The challenges of emerging illness in urban environments: an overview.

The New York City West Nile outbreak is an important case study for examining several medical and public health issues raised by the specter of emerging illnesses in urban areas. Five specific issues are addressed in this issue of the Journal of Urban Health: ecosystem health, vector (e.g., mosquito) control, risk communication, public health infrastructure, and parallels between this outbreak and bioterrorism.

Health risks posed by use of Di-2-ethylhexyl phthalate (DEHP) in PVC medical devices: a critical review.

BACKGROUND: Polyvinyl chloride plastics (PVC), made flexible through the addition of di-2-ethylhexyl phthalate (DEHP), are used in the production of a wide array of medical devices. From the late 1960s, leaching of DEHP from PVC medical devices and ultimate tissue deposition have been documented. METHODS: A critical review of DEHP exposure, metabolism, and toxicity data from human and animals studies was undertaken. A brief analysis of alternatives to DEHP-plasticized PVC for use in medical device manufacture was completed. RESULTS: DEHP leaches in varying concentrations into solutions stored in PVC medical devices. Certain populations, including dialysis patients and hemophiliacs may have long-term exposures to clinically important doses of DEHP, while others, such as neonates and the developing fetus, may have exposures at critical points in development. In vivo and in vitro research links DEHP or its metabolites to a range of adverse effects in the liver, reproductive tract, kidneys, lungs, and heart. Developing animals are particularly susceptible to effects on the reproductive system. Some adverse effects in animal studies occur at levels of exposure experienced by patients in certain clinical settings. DEHP appears to pose a relatively low risk of hepatic cancer in humans. However, given lingering uncertainties about the relevance of the mechanism of action of carcinogenic effects in rodents for humans and interindividual variability, the possibility of DEHP-related carcinogenic responses in humans cannot be ruled out. CONCLUSIONS: The observed toxicity of DEHP and availability of alternatives to many DEHP-containing PVC medical devices presents a compelling argument for moving assertively, but carefully, to the substitution of other materials for PVC in medical devices. The substitution of other materials for PVC would have an added worker and community health benefit of reducing population exposures to DEHP, reducing the creation of dioxin from PVC production and disposal, and reducing risks from vinyl chloride monomer exposure.

Poverty and ill health: physicians can, and should, make a difference.

A growing body of research confirms the existence of a powerful connection between socioeconomic status and health. This research has implications for both clinical practice and public policy and deserves to be more widely understood by physicians. Absolute poverty, which implies a lack of resources deemed necessary for survival, is self-evidently associated with poor health, particularly in less developed countries. Over the past two decades, economic decline or stagnation has reduced the incomes of 1.6 billion people. Strong evidence now indicates that relative poverty, which is defined in relation to the average resources available in a society, is also a major determinant of health in industrialized countries. For example, persons in U.S. states with income distributions that are more equitable have longer life expectancies than persons in less egalitarian states. There are numerous possible approaches to improving the health of poor populations. The most essential task is to ensure the satisfaction of basic human needs: shelter, clean air, safe drinking water, and adequate nutrition. Other approaches include reducing barriers to the adoption of healthier modes of living and improving access to appropriate and effective health and social services. Physicians as clinicians, educators, research scientists, and advocates for policy change can contribute to all of these approaches. Physicians and other health professionals should understand poverty and its effects on health and should endeavor to influence policymakers nationally and internationally to reduce the burden of ill health that is a consequence of poverty.

Hospitals and plastics. Dioxin prevention and medical waste incinerators.

CHLORINATED DIOXINS and related compounds are extremely potent toxic substances, producing effects in humans and animals at extremely low doses. Because these compounds are persistent in the environment and accumulate in the food chain, they are now distributed globally, and every member of the human population is exposed to them, primarily through the food supply and mothers' milk. An emerging body of information suggests that dioxin contamination has reached a level that may pose a large-scale, long-term public health risk. Of particular concern are dioxin's effects on reproduction, development, immune system function, and carcinogenesis. Medical waste incineration is a major source of dioxins. Polyvinyl chloride (PVC) plastic, as the dominant source of organically bound chlorine in the medical waste stream, is the primary cause of "iatrogenic" dioxin produced by the incineration of medical wastes. Health professionals have a responsibility to work to reduce dioxin exposure from medical sources. Health care institutions should implement policies to reduce the use of PVC plastics, thus achieving major reductions in medically related dioxin formation.

Medical responsibility and global environmental change.

Global environmental change threatens the habitability of the planet and the health of its inhabitants. Toxic pollution of air and water, acid rain, destruction of stratospheric ozone, waste, species extinction and, potentially, global warming are produced by the growing numbers and activities of human beings. Progression of these environmental changes could lead to unprecedented human suffering. Physicians can treat persons experiencing the consequences of environmental change but cannot individually prevent the cause of their suffering. Physicians have information and expertise about environmental change that can contribute to its slowing or prevention. Work to prevent global environmental change is consistent with the social responsibility of physicians and other health professionals.

The poor quality of early evaluations of magnetic resonance imaging.

To study the quality of early research on the clinical efficacy of diagnostic imaging with magnetic resonance, we assessed 54 evaluations published in the first four years after introduction of this modality using ten commonly accepted criteria of research methodology. The terms sensitivity, specificity, false-positive or false-negative, accuracy, and predictive values were used infrequently. Nineteen percent of the evaluations used three terms appropriately, 48% used one or two terms, and 33% used none. Data were presented appropriately for one or more of the five terms in 59% of evaluations. A "gold standard" comparison with the results of an independent procedure, such as surgical or autopsy findings, was presented in 22% of evaluations. Results of another imaging procedure were described in 63% of evaluations. Only one evaluation clearly described a prospective study design, although 11 evaluations apparently were planned in advance. Not one evaluation contained an appropriate statistical analysis of the distributions of quantitative readings, "blinded" image readers to diagnosis or other test results, measured observer error, or randomized the order of magnetic resonance imaging and other imaging procedures. We conclude that health care professionals paying for expensive innovative diagnostic technology should demand better research on diagnostic efficacy.

An international survey of medical school programmes on nuclear war.

Many medical organizations have acknowledged the responsibility of doctors to educate health professionals and the public about the medical, social and ecological consequences of nuclear war. Medical schools have begun the development of programmes on these topics. A total of 1130 medical schools in thirty-one countries were surveyed about their presentation of nuclear-war-related subject matter. Eighty-three (49%) of the 168 schools that responded indicated that they offered an activity on medical aspects of nuclear war. Thirty-two per cent of the programmes consisted of one or more hours in an existing required course. Twelve per cent offered an elective course solely concerned with nuclear war. Although only 15% of the schools responded many of the replies indicated interest in learning more about the programmes of other schools and inquired if curriculum or teaching materials were available. Through the survey it was learned that textbooks and other learning resources have been prepared. Survey information suggests that knowledge of nuclear weapons effects is associated with a reluctance to countenance nuclear war.

Nuclear weapons, nuclear war and the health professions. Curriculum development in medical schools.

The role of health care professionals in educating the public and policymakers about nuclear weapons, nuclear war and issues involved in preventing thermonuclear warfare is increasing. It is based on the professional and ethical responsibility to promote public health and prevent epidemic disease and death wherever possible. In the case of nuclear war, which has been called "the final epidemic," increased public knowledge is a primary method of working for its prevention. Policymakers in the United States and internationally are turning to physicians and scientists with important questions about the effects of nuclear war, questions about human behavior under stress, questions about long term ecological effects and survivability, and questions about technical aspects of the weapons themselves. The profession itself is asking questions about its proper role in these issues and the ethical basis for political activity on behalf of public health. Thus, concerned physicians are seeking education in these areas. Many medical schools have developed courses, one of which is described here. Consensus on a core curriculum has been achieved and curriculum materials are now available.