Environmental Medicine: From the Concert Hall to the BarracksON THE COVERViolations of Informed Consent During WarEffects of Noise on HearingNeedlestick Injuries Among French Medical StudentsHuman Health and the Environment: Are Physician Educators Lagging Behind? FREE

Few fields are as diverse as environmental and occupational medicine (EOM), which encompasses health issues at individual, community, and even planetary levels. The estimated disease burden attributed to environmental and occupational medical problems is considerable. Occupational injuries and illnesses in the United States may account for over 46,000 deaths and $171 billion in direct and indirect costs annually.¹ Nonoccupational aspects of environmental medicine have been the subject of a growing body of literature.² The World Health Organization now advocates for sustainable health, an approach based on the premise that technological development should not compromise human health or disrupt regional or global ecosystems.³

The industrialization of the United States during the 19th century marked a time of major development for EOM. As manufacturing became the country's primary economic activity, the first occupational safety regulations were established.⁴ More recent developments in EOM over the past half century were the AMA's approval in 1955 of certification in occupational medicine and passage in 1970 of the act that created the Occupational Safety and Health Administration (OSHA) and the National Institute for Occupational Safety and Health.⁴

As the new millennium approaches, many longstanding environmental health issues, such as high lead levels in buildings and hazardous working environments, remain unresolved, and new challenges continue to arise. Eli Merritt comments on the training of US medical students to meet these challenges, with special attention to recent curricular innovations. In his companion piece appearing on the MSJAMA Web site (http://www.ama-assn.org/msjama), Merritt critically examines the emerging field of global environmental medicine.

William Clark and Barbara Bohne review the association of noise exposure with auditory injury, reporting on the epidemiology, pathogenesis, and prevention of noise-induced hearing loss. Rosenthal and his colleagues present data on French medical students' experiences with blood exposure accidents. A piece by Joel Schofer explores the controversial ethical issues surrounding guidelines for obtaining informed medical consent in a wartime environment.

Trees by Patricia Wong, Stanford University School of Medicine.

War can radically alter the provision of medical care. The threat of biological and chemical warfare, such as troops encountered in Operation Desert Storm, for instance, raises ethical dilemmas rarely encountered in standard medical practice.

The Department of Defense (DOD) wanted to administer pyridostigmine and botulinum toxoid vaccine to protect soldiers from a possible toxic nerve gas or botulism attack by Iraqi forces. However, the DOD did not believe it was feasible to obtain informed consent from more than 500,000 military personnel.² It argued that some personnel might refuse to consent and that refusals could not be tolerated.¹ The DOD thus requested a Food and Drug Administration (FDA) waiver to allow administration of the 2 agents for unapproved use without informed consent.^1,7

The FDA granted the waiver, placing military physicians in the awkward position of having to administer an agent without the recipient's informed consent.^1,3- 4 Can this clear departure from standard medical ethics be justified in war?

Critics of the waiver believe that the DOD was acting in the interest of its own medical research. They cite the military's violation of the Nuremberg Code, a declaration governing human experimentation created in response to the Nazis' medical experiments during World War II.^1- 2,5 The Code states that the consent of the research subject is "absolutely essential."^1,7 Other critics have compared the DOD's decisions during Desert Storm to the Central Intelligence Agency's use of hallucinogens in the 1950s and 1960s as well as to Nazi physicians' use of unwilling experimental subjects during World War II.²

Defenders of the DOD's action disagree. A US District Court judge ruled that the Code was not applicable to the waiver because the DOD's purpose was not scientific.^1,7 Many authorities affirm that the DOD's use of the pharmacological agents was preventive.^2- 3,5 Other defenders of the military assert that the involuntary administration of protective agents was necessary to prevent thousands of potential casualties.² If soldiers had chosen not to take the agents, they may have been more susceptible to injury, put others at risk, and needed to be excused from combat, providing a relatively easy way for soldiers to avoid hazardous wartime duty.^1- 2,5

The events that took place during Desert Storm, ironically, provided evidence that voluntary administration of the agents was possible.⁵ While pyridostigmine was administered without informed consent, the botulinum vaccine was given on a voluntary basis, seemingly rendering the FDA waiver unnecessary.¹ If the vaccine was administered with informed consent, why not pyridostigmine?

One reason for the difference in administration could have been the relative safety of the 2 agents. Pyridostigmine has been FDA approved for use in myasthenia gravis since 1955, and the doses administered during Desert Storm are considered nontoxic.^2,5 In contrast, the vaccine remains an experimental agent and has never been approved by the FDA. Conflicting opinions exist regarding its safety, efficacy, and lack of FDA approval.^2,5,7 These differences may explain why a US Army institutional review board voted that informed consent was required to administer the vaccine during Desert Storm.⁷

Another reason for the difference may have been due to military intelligence. DOD intelligence reports indicated that the Iraqi arsenal included nerve agents.⁴ These reports may have made administration of pyridostigmine a greater priority than administration of the botulinum vaccine. What DOD reports claimed about Iraqi possession of botulism is unknown.

It has been said amid the clash of arms, laws are silent.^1,7 In this case, a fundamental medical concept, informed consent, was silenced by the clash of arms. Some intelligence information available at the time of Operation Desert Storm suggested that administering pyridostigmine without informed consent would have allowed the DOD to provide "significantly increased survival" to military personnel involved in the operation.⁴ Was the danger of attack, however, enough to warrant the violation of informed consent? Were military physicians, who must put priority on the success of the military mission and the needs of soldiers, ethically justified in administering medications to uninformed and nonconsenting recipients?⁶

Whether exception to basic ethical principles, such as informed consent, may be taken in wartime remains highly controversial. The ethical issues surrounding Operation Desert Storm raised questions about who should authorize nonstandard medical interventions during war. In the fall of 1998, Congress ruled that any decision to use unapproved drugs or vaccines in wartime must be made by the president of the United States.⁸

The author acknowledges constructive criticisms from Edmund G. Howe, MD, JD, and George J. Annas, JD, MPH, during the preparation of this article.

Few would deny that we live in a noisy world. Noise, whether a result of air traffic, crowded urban streets, personal stereos, or high-powered machinery, rifles, and shotguns, is one of America's most widespread nuisances. Excessive noise disrupts sleep, produces stress, impairs communication, and, in high enough doses, causes significant noise-induced hearing loss (NIHL). Although roughly 25% of all Americans ages 65 and older suffer hearing loss, hearing loss is not part of the natural aging process. Much hearing loss in older Americans is due to preventable, noise-induced wear and tear on the auditory system.

The ear is injured by noise in 2 different ways, depending on the type of exposure. High-level, short duration exposures exceeding 140 dB can stretch the delicate inner ear tissues beyond their elastic limits, then rip or tear them apart. This type of damage—acoustic trauma—occurs rapidly and results in an immediate, permanent hearing loss. The organ of Corti becomes detached from the basilar membrane, deteriorates, and is replaced by scar tissue. Because the ear is damaged mechanically by impulsive sounds, the maximum sound pressure level (SPL) is more important than the duration of the exposure. Noises in the environment capable of producing acoustic trauma usually come from explosive events, such as a firecracker detonating near the head (170 dB SPL), a toy cap gun fired near the ear (155 dB SPL), or a shotgun, high-powered rifle, or pistol shot (160-170 dB SPL).

Exposure to noise between 90 and 140 dB_A (dB_Adenotes a decibel measure with a filter that adjusts for human auditory sensitivity) damages the cochlea metabolically rather than mechanically and causes damage relative to the level and duration of exposure. Noise-induced hearing loss, in contrast to acoustic trauma, develops slowly over years, is caused by any exposure regularly exceeding a daily average of 90 dB_A, and proceeds in 3 stages.

In the first stage, sensory cells within the cochlea are killed by excessive exposure. These cells do not regenerate; they are replaced by scar tissue. In the second stage, after weeks to years of excessive exposure, hearing loss can be detected audiometrically. Early loss occurs in the high-frequency range, around the highest C note played on a piano. Speech comprehension is not significantly affected; therefore, this loss is seldom noticed unless hearing is tested for some other reason.

With continued exposure, the loss spreads to the lower pitches necessary for understanding speech. At this point, the third stage, the patient usually becomes aware of the problem and may seek medical attention. Unfortunately, much of the damage has already occurred (Figure 1).

Noise exposure in the workplace has been known for centuries to produce hearing loss. The US Department of Labor promulgated regulations in the 1970s and 1980s to protect the hearing of millions of Americans working in noisy environments. Current regulations require workers to be enrolled in a hearing conservation program if their daily exposure exceeds an average level of 85 dBA for an 8-hour day.¹

Recreational activities are also significant sources of noise. Clinical reports since the 1800s have documented hearing loss after exposure to shooting.² Americans collectively own more than 230 million guns,³ and over half of men in the American industrial workforce occasionally use guns.⁴ Because guns are so prevalent in our culture, shooting firearms is the most important source of excessive noise outside the workplace.

The logarithmic nature of the decibel scale makes it difficult to grasp the amount of acoustic energy in a single gunshot. The energy in a single report from a high-powered rifle or shotgun is equivalent to almost 40 hours of continuous exposure at 90 dB_A. In other words, 1 bullet equals 1 week of hazardous occupational noise exposure. An avid target shooter can produce 1 year's worth of hazardous occupational noise exposure in just a few minutes on the target range.

A large body of research details the noise exposure resulting from attendance at rock music concerts. One meta-analysis found that the average sound level at rock concerts was 103.4 dBA.⁴ Studies of temporary threshold shifts (TTS), which are indices of the ear's acclimatization to noise, have shown that after exposures to rock music most listeners sustain TTSs of up to 30 dB but recover within hours to days. Although the risk of sustaining permanent hearing loss from attending rock concerts is limited to those who frequent such events, rock concerts remain an important contributor to cumulative noise for certain individuals.

The increased use of personal stereos and CD players has led to concern about hazardous noise exposures, particularly for young listeners. The risk of hearing loss resulting from the use of headphones depends on several variables. These include the volume level selected, the time spent listening, the susceptibility of the individual's ear, and the extent of other noisy exposures. Although some stereos can exceed 120 dB_A, relatively few individuals exhibit patterns of use that significantly increase their risk of hearing loss.⁴

It has been suggested that prevention of excessive noise exposure would be more easily accomplished if the ear were to show its injury by bleeding after significantly damaging events. Instead, by the time functional hearing impairment is detected, injury to the auditory system is usually at an advanced stage. The key to prevention is therefore education.

Several organizations have provided educational curricula to science or health teachers to encourage healthy hearing habits for young ears.⁵ Axelsson and Clark⁶ have suggested that schools invite hearing professionals who can relate real life experiences that will help deliver the message to children.

In addition, federal law¹ requires education programs for employees exposed to high noise levels. Such programs are limited, however, in that they generally address workplace noise exclusively and are often available only to employees in high noise environments.

Physicians can help patients at risk for hearing loss by teaching them to avoid exposure to unwanted noise and to become judicious consumers of desired sounds. For example, physicians can recommend that patients avoid other noisy activities on the day of a rock concert. Research has shown that rest periods interspersed with an otherwise hazardous exposure can reduce auditory damage.⁷ Also, physicians can encourage patients to select events that are most enjoyable to them and then advise them to consider foregoing other noisy activities.

In situations where noise cannot be eliminated, patients should be advised to wear hearing protection. The 2 most commonly used types of protection are earplugs or earmuffs. Earplugs come in a variety of styles and sizes. Among their advantages are their small size, low cost, and relative comfort.

The other type of hearing protector is a muff that fits over the ear. Heavier and more protective than earplugs, muffs are also reusable and, when kept in good condition, can be considerably cheaper than disposable earplugs. However, a seal must be made between the earmuff cushion and the side of the head; any break in the seal renders the muff useless.

Individuals should wear hearing protection whenever they are exposed to loud sound and remember that the most effective type of plug or muff is the one that is actually used. Most individuals will find foam earplugs the protection of choice, because they are cheap, comfortable, disposable, and readily commercially available.

Noise-induced hearing loss is usually undetected until damage to the inner ear is advanced. Much is known about the deleterious effects of noise, but few efforts have been made to reduce noises at their source, to protect hearing in noisy environments, and to educate individuals on the importance of preserving hearing into old age. Hearing professionals can help patients understand the importance of preserving hearing into later life and the steps that can be taken to prevent NIHL.

Although the risk of human immunodeficiency virus (HIV) infection through occupational exposures to blood has received considerable attention,¹ relatively few studies have addressed blood exposure accidents (BEAs) among medical students.^2- 7 Guidelines for preventing needlestick injuries and administrating postneedlestick HIV prophylaxis are available,⁸ but these guidelines may be unfamiliar to medical students. This study investigates BEA exposure, BEA reporting, and use of universal precautions in a population of French medical students.

An anonymous questionnaire was administered to medical students in the fourth, fifth, and sixth years of training at Nice University, France. Students answered questions regarding the use of gloves, handling of sharps, and personal exposure to needlestick injuries (BEAs). Information on risk reduction behaviors, number of BEAs, BEA reporting, and BEA management was collected. Data were analysed with Epi-Info 6.04a and BMDP software.

Of 237 registered students, 200 (84%) completed the questionnaire. The overall prevalence of BEA exposure was 24%, with 37% of sixth-year students reporting at least 1 BEA. The mean number of BEAs per student was 1.4. Wound suturing and arterial puncture for blood gas studies accounted for 58% and 20% of BEAs, respectively. The remaining 22% of the cases occurred during intramuscular (2 BEAs), intravenous (2) or lumbar (2 ) puncturing, and other procedures (5). Of students who recalled having experienced a BEA, 39% had reported the incident to hospital personnel. Students most frequently indicated their inability to influence the outcome (40%) as the reason for not reporting a BEA. Several students reported that they did not know whom to consult (20%) or had been advised against reporting (20%).

Only 19% of students reported never recapping needles and always using a sharps container (Table 1). The decision to wear gloves was influenced by the procedure; most students used gloves for suturing, but not for intradermal or intramuscular injections. Of the students, 87% reported having received no information about universal precautions or BEAs during rotations.

Studies from several countries have found the prevalence of BEAs in medical students to be similar to that reported here.^2- 7 In this study, adherence to the universal precautions of using gloves and disposing of sharps was poor, suggesting a need to more carefully educate students on safe practices.

Perhaps the most disquieting finding pertains to the reasons students frequently did not report BEAs. A surprising number of students cited their inability to influence the outcome as a chief reason for keeping silent. This pessimism is at odds with data showing that postexposure prophylaxis may result in substantial reduction in the risk of HIV transmission.⁹ Furthermore, our finding that many medical students may perceive that they are being dissuaded from reporting BEAs or do not know to whom they should report such incidents suggests that students need more occupational risk management training in medical student education.

In the past 2 decades, numerous household and industrial products have been conclusively linked to human disease. Lead, carbon monoxide, and asbestos are the best known environmental toxins. Research has also established associations of in utero exposure to polychlorinated biphenyls with intelligence quotient deficits in children;¹ mercury in interior latex paint with neurologic disorders;² pollutants in drinking water with malignancies of the skin, lymph, and bone marrow.³ Most recently, dieldrin, an organochlorine used in pesticides, has been associated with a significantly increased, dose-related risk of breast cancer.⁴

In response to these accumulating data, 2 national organizations have taken steps to establish a permanent foothold for environmental medicine in US medical education. The National Institute of Environmental Health Sciences (NIEHS) has awarded over $13 million to US medical schools for the inclusion of environmental medicine in traditional academic curricula. And, the Institute of Medicine has recommended that all medical students acquire basic skills in eliciting an "exposure history" and a knowledge of the risk factors for environmental diseases.⁵

At Wayne State University School of Medicine, the Department of Family Medicine has put the Institute of Medicine recommendations into practice by instituting a "longitudinal integrated curriculum" that continues through all 4 years of medical school. In the first 2 years, faculty members give integrated environmental lectures in pathology, pharmacology, and public health/preventive medicine. During the third year, students view "Introduction to the Exposure History," a video that is followed by hands-on clinical applications during the family medicine clerkship. At the end of the third year, students take a clinical station-based examination that covers the most commonly occurring environmental diseases, including syndromes caused by exposure to lead, pesticides, asbestos, methyl mercury, organic solvents, carbon monoxide, particulate matter, bloodborne pathogens, polychlorinated biphenyls, and ionizing radiation (Sharon Popp, PhD, Maryjean Schenk, MD, Wayne State University School of Medicine, Division of Occupational and Environmental Medicine, written communication, March 1998).

Internists at the University of Maryland have also developed a program in environmental medicine. This group used its NIEHS grant to implement a 3-phase curriculum. The first year commences with a "kickoff session," in which student groups tackle 1 of 8 patient cases on environmental disease. Next, the faculty transforms the mezzanine of the medical school into an environmental medicine bazaar where students consult specialists at booths set up by outside organizations, such as the Maryland Occupational Safety and Health Administration and the Poison Control Center. The second year includes a 16-hour, problem-based learning course and a workplace visit. The faculty has also produced a 15-minute video on preventing environmental disease entitled "The Doctor Never Asks Me" as well as a sourcebook on curricular development (Janie Gordon, ScM, James P. Keogh, MD, University of Maryland School of Medicine, written communication, March 1998).

One of the most promising new academic projects in environmental medicine emphasizes regional epidemiology. The University of Alabama was awarded a 5-year NIEHS grant to study special needs of rural communities including mercury and dioxin poisoning of river-caught catfish, contamination of well water from nitrites in chicken manure, and cotton poison spills (John R. Wheat, MD, MPH, University of Alabama School of Medicine, written communication, March 1998).

Familiarizing students with environmental medicine early in their medical school training is a challenge for medical educators. Educational exposure on environmentally related disorders should begin early in medical school, when students are first introduced to pathophysiology and physical examination skills. Funding should be provided for research opportunities and curricular development. Programs such as those at Wayne State and the University of Maryland serve as models. Medical school administrators can help form committees that will study the literature on teaching environmental medicine. Finally, medical students need not wait for their deans and professors to take the lead. Rather, they should initiate curricular change on their own, realizing that physicians-in-training often perceive their own generation's challenges before their mentors do.

MSJAMA invites medical students to submit manuscripts for possible publication in future issues. We particularly welcome well-researched studies and essays on the following topics: international medical graduates in the US health care system, pain and chronic illness, new medical technologies, women in medicine, medical delivery during war, and the match process. Manuscripts should be less than 2000 words in length and formatted according to JAMA's Instruction for Authors. Submissions and questions should be directed to Editor, Jonathan H. Lin.