Introduction to Preventive Medicine CHAPTER OUTLINE I. BASIC CONCEPTS 1. BASIC CONCEPTS 173 A. Health Defined 173 Western medical education and practice have traditionally B. Health as Successful Adaptation 173 ocused on the diagnosis and treatment of disease. Diagnos- C. Health as Satisfactory Functioning 174 ing and t ting disease will always be important, but equal . MEASURES OF HEALTH STATUS 174 importance should be placed on the preservation and enhancement of health. Although specialists undertake III. NATURAL HISTORY OF DISEASE 175 research, teaching, and clinical practice in the field of preven- IV. LEVELS OF PREVENTION 175 tive medicine, prevention is exclusive province A. Primary Prevention and Predisease Stage 175 of preventive medicine speci care of elderly 1. Health Promotion 176 persons is not limited to geriatricians. All clinicians should 2. Specific Protection 176 incorporate prevention into their practice B. Secondary Prevention and Latent Disease 176 C. Tertiary Prevention and Symptomatic Disease 176 A. Health Defined . Disability Limitation 176 2. Rehabilita ation I77 Health is more difficult to define erhaps the V. ECONOMICS OF PREVENTION 177 best known definition preamble to A. Demonstration of Benefits I77 the constitution of the B. Delay of Benefits 177 is a state of complete C. Accrual of Benefits I77 and not merely the D. Discounting 178 definition is strengt E.Priorities 178 ful concept of healt life, and that a d VI. PREVENTIVE MEDICINE TRAINING I7S VII. SUMMARY 179 REVIEW QUESTIONS, ANSWERS, AND EXPLANATIONS s con I and 2 of this text focus on ep ively to viron- ng level of demand 173
74 SECTION 3 Preventive Medicine and Public Health for adaptation to stressors in an individual is called the allo- expectancy on the basis of morbidity, the perceived qualit static load on an individual, and it may be an important of life, or both. Such indices also can be used to help guide contributor to many chronic diseases. linical practice and research. For example, they might show hat a country s emphasis on reducing mortality may not be C. Health as Satisfactory functioning producing equal results in improving the function or self- Often what matters most to people about their health is how perceived health of the country's population. When clini- ey function in their own environment. The inability to with a chronic disease, such as prostate cancer, this approach function at a satisfactory level brings many people to a physi- allows them to consider not only the treatment's impact cian more quickly than does the presence of discomfort mortality but also its side effects, such as incontinence and unctional problems might impinge on a persons ability to impotence. Describing survival estimates in terms of the see,to hear, or to be mobile As Dubos states, " Clearly, health quality of life communicates a fuller picture than survival and disease cannot be defined merely in terms of physiological, or mental attributes. Their real measure is the Life expectancy traditionally is defined as the average ability of the individual to function in a manner acceptable number of years of life remaining at a given age. The metric of which he is a part. breslow of quality-adjusted life years( QALY) incorporates both life describes health as "both(1)the current state of a human perceIved Impact rganism's equilibrium with the environment, often called illness, pain, and disability on the patients quality of life. health status, and (2 )the potential to maintain that balance. For example, a patient with hemiparesis from a stroke might However health is defined, it derives principally from be asked to estimate how many years of life with this dis- forces other than medical care. Appropriate nutrition, ade ability would have a value that equals to I year of life with quate shelter, a nonthreatening environment, support good health(healthy years). If the answer were that 2 limited relationships, and a prudent lifestyle contribute far more to years is equivalent to 1 healthy year, I year of life after a health and well-being than does the medical care system stroke might be given a quality weight of 0.5. If 3 limited Nevertheless, medicine contributes to health not onl ears were equivalent to I healthy year, each limited year through patient care, but also indirectly by developing and would contribute 0 33 year to the QALY. Someone who mu disseminating knowledge about health promotion, disease live in a nursing home and is unable to speak might consider life under those conditions to be as bad as, or worse than no life at all. In this the weighting factor would be 0.0 fe II. MEASURES OF HEALTH STATuS lealthy life expectancy is a less subjective measure that attempts to combine mortality and morbidity into one Measures of health status can be based on mortality, on the index. The index reflects the number of years of life remain pact of a particular disease on quality of life, and on the ing that are expected to be free of serious disease. The onset y to function. Historically, measures of health status of a serious disease with permanent sequelae(e. g, peripheral have been based primarily on mortality data(see Chapter 2). vascular disease leading to amputation of a leg)reduces the Researchers assumed that a low age-adjusted death rate and healthy life expectancy index as much as if the person who high life expectancy reflected good health in a population. has the sequela had died from the disease Another way to account for premature mortality in different Other indices combine several measures of health status age groups is the measure of years of potential life lost The general well-being adjustment scale is an index that YPLL). This measure is used mainly in the field of injury measures"anxiety, depression, general health, positive well prevention In YPLL, deaths will be weighted depending on being, self-control, and vitality. Another index is called the how many years a person might have lived if he or she had life expectancy free of disability, which defines itself. The not died prematurely. This measure gives more weight to U.S. Centers for Disease Control and Prevention(CDC) developed an index called the health-related quality of life Using measures of mortality alone has seemed inadequate based on data from the Behavioral risk Factor Surveillance an increasing proportion of the population in developed System(BRFSS). Using the BRFSS data, CDC investigators and disabling illnesses. An appropriate societal goal is for good to excellent. Also, the e average number of good health people to age in a healthy manner, with minimal disability days(the number of days free of physical and mental health until shortly before death. Therefore, health care investiga problems during the 30-day period preceding the interview) tors and practitioners now show increased emphasis on was 25 days in the adults surveyed improving and measuring the health-related quality of life. Several scales measure the ability of patients to perform Measures of the quality of life are subjective and thus more their daily activities. These functional indices measure activi hallenging to develop than measures of mortality. However, ties that directly contribute to most people's quality of life, efforts to improve the methods for measuring quality of life without asking patients to estimate the quality of life com are ongoing. ared to how they would feel if they were in perfect health An example of such a measure is a health status index. uch functional indices include Katz's activity of daily living A health index summarizes a person's health as a single (ADL) index and Lawton- Brody's instrumental activities of score,whereas a health profile seeks to rate a persons health daily living(IADL)scale. These scales have been used exten on several separate dimensions. Most health indices and sively in the geriatric population and for developmentally profiles require that each subject complete some form of challenged adults. The ADL index measures a peng( eed, and ns abilit questionnaire. Many hea th status indices seek to adjust life independently to bathe, dress, toilet, transfer
CHAPTER 4 Introduction to Preventive medicine control their bladder and bowels. Items in the IADL scale may accelerate the development of atherosclerosis, and it include shopping, housekeeping, handling finances, and may lead to increased myocardial oxygen demand, precipi taking responsibility in administering medications. Other tating infarction earlier than it otherwise might have occurred scales are used for particular diseases, such as the Karnofsky and making recovery more difficult. In some cultures, coro index for cancer patients, and the Barthel index for stroke nary artery disease is all but unknown, despite considerable patients. genetic overlap with cultures in which it is hyperendemic, hat genot of many factors influe ing the development of atherosclerosis. I. NATURAL HISTORY OF DISEASE After a myocardial infarction occurs, some patients di some recover completely, and others recover but have serious The natural history of disease can be seen as having three sequelae that limit their function. Treatment may improve stages: the predisease stage, the latent(asymptomatic)disease the outcome so that death or serious sequelae are avoided tage, and the symptomatic disease stage. Before a disease Intensive changes in diet, exercise, and behavior(e.g,cessa- tion of smoking) may stop the progression of atheromas or disease stage-the individual can be seen as possessing even partially reverse them arious factors that promote or resist disease These factors include genetic makeup, demographic characteristics(espe cially age), environmental exposures, nutritional history, IV, LEVELS OF PREVENTION social environment, immunologic capability, and behavioral patterns. A useful concept of prevention that was developed or at least bularized in the classic account by Leavell and Clarkhas diseases)or quickly (as with most infectious diseases). If the all the activities of clinicians and other health professional disease-producing process is underway, but no symptoms of have the goal of prevention. There are three levels of preven- disease have become apparent, the disease is said to be in the tion(Table 14-1). The factor to be prevented depends on the latent(hidden)stage. If the underlying disease is detectable stage of health or disease in the individual receiving preven by a reasonably safe and cost-effective means during this tive care tage, screening may be feasible. In this sense, the latent stage Primary prevention keeps the disease process from may represent a window of opportunity during which becoming established by eliminating causes of disease or by detection followed by treatment provides a better chance of increasing resistance to disease(see Chapter 15). Secondary ure or at least effective treatment, to prevent or forestall prevention interrupts the disease process before it becomes mptomatic disease. For some diseases, such as pancreatic symptomatic( Chapter 16). Tertiary prevention limits the cancer, there is no window of opportunity because safe and physical and social consequences of symptomatic disease effective screening methods are unavailable. For other dis (Chapter 17). Which prevention level is applicable al eases, such as rapidly progressive conditions, the window of depends on which disease is the focus or what conditions are opportunity may be too short to be useful for screening considered diseases. For example, controlling cholesterol programs. Screening programs are detailed in Chapter 16 levels in an otherwise healthy person can be primary prever (see Table 16-2 for screening program criteria tion for coronary artery disease(e.g, if the physician treats When the disease is advanced enough to produce clinical incidental high cholesterol before the patient has any signs or manifestations, it is in the symptomatic stage. Even symptoms of coronary artery disease). However, if the phys stage, the earlier the condition is diagnosed and trea cian considers hypercholesterolemia itself to be a disease more likely the treatment will delay death or serious treating cholesterol levels could be considered secondary pre- cations,or at least provide the opportunity for vention(i.e, treating cholesterol level before fatty atheroma rehabilitation tous deposits form). For hypertension, efforts to lower blood The natural history of a disease is its normal course pressure can be considered primary, secondary, or tertiary the absence of intervention. The central question for studies prevention; primary prevention might be measures to treat of prevention(field trials) and studies of treatment(clinical prehypertension, secondary prevention if the physician is trials)is whether the use of a particular preventive or treat- treating a hypertensive patient, or tertiary prevention for a ment measure would change the natural history of disease patient with symptoms from a hypertensive crisis. in a favorable direction, by delaying or preventing clinical manifestations, complications, or deaths, Many interven tions do not prevent the progression of disease, but instead A. Primary Prevention and Predisease Stage slow the progression so that the disease occurs later in life Most noninfectious diseases can be seen as having an early than it would have occurred if there had been no stage, during which the causal factors start to produce physi Intervention ologic abnormalities. During the predisease stage, athero In the case of myocardial infarction, risk factors include sclerosis may begin with elevated blood levels of the"bad male gender, a history of myocardial infarction, ele- low-densit protein(LDL) cholesterol and may be vated serum lipid levels, a high-fat diet, cigarette smoking, accompanied by low levels of the"good"or scavenger higl sedentary lifestyle, other illnesses (e. g, diabetes mellitus, density lipoprotein(HDL) cholesterol. The goal of a health hypertension), and advancing age. The speed with which intervention at this time is to modify risk factors in a favor coronary atherosclerosis develops in an individual would be able direction. Lifestyle-modifying activities, such as chang modified not only by the diet, but also by the pattern of ng to a diet low in saturated and trans fats, pursuing a physical activity over the course of a lifetime. Hypertension consistent program of aerobic exercise, and ceasing to smoke
SECTION 3 Preventive medicine and public health Table 14- Modifed Version of Leavell's Levels of Prevention Stage of Disease and Care Level of prevention Appropriate Response Predisease sta No known risk factors Imary prevention urage healthy changes in lifestyle, Latent Disease Secondary pre for individuals in medical Initial care Tertiary prevention Subsequent Tertiary prevention Rehabilitation (i.e,, identify and teach methods to reduce physical and avell HR. Clark EG: in his comnunity ed 3, New York, 1965, McGraw-Hill. ell originally categorized disability limitation condary prevention, it has become customary in Europe and the United States to classify disability tiary prevention because it involves the man symptomatic disease. cigarettes, are considered to be methods of primary preven- at a specific disease or type of injury. Examples include on because they are aimed at keeping the pathologic process immunization against poliomyelitis; pharmacologic treat and disease from occurring ment of hypertension to prevent subsequent end-organ damage; use of ear-protecting devices in loud working envi- Health Promotion ronments, such as around jet airplanes; and use of seat belts air bags, and helmets to prevent bodily injuries in automo Health-promoting activities usually contribute to the bile and motorcycle crashes. Some measures provide specific primary (and often secondary and tertiary) prevention of a protection while contributing to the more general goal of variety of diseases and enhance a positive feeling of health health promotion. Fluoridation of water supplies not only and vigor. These activities consist of nonmedical efforts, helps to prevent dental caries but also is a nutritional inter uch as changes in lifestyle, nutrition, and the environment. vention that promotes stronger bone Such activities may require structural improvements in society to enable more people to participate in them. These improvements require societal changes that make healthy B. Secondary Prevention and Latent Disease choices easier. Dietary modification may be difficult unless Sooner or later, depending on the individual, a disease process variety of healthy foods are available in local stores at a such as coronary artery atherosclerosis progresses sufficiently reasonable cost. Exercise is more difficult if bicycling or to become detectable by medical tests, such as cardiac stress jogging is a risky activity because of automobile traffic or test, although the individual is still asymptomatic. This may ocial violence. Even more basic to health promotion is the be thought of as the latent(hidden) stage of disease assurance of the basic necessities of life, including freedom For many infectious and noninfectious diseases, screening from poverty, environmental pollution, and violence. tests allow the detection of latent disease in individuals con- Health promotion applies to noninfectious diseases and sidered to be at high risk. Presymptomatic dia through to infectious diseases. Infectious diseases are reduced in fre screening programs, along with subsequent treatment when quency and seriousness where the water is clean, where needed, is referred to as secondary prevention because it is the liquid and solid wastes are disposed of in a sanitary manner, secondary line of defense against disease. Although screening and where animal vectors of disease are controlled. Crowd programs do not prevent the causes from initiating the ing promotes the spread of infectious diseases, whereas ade- disease process, they may allow diagnosis at an earlier stage quate housing and working environments tend to minimiz of disease, when treatment is more effective the spread of disease. In the barracks of soldiers, for exampl even a technique as simple as requiring soldiers in adjacent C. Tertiary Prevention and Symptomatic Disease ind the foot of the bed can reduce the spread of respiratory When disease has become symptomatic and medical assis diseases, because it doubles the distance between the soldiers' tance is sought, the goal of the clinician is to provide tertiary upper respiratory tracts during sleeping time. revention in the form of disability lin I patients with early symptomatic disease, or rehabilitation for patients 2. Specific Protection with late symptomatic disease(see Table 14-1) Usually, general health-promoting changes in environment, nutrition and behavior not fully effective. Ther Disability limitation becomes necessary to employ specific protection(see Table Disability limitation describes medical and surgical 14-1). This form of primary prevention is targeted sures aimed at correcting the anatomic and physiol
CHAPTER 4 Introduction to Preventive medicine components of disease in symptomatic patients. Most care Much depends on the frequency of the disease in the popula provided by clinicians meets this description. Disability lim tion and the characteristics of the preventive measures tation can be considered prevention because its goal is to halt Tables of the most valuable clinical services are available. slow the disease process and prevent or limit complica- The Partnership for Prevention has been founded as a tions, impairment, and disability. An example is the surgical national not-for-profit health organization dedicated to emoval of a tumor, which may prevent the spread of disease evidence-based prevention grounded in"value. locally or by metastasis to other sites. Discussions about a There are particular challenges to demonstrating bene- patient's disease also may provide an opportunity("teach- fits for preventive measures and achieving meaningful ble moment") to convince the patient to begin health pro oPtion motion techniques designed to delay disease progression (e.g, to begin exercising and improving the diet and to stop A. Demonstration of Benefts smoking after a myocardial infarction Scientific proof of benefits may be difficult because it is often 2. Rehabilitation impractical or unethical to undertake randomized trials of harm using people as subjects. For example, it is impossible form of preve ny are surprised to see rehabilitation designated to assign people randomly to smoking and nonsmoking ention, the label is correctly applied. Rehabi groups. Apart from some research done on animal mode mitigate the effects of disease and prevent some investigators are limited to observational studies, which of the social and functional disability that would otherwise usually are not as convincing as experiments. Life is filled Ls; eay be taught self-care in activities of daily living operate together to produce the levels of health ooscrrd o person to avoid the adverse sequelae associated with pre different subpopulations, making it impossible to infer what longed inactivity, such as increasing muscle weakness that roportion of the improvement observed over time is caused night develop without therapy. Rehabilitation of a stroke by a particular preventive measure. If there is a reduction in patient begins with early and frequent mobilization of all the incidence of lung cancer, it is difficult to infer what pro joints during the period of maximum paralysis. This permits portion is caused by smoking reduction programs and what easier recovery of limb use by preventing the development proportion by the elimination of smoking in workplaces and of stiff joints and flexion contractures. Next, physical therapy public areas, the increase in public awareness of (and action helps stroke patients to strengthen remaining muscle func- against) the presence of radon in homes, and other factors tion and to use this remaining function to maximum effect as yet poorly understood. Lastly, clinical research is expen in performing ADLs. Occupational and speech therapy may sive. A majority of research on treatment and diagnosis enable such patients to gain skills and perform some type of modalities is sponsored by pharmaceutical companies. The gainful employment, preventing complete economic depen- money spent by them to support clinical research is vastly dence on others. It is legitimate, therefore, to view rehabilita- greater than the research dollars spent on prevention. There tion as a form of prevention. fore, some of the lack of data might result from the lack of V. ECONOMICS OF PREVENTION B. Delay of Benefits In an era of cost consciousness, there are increasing With most preventive programs, there is a long delay between demands that health promotion and disease prevention b he time the preventive measures are instituted and the proven economically worthwhile. Furthermore, many people time that positive health changes become discernible itical arena promote prevention as a means of Because the latent period(incubation period) for lung controlling rising health care costs. This argument is based cancer caused by on the belief that prevention is always cost-saving. One way benefits resulting from investments made now in smoking to examine that claim is to look at the cost -effectiveness of tified until many yea various preventive measures and compare them to the cost- have passed. There are similar delays between the time of effectiveness of treatment for existing conditions. smoking cessation and the demonstration of effect for othe As outlined in Chapter 6, cost-benefit analysis compares moking-related pulmonary problems, such as obstructive the costs of an intervention to its health benefits. In order to pulmonary disease. Most chronic diseases can be shown to compare different interventions, it becomes necessary to have long latent periods between when the causes start and express the health benefits of different interventions with the the disease appear ame metric, called cost-effectiveness analysis(Box 14-1) Examples for such metrics are mortality, disease, and costs, C. Accrual of Benefits r their inverse: longevity, disease-free time, and savings. A subtype of cost-effectiveness analysis is cost-utility analysis, Even if a given program could be shown to produce mear which has the outcome of the cost/quality-adjusted life year, ingful economic benefit, it is necessary to know to whom the also called the cost-effectiveness ratio( CER). A recent com benefits would accrue. For example, a financially stressed parison of the CER of various preventive measures with health insurance plan or health maintenance organization treatments for existing conditions found that both prey might cover a preventive measure if the financial benefit tive and curative measures span the cost-effectiveness spec- were fairly certain to be as great as or greater than the cost trum; both can be cost-saving, favorable, or unfavorable 6 of providing that benefit, but only if most or all of the
SECTION 3 Preventive medicine and public health Box 14-1 Cost-Beneft and Cost-Effectiveness Analysis Cost-benefit analysis measures the costs and the benefits of a pro- various forms and complications of hepatitis, Bloom et al. calculated sed course of action in terms of the same units, usually monetar ry that the fourth strategy would have an undiscounted cost of about nits such as dollars. For example, a cost-benefit analysis of a po $367(or a discounted cost of $1205)per case of hepatitis B prevented yelitis im program would determine the and concluded this was the strategy with the lowest cost. (The CDC dollars to be spent toward vaccines, equipment, and personnel to now recommends immunizing all infants against hepatitis B immunize a particular population. It would determine the number of dollars that would be saved by not ha The chaotic situation in the United States regarding costs and charges r the izations, medical visits, and lost productivity that would occur if under different health insurance plans and in different hospital poliomyelitis were not prevented in that population makes it difficult to estimate medical care costs. The situation can be dealt with partly by performing a sensitivity analysis with Incorporating concepts such as the dollar value of life, suffering, an spreadsheets in which different costs per item are substituted to see the quality of life into such an analysis is difficult. Cost-benefit anal how they affect the total cost. sis is useful, however, if a particular budgetary entity (e. g, govern- In addition, the In addition, the concept of discounting, which is important in busi ment or business) is trying to determine whether the investment of ness and finance, must be used in medical cost-benefit and cost- resources in health would save money in the long run. It also is useful effectiveness analysis when the costs are incurred in the present but judgments about allocations between various sectors (e.g, health, the present value of delayed benefits (or increase in present costs) transportation, education)and to determine the sector in which to account for the time value of money. If the administrators of a investment would produce the greatest economic benefit prevention program spend $1000 now to save $1000 of expenses in Cost-effectiveness analysis provides a way of comparing different he future, they will take a net loss. This is because they will lose the proposed solutions in terms of the most appropriate measurement use of $1000 in the interim, and because with inflation the $1000 units. For example, ing hepatitis B cases prevented, deaths eventually saved will not be worth as much as the $1000 initially prevented, and life-years saved per 10,000 population, Bloom and spent. The use of discounting is an attempt to adjust for these forces leagues were able to compare the effectiveness of four different To discount a cost-benefit or cost-effectiveness analysis, the easiest strategies of dealing with the hepatitis B virus way is to increase the present costs by a yearly factor, which can be 1. No vaccination thought of as the interest that would have to be paid to borrow the money until the benefits occurred mple, if it costs 3. Screening followed by vaccination of unprotected individuals S1000 today to prevent a disease that would have occurred 20 years 4. A combination of the screening of pregnant women at delivery, in the future, the present cost can be multiplied by (1+r), where the vaccination of the newborns of women found to be antibody is the yearly interest rate for borrowing and n is the number of years positive during screening, and the routine vaccination of all until the benefit is realized. If the average yearly interest rate is 5% d children over 20 years, the formula becomes: (1+0.05)=(1.05)=2.653 When this is multiplied by the present cost of $1000, the result After estimating the numbers of persons involved in each step of $2653. The expected savings 20 yea the future from a S1000 each method and determining the costs of screening, purchasing, investment today would have to be greater than $2653 for the initial and administering the vaccine, and delivering medical care for investment to be a net(true)financial gain. From Bloom BS, Hillman AL, Fendrick AM, et al: A reappraisal of hepatitis B virus vaccination strategies using cost-effectiveness analysis. Ann Intern Med118:298-306,1993 financial benefit would accrue to the insurance plan in the D. Discounting near future. If plan members switch insurance plans fre quently, or if most of the financial benefit would go to the If a preventive effort is made now by a government body, the enrollees or a government rather than to the insurance plan, costs are present-day costs, but any financial savings may not the prevention program would be seen as only a financial be evident until many years from now. Even if the savings cost by the insurance plan re expected to accrue to the same budgetary unit that pro- The same principle is true for the even more financially vided the money for the preventive program, the delay strapped budgets of local, state, and federal governments. economic return means that the benefits are worth less to If the savings from prevention efforts would go directly that unit now. In the jargon of economists, the present value to individuals, rather than to a government budget, the of the benefits must be discounted(see Box 14-1), making elected representatives might not support the prevention it more difficult to show cost-effectiveness or a positive effort, even if the benefits clearly outweighed the costs benefit-cost ratio Elected representatives may want to show results before the next election campaign. Disease prevention may show results only over an extended time and may not lend itself to politi E. Priorities cal popularity. Even so, there seems to be growing political As the saying goes, the squeaky wheel gets the grease upport for at least the concept of prevention as a medical Current, urgent problems usually attract much more atten priority. tion and concern than future, subtle problems. Emergen
CHAPTER 4 Introduction to Preventive medicine care for of motor vehicle crashes is easy to justify, medicine. Typically, in these cases, the training time is short ts. Although prevention may be cost n a combined program than if residents did both programs effective, it may be difficult to justify using money to prevent sequentially. crises that have not yet occurred. The same dilemma applies The certification examination has two parts: a core exam- to essentially every phase of life. It is difficult to obtain ination and a subspecialty examination. The core examina- money for programs to prevent the loss of topsoil, prevent tion is the same for all three subspecialties and covers topics literacy, and prevent the decay of roads and bridges. Even such as epidemiology, biostatistics, environmental health on an individual level, many patients do not want to make health policy and financing, social science as applied to n their lives, such as eating a healthier diet, exercis blic health, and general clinical preventive medicine. and stopping smoking, because the risk of future prob- Further information for specialty training and board exami does not speak to them urgently in the present. As a nation is available on the Internet(see Websites) broader example, although the level-five hurricane cted for the U.S. Gulf Coast, inadequate were made by the individuals, cities, and states involved VIl. SUMMARY and by the federal government Preventive medicine seeks to enhance the lives of patients helping them promote their health and prevent specific d VI. PREVENTIVE MEDICINE TRAINING eases or diagnose them early Preventive medicine also tries to apply the concepts and techniques of health promotion Physicians desiring to become board-certified as and disease prevention to the organization and practice of in preventive medicine may seek postgraduate medicine(clinical preventive services). Health is an elusive concept but means more than the absence of disease; it is training by the Accreditation Council for graduat positive concept that includes the ability to adapt to stres ducation. Certification in preventive medicine must be in and the ability to function in society. The three levels of one of the following three subspecialty areas prevention define the various strategies available to practi- al preventive medicine and public health tioners to promote health and prevent disease, impairment, Occupational medicine and disability at various stages of the natural history of ■ Aerospace medicine disease. Primary prevention keeps a disease from becoming established by eliminating the causes of disease or increasing Occasionally, a physician becomes certified in two subsp resistance to disease. Secondary prevention interrupts the cialties(most often the first and second areas listed ). A few disease process by detecting and treating it in the presymp medical residency programs offer a combined residency in a tomatic stage. Tertiary prevention limits the physical impair clinical specialty (e.g., internal medicine) and preventive ment and social consequences from symptomatic disease. It medicine. a residency program in medical toxicology is gov- is not easy for prevention programs to compete for funds in erned by a tripartite board, with representatives from the a tight fiscal climate because of long delays before the ben American boards of preventive medicine, pediatrics, and efits of such investments are noted. Specialty training in emergency medicine. preventive medicine prepares investigators to demonstrate resic certification in preventive medicine requires 3 years of the cost-effectiveness and cost benefits of prevention ency. The first postgraduate year is called the clinical ith substantial patient care References esponsibility, usually in internal medicine, family practice r pediatrics, although other areas are acceptable if they 1. Dubos R: Man adapting, New Haven, Conn, 1965, Yale Univer provide sufficient patient responsibility. The internship may be done in any accredited, first-postgraduate-year residency 2. Selye H: Confusion and controversy in the stress field, J Hu offer the first postgraduate year, but most do not. The second Stress I:37-44,1975. 3. Selye H: The evolution of the stress concept, Am Sci 61: 692 postgraduate year is called the academic year and consists of 699,1973 ourse work to obtain the master of public health(MPH 4. McEwen BS, Stellar E: Stress and the individual. Arch Intern degree or its equivalent. The course work may be pursued in Medl53:20932101,1993 any accredited MPH program and need not be done in a 5. Dubos R: Mirage of health, New York, 1961, Doubleday formal preventive medicine residency program, although 6. Breslow L: From disease prevention to health promotion MAMA281:1030-1033,1999 there are some advantages in doing so. The third postgrad 7. Fries JF, Crapo LM: Vitality and aging, San Francisco, 1981, WH ate year is called the practicum year, and it must be com- Freer pleted in an accredited preventive medicine residency 8. Haywood KL, Garratt AM, Fitzpatrick R: Quality of life in older program. It consists of a year of supervised practice of the people: a structured review of generic self-assessed health ubspecialty in varied rotation sites, and it is tailored to fit an individual resident's needs. It typically includes clinical 9. McDowell I, Newell C: Measuring health: a guide to rating scale practice of the subspecialty: experience in program plan nd questionnaires, ed 2, New York, 1996, Oxford University ning, development, administration, and evaluatic ion; analysi and solution of problems (e.g., problems related to epidem 10. Last JM: A dictionary of epidemiology, ed 4, New York, 2001 Oxford University Press ics); research; and teaching. Some residency 11. Barendregt )), Be preventive medicine training combined with other special n indicator for change? J Epidemiol Community Health ties, such as internal medicine, pediatrics, or family 48:482-487,1994
SECTION 3 Preventive medicine and public health 12. Revicki DA, Allen H, Bungay K, et al: Responsiveness and cali- Fries JF Crapo LM: Vitality and aging, San Francisco, 1981, WH ration of the General Well Being Adjustment Scale in patients reeman. [The concept of prevention. J with hypertension, J Clin Epidemiol 47: 1333-1342, 1994 Muir Gray JA: Evidence-based healthcare: how to make health policy 3. US Centers for Disease Control and Prevention: Quality of life and management decisions, ed 2, Edinburgh, 2001, Churchill as a new public health measure: Behavioral Risk Factor Surveil lance System, MMWR 43: 375-380, 1994 Task Force on Principles for Economic Analysis of Health Care 14. US Centers for Disease Control and prevention: Health-related Technology: Economic analysis of health care technology: a lity of life measures: United States, 1993. MMWR 44: 195- report on principles, Ann Intern Med 123: 61-70, 1995. [Cost effectiveness and cost-benefit analysis. I 15. Leavell HR, Clark EG: Preventive medicine for the doctor in his d 3, New York, 1965, McGraw-Hi 16. Cohen JT, Neumann PJ, Weinstein MD: Does preventive care Websites ave money? Health economics and the presidential candidates http://www.acpm.org/?gmeMedstudents[amEricanCollegeof N Engl J Med358:661-663,2008 17. Maciosck MV, Coffield AB, Edwards NM, et al: Priorities http:/www.acpm.org/page=gmeHome[amerIcanCollegeof among effective clinical preventive services: results of a system Preventive Medicine: Graduate Training and Careers in Preven atic review and analysis. Am Prey Med 31: 52-61, 2006. tive Medicinel 18.PartnershipforPreventionhttpwww.prevent.orgaccessed http:/www.amsa.orglamsa/homepage/a Mittee/ underhttp://www.prevent.org/about-uS.aspx reventive Medicine. aspx [American Medica oca 19.http:/www.acpm.org/?gme_medsTudeNt n: Information on Preventive Medicine 20. Wild DMG, Tessier-Sherman B, D'Souza S, et al: Experiences with a combined residency i ttps: //research tufts-nemc org/ceard/default. aspx [Cost-Effectiveness Am J Prey med33:393-397,2008. Analysis Registry httpl/www.preventorgpaRtnershipforPrevention Dubos R: Mirage of health, New York, 1961, Doubleday. [The concept of prevention. J
