Snyder, PhD, did her undergraduate work at Radcliffe College and graduate studíes at Han-ard University. She is Professor Emerita at the Rochester Institute of Technology, where she was one of the first faculty members nationwide to design and teach Ensironmental Studics and Environmental Science courses. Before retiring, she chaired the Department of Science, Technology, and Society. In 2003, the New HampshireSierra Club awarded Snyder the Consevration ActíNist Award «for her relentless efforts to raise the consciousness of the publíc and legislators, both national and local" to the problen-L% related to the land applícation of munícipal scwage sludge. She is a charter member of the Union of C3oncerned Scientists. Dr. Snyder has scrved as a volunteer expert witness in sludgerelated litigation.
Skip Spitzer, MA, is Program Coordinator at Pesticide Action Network North America (PANNA). He holds an MA in sociology from the University of California, Santa Cruz. Beforejoining PANNA, he taught sociology at several California colleges and universitics. Mr. Spítzer has worked for almost 25 years as an acti-dst on a wide range of socíaI and environmental issues. He is also an acti-vist skills trainer and a software engincer.
Robert Torres, PhD, is an Assistant Professor of Sociology at St. Lawrence University~ His rescarch interests include the political economy of the global agro-food system and the social ímplica-tions of genetically modified organi.sms in agriculture.
Lorenzo Tomatis, RD, has served as Chairman of the Scientific Council of the International Society of Doctors for the Environrnent (ISDE) since 1999. He was Director of the International Agency for Re~.ch on Cancer (IARC), Lyon, France, fi-om 1982 to 1993, and Scientific Director of the Institute for Mother's aRd Child Health, Trieste, Italy, from 1996 to 1999. john Zorabedian has worked as a jo urnalist covering local and national govemment, economics, and sports. He reccived his RA from Wesleyan University in 1999. He is currently a rescarcher at Never Again Consulting.