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Previous chapters of this book emphasize empowering individuals to participate in discussions about the significance and importance of medical benefits and environmental health risks. Those chapters stress the value of having the appropriate data in a format (e.g., Risk Characterization Theaters, absolute benefits and risks instead of relative benefits and risks) conducive to meaningful involvement. This book encourages the reader to determine his or her level of acceptable risk before making a decision regarding the benefits of screening tests and drugs or the risks from environmental contamination. But how do we determine our level of acceptable risk? How did the EPA settle on what should be the level of acceptable risk for exposure to cancer causing substances? How does the medical community determine what are the acceptable benefits and risks associated with screening tests and drugs? [ABSTRACT FROM AUTHOR]

Estuaries are among the most complex of all ecosystems. This is where salt water from the oceans mixes with fresh water from rivers to produce one of the most unique, important, and productive of all known ecological systems. They are found on continents and islands around the world and serve as nurseries for a multitude of aquatic vertebrates and invertebrates. For millions of years these habitats have evolved to allow organisms from many phyla to develop and thrive. The dynamic nature of estuaries and the intricate relationships between flora and fauna there make this type of ecosystem one of the least understood. Scientists from many disciplines continue to study how currents, temperature, salinity, dissolved oxygen, sediment deposition, metals, and organic compounds affect the abundance and distribution of aquatic life. Changing any of these factors will create a ripple effect throughout the estuarine system. Human-made changes which disturb the "natural order" of things generally produce a wide range of unanticipated and adverse impacts. [ABSTRACT FROM AUTHOR]

Baltimore's Inner Harbor is an historic seaport, the number one tourist attraction in the city, and an iconic landmark. It is a branch of the Patapsco River, which begins about fifty miles inland and terminates as a large tidal inlet of the Chesapeake Bay. Over the past few decades, the Harbor has been transformed from an industrial waterfront into one of the best examples of urban renewal in the country. Where oil refineries and storage tanks once stood along the banks of the Patapsco, upscale condominiums with spectacular water views now line the Harbor's edge. Factories that spewed out metals and organic pollutants have been replaced with chic retail stores and expensive restaurants. The river merges with the Chesapeake Bay, so yachts moored in the Inner Harbor have easy access to the recreational amenities of that world-class estuary. Indeed, the dramatic conversion of the Inner Harbor into Baltimore's jewel is one of the main reasons a prominent travel guide listed Baltimore as one of the ten most desirable tourist destinations in the US. [ABSTRACT FROM AUTHOR]

In order to get the best health care possible, you need to learn how to be your own patient advocate. One critical part of being a wise patient advocate is to build a partnership with your doctor. One of the key skills in building that partnership is being able to communicate with your doctor on medical issues. You need to develop a common language with your doctor so you can honestly and candidly discuss his recommendations to you. The day is long gone when the doctor-patient relationship was based on the doctor telling the patient what the diagnosis was and what the treatment plan was, and the patient accepting everything without question. [ABSTRACT FROM AUTHOR]

The word "radiation" often conjures up images of atomic bombs, nuclear power plants, and X-ray film. But human-made sources like these contribute only about 20% of our radiation exposure. In fact, we are bombarded with radiation quite regularly, and 80% of it comes from natural sources like cosmic rays and terrestrial radiation, including radon. In the US, radon probably contributes more than half of our radiation dose. Radon is a colorless, odorless, radioactive gas that is naturally present in rocks and soil all over the world. It is formed by the radioactive decay of uranium, and it seeps out of the ground into the air we breathe. Radon gas enters buildings through cracks in foundations and walls and openings around pipes and wires. Although radon gas dissipates quickly in outside air, there is less opportunity for it to disperse inside, so radon levels can build up indoors. The Environmental Protection Agency (EPA) and International Agency for Research on Cancer (IARC) have classified radon as a human carcinogen. There is concern that radon in homes might be causing lung cancer in the general population. Home inspectors often test for radon, and some people incur considerable expense to seal or ventilate a home with high radon levels. So a key question emerges: what is the lung cancer risk of inhaling indoor radon? [ABSTRACT FROM AUTHOR]

Ecological Risk Assessment (ERA) is a scientific approach used to determine the possible impacts of human activities on the environment. The EPA defines ERA as "the process that evaluates the likelihood that adverse ecological effects are occurring, or may occur, as a result of exposure to one or more stressors." These stressors might be contaminants like lead, non-native species like introduced plants, habitat modifications like new housing developments, or even changes in climate. In fact, a stressor is simply a change that modifies ecological systems such as lakes, streams, forests, and watersheds. The resulting ecological risks may be limited to a local scale, such as trout disappearing from a certain stream. Or they may be regional, at the scale of e.g., the Chesapeake Bay, or even world-wide, like global warming. [ABSTRACT FROM AUTHOR]

The chlorination of drinking water has saved literally millions of lives. Adding chlorine to water kills many disease-causing microorganisms and prevents people from getting sick from the water they drink. But the benefits of destroying these pathogens come at a price. Chlorine can also attack other substances in the water, transforming them into carcinogenic disinfection by-products (DBPs). On the one hand, pathogens in unchlorinated water make people ill. On the other hand, DBPs in chlorinated water present a cancer risk. This case study examines the trade-offs. [ABSTRACT FROM AUTHOR]

According to the National Cancer Institute (NCI), prostate cancer is the second leading cancer killer among men. An estimated one in six men will be diagnosed with prostate cancer in his lifetime, and more than 30,000 Americans die of the disease each year. As a result, the NCI and other national medical organizations emphasize the need for routine screening for prostate cancer in men over the age of fifty. Screening tests look for disease in people who don't have symptoms yet. Finding disease early can make treatment more effective, reduce suffering, and even prevent more serious problems. Screening has to be worth it: the occurrence of the disease and the chance of death must justify the effort and expense of screening.3 Clearly, prostate cancer is common enough and serious enough to justify screening. The prostate screening test has several components. It generally involves a digital rectal exam (DRE) and a blood test. If cancer is suspected, there is also a biopsy of prostate tissue. For healthy men over fifty, the American Cancer Society recommends an annual DRE and blood test.1 The blood test measures levels of a protein produced in the prostate gland called prostatespecific antigen (PSA). Approximately 50% of "older men" now undergo routine PSA screenings. [ABSTRACT FROM AUTHOR]

The subject of smoking has blackened innumerable pages since the first reports of adverse health effects appeared fifty-some years ago. Public health campaigns, scientific research, the anti-tobacco lobby, and cigarette company trials have all contributed to bring about such a change in the public conscience as would have been unimaginable half a century ago. In 1965, almost half of all American adults were cigarette smokers. By 1985, the proportion of adult smokers had fallen to about 30%. In the late nineties, California introduced anti-smoking legislation, and many other places followed suit. In 2003, New York City banned smoking in bars and restaurants. But according to the CDC, more than 20% of the US adult population still smokes. What exactly are the health risks that these 47 million Americans tacitly accept by continuing to smoke? This is the key question. [ABSTRACT FROM AUTHOR]

Coronary heart disease (CHD) is the leading cause of death in industrialized countries throughout the world, and is by far the number one killer in the United States. Over 70 million Americans have some form of cardiovascular disease, and approximately one million of them die from it each year. Heart disease accounted for nearly 40% of all deaths in the United States at the turn of the 21st century. These are frightening statistics. So it is not surprising that CHD has attracted intense interest in the public health community for decades. With "baby boomers" aging and more individuals being affected by CHD, this interest will continue to grow. It's increasingly important that we understand CHD so we can reduce or eliminate those conditions responsible for this disease. Unfortunately, in spite of years of research and costly clinical and epidemiological studies targeting CHD, scientists and physicians have not been able to discover any definitive cause and effect relationships. The causes of CHD and of its precursor, atherosclerosis - in which fatty deposits, cholesterol, cellular waste products, calcium, and other substances build up on the lining of arteries - are still unknown. So judgments about why CHD occurs and how to control it are based on the presence or absence of risk factors. There are many risk factors which have been associated with atherosclerosis and CHD. At present, the list includes: cigarette smoking, elevated blood pressure, elevated cholesterol, low serum HDL cholesterol, diabetes, advancing age, obesity, abdominal obesity, physical inactivity, family history of premature coronary heart disease, ethnic characteristics, psychosocial factors, elevated serum triglycerides, small LDL particles, elevated serum homocysteine, elevated serum lipoprotein(a), elevated fibrinogen, elevated inflammatory markers… and the list of suspect factors goes on. Yet most of these risk factors individually have almost no value in predicting whether CHD or atherosclerosis will occur. [ABSTRACT FROM AUTHOR]

The American Cancer Society estimates that over 107,000 people were newly diagnosed with colon cancer in 2002. More than 56,000 people died of this cancer that same year.2 Colorectal cancer develops in the rectum or the colon, and is one of the leading cancer killers in the US. Both men and women are at risk. Ninety-three percent of cases occur in people age 50 or older. The risk of developing colorectal cancer increases with age. There are screening programs for colorectal cancer. The primary purpose of a screening test is to identify disease in people who don't have symptoms yet. Catching the problem at an early stage may allow treatment to prevent the full-blown disease, or at least to reduce its severity. The occurrence of the disease and the mortality from the disease must justify the effort and the expense of screening. In the case of colorectal cancer, these criteria have been met. The screening test looks for cancerous cells in the colon. The key question: is there evidence that colorectal cancer screening confers a survival benefit due to the early detection of colorectal cancer? In other words, what is the absolute risk reduction (ARR) for people who have had the screening test compared to people who have not? [ABSTRACT FROM AUTHOR]

Statins - LescolTM, LipitorTM, MevacorTM, PravacolTM, and ZocorTM - are the most widely used prescription drugs in the world. Over 20 million people worldwide take statins, and the resulting annual sales exceeded 16 billion dollars in 2001.2 Why are they so popular? People take statins to lower their cholesterol. Indeed, these drugs can reduce blood serum cholesterol levels by 30 to 40% or more. As described in the previous chapter, experts have found that the incidence of coronary heart disease (CHD) is essentially the same for people with elevated and normal blood serum cholesterol levels. The Cholesterol Risk Characterization Theaters (RCTs) shown in Chap. 8 suggest that the level of benefit from reducing cholesterol levels may not support the contention that cholesterol is a primary risk factor for CHD. Yet many of the people who take statins to lower their cholesterol do so in the hopes of reducing their risk of heart disease. Two key questions arise. Do individuals taking statins have a lower incidence of CHD when compared to individuals not taking these drugs? If so, are the benefits due to lowering blood serum cholesterol levels, or are they due to something else? [ABSTRACT FROM AUTHOR]

A health benefit is defined as the chance of improvement or positive outcome from a medical screening test or drug intervention. A health risk is the chance of harm from a medical treatment program or exposure to an environmental contaminant. All health benefits and risks involve chance or probability, because we can never know the future with complete certainty. Previous chapters have discussed how the estimates of the probability of a benefit or adverse outcome are made with more or less confidence. When there is a clear cause and effect relationship, such as in the case of HIV and AIDS, the confidence level is high. When a cause and effect relationship has not been identified, there is a lower level of confidence in predictions about the possible benefits or adverse effects to human health. [ABSTRACT FROM AUTHOR]

VioxxTM (rofecoxib) was one of the drugs approved by the Food and Drug Administration for short-term treatment of acute pain and long-term treatment of rheumatoid arthritis and osteoarthritis. It seems, however, that these benefits came at a cost: higher risk of heart attack and stroke. A recent study estimated that VioxxTM could have caused between 88,000 and 140,000 extra cases since its launch in 1999. Another study suggested that millions of people may have been unnecessarily exposed to the risk of heart attacks by taking VioxxTM and other medicines classified as nonsteroidal anti-inflammatory drugs (NSAIDs). It appears that information on the benefits and risks of taking these drugs has not been clearly presented to the public. Problems with risk framing may be responsible for the less-than-helpful characterization of risks associated with these NSAIDs. Therefore, physicians, the FDA and other federal regulators, the media, and the public probably have an incomplete understanding of the risks and benefits. The results of scientific studies provide good reason to assume there is an increased risk from cardiovascular events associated with taking VioxxTM. However, some patients seem unable to get relief with other drugs. Patients would, in all probability, benefit from an awareness of the specific risks and benefits associated with VioxxTM. [ABSTRACT FROM AUTHOR]

The events and risk assessment results discussed and presented in this chapter are accurate in terms of location, organizations involved, analysis of data, and interpretation of results. The authors invented the reporter and EPA official as a more engrossing way to present this information. [ABSTRACT FROM AUTHOR]

The general public is faced with a difficult and perhaps even insurmountable task: find and decipher objective information about health benefits and risks in order to make the right decisions about medical and environmental issues. Why is it so hard? Because, although there are plenty of articles and reports advising people to learn about uncertainty and the differences between absolute and relative risks, there's virtually nothing giving examples of exactly what should be done. The complex technical information is not translated into a straightforward, simple format that presents the uncertainty, risks, and benefits associated with screening tests, environmental risk assessments, and drugs for treating chronic ailments. The public is left to sift through contradictory information to find the most "meaningful" health benefit and risk statistics presented to them by experts. [ABSTRACT FROM AUTHOR]

The doctor explained that when there are two events, with the first consistently resulting in the second, scientists recognize them as cause and effect. The cause makes something happen. The effect is what happens. She gave Alice some medical examples:HIV is the cause, AIDS is the effect.The polio virus is the cause, poliomyelitis is the effect.A type of parasite called a plasmodium is the cause, malaria is the effect. In these instances, medical science has demonstrated with a high degree of certainty that a disease will occur if the agent known to be causative is present. By definition of cause and effect, the disease-causing agent must always be present if the effect is to occur. When a specific cause is consist- ently linked with a specific effect, there's little uncertainty about the diagnosis, and intervention is almost always warranted. [ABSTRACT FROM AUTHOR]

We noticed the lump on the back of my seven-year-old son's calf, just below the knee, when he was lying on the living room rug watching television. At first we thought it was an insect bite or sting, but we couldn't find a red or elevated spot. Jason Rifkin was not in any pain and had absolutely no interest in my wife's suggestion that we take him to urgent care at the hospital "just to be sure." The doctor who examined him wrote a referral to an orthopedic surgeon and suggested we make an appointment ASAP. At that point we became concerned, though we tried to maintain our composure in front of our son. It was Monday and the appointment wasn't until Thursday. I spent the next couple of days reviewing all the medical information I could find that seemed to relate to Jason's lump. What struck me, more than anything else, was the uncertainty associated with diagnosing this condition. The range of possibilities was vast. It could have been a cyst (one of four or more types), a benign adipose tumor, a fatty deposit, a reaction to an infection - or it could have been a cancerous growth. [ABSTRACT FROM AUTHOR]