AbstractMeta‐analysis is a quantitative approach for systematically combining the results of previous research in order to arrive at conclusions about the body of research. The pressure for timely, evidence‐based decisions, and the explosion of the information in the scientific literature have resulted in an increased number of published meta‐analysis. Statistical methods are integral to each step of a meta‐analysis. In this chapter, we define meta‐analysis in the context of scientific synthesis, illustrate uses of Meta‐analysis in epidemiology and public health, describe the steps in a meta‐analysis, and illustrate some specific statistical issues, such as bias, and heterogeneity. We illustrate these steps with a case study of the effects of duration of estrogen on breast cancer risk and discuss statistical software and related internet resources. Statistical issues are critical to properly understanding and interpreting the results from meta‐analysis.

This supplement is the second of a series of periodic reports from a CDC initiative to monitor and report on the use of a set of selected clinical preventive services in the U.S. population in the context of recent national initiatives to improve access to and use of such services. Increasing the use of these services can result in substantial reductions in the burden of illness, death, and disability and lower treatment costs. This supplement focuses on services to improve the health of U.S. infants, children, and adolescents. The majority of clinical preventive services for infants, children, and adolescents are provided by the health-care sector. Public health agencies play important roles in increasing the use of these services by identifying and implementing policies that are effective in increasing use of the services and by collaborating with stakeholders to conduct programs to improve use. Recent health-reform initiatives, including efforts to increase the accessibility and affordability of preventive services, fund community prevention programs, and improve the use of health information technologies, offer opportunities to improve use of preventive services. This supplement, which follows a previous report on adult services, provides baseline information on the use of a set of selected clinical preventive services to improve the health of infants, children, and adolescents before implementation of these recent initiatives and discusses opportunities to increase the use of such services. This information can help public health practitioners, in collaboration with other stakeholders that have key roles in improving infant, child, and adolescent health (e.g., parents or guardians and their employers, health plans, health professionals, schools, child care facilities, community groups, and voluntary associations), understand the potential benefits of the recommended services, address the problem of underuse, and identify opportunities to apply effective strategies to improve use and foster accountability among stakeholders.

The US Centers for Disease Control and Prevention's Epidemic Intelligence Service (EIS) (US Department of Health and Human Services) is a 2-year training and service program that focuses on applied epidemiology and plays a critical role in developing practitioners experienced in public health surveillance. Epidemic Intelligence Service Officers receive didactic training and obtain practical experience in evaluation of surveillance systems. The service and learning process allows them to improve upon existing systems and at times to deploy new methods to monitor emerging or endemic diseases. Approximately 40 programs are patterned after the EIS program and make similar contributions to surveillance training and practice, as exemplified in this chapter by the European Programme for Intervention Epidemiology Training and related programs.

The origins of public health surveillance can be traced to Hippocrates, who is credited with observing, recording, and collecting facts and then analyzing them to inform reasonable courses of action. However, infectious disease surveillance, now a core function of public health, began as a reactive response to specific problems in community health. In this chapter, we trace infectious disease surveillance development throughout the world, including its expansion to encompass direct responsibility for control activities. Our review is focused around the purposes and uses of infectious disease surveillance systems. Purposes include assessing public health status, tracking conditions of public health importance, defining public health priorities, evaluating programs, and stimulating public health research. Uses include monitoring the natural history of conditions, detecting epidemics, detecting changes in etiologic agents, displaying patterns in distribution and spread of disease, documenting the effect of interventions and policies, evaluating control and prevention measures, documenting changes in medical practice, and aiding allocation of resources.

This supplement introduces a CDC initiative to monitor and report periodically on the use of a set of selected clinical preventive services in the U.S. adult population in the context of recent national initiatives to improve access to and use of such services. Increasing the use of these services has the potential to lead to substantial reductions in the burden of illness, death, and disability and to lower treatment costs. The majority of clinical preventive services are provided by the health-care sector, and public health agencies play important roles in helping to support increases in the use of these services (e.g., by identifying and implementing policies that are effective in increasing use of the services and by collaborating with stakeholders to conduct programs to improve use). Recent health reform initiatives, including efforts to increase the accessibility and affordability of preventive services, fund community prevention programs, and improve the use of health information technologies, offer opportunities to enhance use of preventive services. This supplement provides baseline information on a set of selected clinical preventive services before implementation of these recent reforms and discusses opportunities to increase the use of such services. This information can help public health practitioners collaborate with other stakeholders that have key roles to play in improving public health (e.g., employers, health plans, health professionals, and voluntary associations), understand the potential benefits of the recommended services, address the problem of underuse, and identify opportunities to apply effective strategies to improve use and foster accountability among stakeholders.

We appreciate the letter by Plochg et al. It makes the important point that our reflections on primary care and public health are focused on the United States, and that there is a very active movement in population health occurring internationally. The long-standing efforts of international colleagues in public health and primary care to integrate the two disciplines might offer lessons for us as well. However, the payment system, which we point to as a major barrier to previous US efforts at integration, is substantially different from our own in most international settings. Many countries enjoy a national health system that has the better potential for integration because there is one final governing authority for both public health and medical services. And, most notably, the funding for both comes from the same source, again not the case in the United States. As we pointed out, we are optimistic that the United States will now take a similar path as new forms of care delivery, such as accountable care organizations, require a focus on the health of the population they serve, whether it is a community or its enrollees. We would be well served to continue looking to international efforts at integration and alignment across the components of health care systems. It is likely that we can learn from the successes and mistakes of their efforts as we proceed in the United States.

In its landmark 1988 report, a committee of the Institute of Medicine highlighted assessment as one of the three core functions of public health along with policy development and assurance. The committee recommended that every public health agency regularly and systematically collect, assemble, analyze, and make available information on the health of the community, including statistics on health status, community health needs, and epidemiologic and other studies of health problems. Public health surveillance, often called the cornerstone of public health practice, is an essential element of the assessment function.

Multiple promising but unsustainable attempts have been made to maintain programs integrating primary care and public health since the middle of the last century. During the 1960s, social justice movements expanded access to primary care and began to integrate primary care with public health concepts both to meet community needs for medical care and to begin to address the social determinants of health. Two decades later, the managed care movement offered opportunities for integration of primary care and public health as many employers and government payers attempted to control healthcare costs and bring disease prevention strategies in line with payment mechanisms. Today, we again have the opportunity to align primary care with public health to improve the community's health. For scientific progress has greatly modified his ethical responsibility. His relation was formerly to his patient—at most to his patient's family; and it was almost altogether remedial . . . But the physician's function is fast becoming social and preventive rather than individual and curative. Upon him society relies to ascertain … the conditions that prevent disease and make positively for physical and moral well-being.—Abraham Flexner1Flexner A. Medical Education in the U.S. and Canada: A Report to the Carnegie Foundation for the Advancement of Teaching. Carnegie Foundation for the Advancement of Teaching, New York1910www.archive.org/details/medicaleducation00flexialaGoogle ScholarAlthough the American educator Abraham Flexner (1866–1959) made this observation more than a century ago in his assessment of the state of U.S. medical schools, the U.S. remains one of the few developed economies in which public health and medical care exist in isolation from each other. It was not always this way; physicians and their organizations once nurtured and developed the public health system. The divergence in the two disciplines, according to Starr,2Starr P. The Social Transformation of American Medicine: The Boundaries of Public Health. Basic Books, Inc., New York1982Google Scholar occurred at the turn of the 20th century, when the direct care of mothers and children by public health clinics prompted concerns that public health would begin to compete with physicians for the direct provision of medical care services. This divergence continued with medical specialization and was likely further enhanced by the Rockefeller Foundation's 1916 decision to create schools of public health that are separate from schools of medicine.3Welch WH, Rose W. Institute of Hygiene Annual Report, 1916, Appendix V. New York: Rockefeller Foundation.Google Scholar The ultimate consequences of this schism were the failure to attract physicians to public health, with a concomitant decline in the numbers of preventive medicine physicians, and the failure of most other physicians to understand or appreciate the population (or public health) perspective.4White K.L. Healing the Schism: Epidemiology, Medicine, and the Public's Health. Springer-Verlag Berlin, New York1991Crossref Google ScholarMultiple attempts have been made since the 1916 decision to reconnect primary care and public health; however, these innovations never expanded far beyond the site where they began, and even fewer were sustained. Today, new opportunities, needs, and tools offer us another opportunity to reintegrate public health and medicine—specifically primary care—in a way that improves population health outcomes and enhances quality of life in the U.S. By integration of primary care and public health we mean “the linkage of programs and activities to promote overall efficiency and effectiveness and achieve gains in population health.”5IOMPrimary Care and Public Health: Exploring Integration to Improve Population Health.in: The National Academies Press, Washington DC2012: 1Google Scholar However, if we are to seize the opportunity to bring primary care and public health together successfully, we must learn the lessons of past attempts.Historical ContextAfter the first half of the 20th century realized a dramatically increased life span resulting from potable water, infectious disease control, and increased access to medical care, the 1960s experienced new social justice movements and efforts to expand access to primary care, with a focus on working with communities to design and plan services that worked best for the underserved and uninsured. Experiments in community medicine and family medicine were derived from the community-oriented primary care (COPC) movement Kark and Cassel developed in South Africa, which integrated public health concepts with clinical medicine.6Kark S.L. Cassel J. The Pholela Health Centre: a progress report.Am J Public Health. 2002; 92: 1743-1747Crossref PubMed Scopus (10) Google Scholar These early efforts led to the development of community health centers, clinical epidemiology, and multidisciplinary teams. Physicians, nurses, health educators, and community lay health workers provided integrated medical and public health care to communities, often led by the community.6Kark S.L. Cassel J. The Pholela Health Centre: a progress report.Am J Public Health. 2002; 92: 1743-1747Crossref PubMed Scopus (10) Google Scholar The COPC movement emerged in the U.S. subsequently and contained many of these elements. In fact, those who Kark and his colleagues trained in these concepts provided leadership, in some measure, of this movement in the U.S. These experiments demonstrated how primary care and public health can intertwine to meet an obvious need for medical care and address the socioecologic determinants of health problems in underserved communities.Community Health CentersBoth Geiger7Geiger H.J. The neighborhood health center Education of the faculty in preventive medicine.Arch Environ Health. 1967; 14: 912-916Crossref PubMed Scopus (18) Google Scholar and Gibson8Gibson Jr, C.D. The neighborhood health center: the primary unit of health care.Am J Public Health Nations Health. 1968; 58: 1188-1191Crossref PubMed Scopus (16) Google Scholar—the initial advocates of community health centers and of ensuring access to primary care services—came from a medical perspective, albeit one infused with public health notions of concern for the denominator, a focus on the patients enrolled in the community health center's panel, and the community the center served. Of note, these leaders in the community health center movement, although trained in both medicine and public health, operated from a medical school environment. They maintained primary appointments in schools of medicine and not in schools of public health, and primarily medical schools supported these efforts. Rarely were schools of public health engaged in leading the development of community health centers, in other programs focused on direct service to the poor and uninsured, or on broader concerns of the communities that surrounded those community health centers. Few if any schools of public health applied for support for these community health centers; the majority of applicants were medical schools because academic medical centers often believed the needs of the residents in surrounding communities were not being addressed in those medical centers.Governmental health entities (e.g., city hospital and health department units) did get involved in this effort. This particularly applied to large urban entities that included hospitals, local primary care clinics, and public health clinics under one organization's structure that had the capacity to pursue the development of such community health centers. One of the first community health centers was centered at a local health department that collaborated with a university medical center, but public health leaders, both academic and governmental, regarded this as a provision of medical care and not the purview of public health. In certain cases, the entry of public health into community clinic sponsorship revived the concern Starr laid out: that the health department was in the business of competing with the private practice of medicine, a philosophical and financial concern for medicine.2Starr P. The Social Transformation of American Medicine: The Boundaries of Public Health. Basic Books, Inc., New York1982Google Scholar Meanwhile, health departments were concerned that the provision of illness services might detract from the population services only the health department could provide, whereas others could serve a patient care role. The schism remained.Although these initiatives focused primarily on the uninsured, the broader problems of financial access to medical care for older and poor people resulted in the creation and growth of Medicare and Medicaid. Those two major social insurance programs greatly expanded access to care for the underserved. However, the programs' incentives were to treat rather than prevent illness, and, consequently, they focused less on primary and preventive services than on procedures and hospital care. Notably, the nature of this initial foray into social insurance set the tone for the continued estrangement of medical and public health through the financial incentives that were provided. Payment was made for procedures and major illness more than for primary care or community interventions that address the underlying etiologies of illness, much less payment for quality of care or the health of a population. In fact, in the initial legislation, Medicare was precluded specifically from paying for clinical preventive services.The interest in primary care grew in parallel with or was the result of the community health center movement. The specialty of family medicine developed and gained popularity in the U.S., achieving American Board of Medical Specialties specialty recognition in 1969. A focus on individuals, families, and communities and on treatment, prevention and community medicine was part of the initial scope of the new discipline, reflecting the social movement that supported its establishment.9Willard W. Meeting the Challenge of Family Practice: The Report of the Ad Hoc Committee on Education for Family Practice of the Council on Medical Education. Council on Medical Education, American Medical Association, Chicago1966Google ScholarThese movements—community health centers, primary care (especially family medicine), and community medicine—were infused and supported by the larger COPC movement in the U.S. in the 1970s and 1980s, which brought together the notions of primary care and the practice of epidemiology to examine the health of the population of enrollees in a particular practice (e.g., that of the community health center) and to design, implement, and evaluate efforts to address broader community health problems.10Nutting P.A. Wood M. Conner E.M. Community-oriented primary care in the U.S.: a status report.JAMA. 1985; 253: 1763-1766Crossref PubMed Scopus (37) Google Scholar Disciplines of public health, particularly epidemiology, health behavior, and health education, were leveraged to the benefit of both the individual patient and the community. However, the movement soon faltered as attention shifted to growing national concerns about escalating costs. Community health centers came under pressure to increase their self-support through increased volumes of medical services at the expense of other direct nonmedical roles for the health of the population they served, but financial incentives to continue these efforts were lacking.11Stephens G.G. Family Practice in the 1980s: A Second Decade of Essays. Society of Teachers of Family Medicine Foundation, Kansas City MO1990Google Scholar These pressures led to constraints on innovations designed to bridge the schism and went so far as to require community health centers to deliver clinical services only. Philosophical and ideological concerns existed about the expanded role of community health centers, and support for efforts other than the provision of direct patient service declined. Once again, progress in population health was suppressed and gains rarely were sustained.This development included certain ironies. One was the key role of medical schools. Departments of preventive, social, and community medicine in medical schools led the community health center movement. The initial involvement of schools of public health faculty was limited despite the role that epidemiology and the emerging sciences of medical care organization and administration could play in this new effort. Some suggested that public health knowledge and education should not be focused solely in schools of public health but also contained in schools of medicine because the public health sciences were as integral to medicine as were the basic sciences of anatomy and physiology.12Bulger R. The medical school's mission and the population's health: medical education in Canada, the United Kingdom, the U.S., and Australia.JAMA. 1992; 268: 1077-1078Crossref Google ScholarIn a similar way, these same medical school departments became home to the growing family medicine movement. Community, social, and preventive medicine departments were subsumed by that movement and morphed into departments of community and family medicine. However, as family medicine turned its attention to establishing legitimacy with traditional medical specialties12Bulger R. The medical school's mission and the population's health: medical education in Canada, the United Kingdom, the U.S., and Australia.JAMA. 1992; 268: 1077-1078Crossref Google Scholar and as medical schools placed increasing emphasis on practice income, the community medicine portion of these departments withered and, in certain cases, disappeared.By 1982, when Deuschle13Deuschle K.W. Community-oriented primary care: lessons learned in three decades.J Community Health. 1982; 8: 13-22Crossref PubMed Scopus (25) Google Scholar reviewed the problems of maintaining primary care and public health innovation in COPC and community health centers that he was responsible for founding, the dominance—philosophically and financially—of the traditional medical practice and discomfort with organizational innovations clearly had become major obstacles to maintaining that effort.Managed CareThe 1980s and 1990s experienced another opportunity for the integration of medicine, primary care, and public health as employers and government payers turned to managed care health plans to attempt to control escalating health costs. One of the promises of managed care was to realize cost savings through a focus on prevention and attempts to bring more disease prevention strategies in line with payment mechanisms.14Scutchfield F.D. Harris J.R. Koplan J.P. Lawrence D.M. Gordon R.L. Violante T. Managed care and public health.J Public Health Manag Pract. 1998; 4: 1-11PubMed Google Scholar The emphasis on value, quality, and cost and the improvement in population health, measured by the health status of subscribers, were regarded by many as the sine qua non of effective managed care organizations. Unfortunately, the management and implementation of certain forms of managed care became concerned primarily with cost. The phrase “We are only saving Medicare money with prevention” was heard in the discussions of many managed care organizations. To echo Stephens's comments, efficiency trumped equity.11Stephens G.G. Family Practice in the 1980s: A Second Decade of Essays. Society of Teachers of Family Medicine Foundation, Kansas City MO1990Google Scholar On the positive side, settings in which the promise of managed care continues still exist—notably the Kaiser Foundation Health Plans in California—and they appear to be effective in achieving those goals.Medicine Public Health InitiativeA more recent effort to heal the schism between medicine and public health involved the American Medical Association and the American Public Health Association and began in 1994 amid calls for coordinated actions on shared concerns.15Beitsch L.M. Brooks R.G. Glasser J.H. Coble Y.D. The medicine and public health initiative ten years later.Am J Prev Med. 2005; 29: 149-153Abstract Full Text Full Text PDF PubMed Scopus (25) Google Scholar This initiative began with an agenda that called for the following: 1engaging the community;2changing the educational processes of both medicine and public health;3joining research efforts;4devising a shared view of health and illness;5working together to provide health services;6developing health assessment measures; and7translating initiatives into action.Despite continued concern, for example, an American Medical Association presidential address in 2007 stated that leadership turnover and the changing political agenda of the two organizations and their members had resulted in a lack of pursuit of this effort to bring medicine and public health together.16Davis R.M. Marriage counseling for medicine and public health: strengthening the bond between these two health sectors.Am J Prev Med. 2005; 29: 154-157Abstract Full Text Full Text PDF PubMed Scopus (9) Google Scholar Against that backdrop resides the current efforts calling for the integration of primary medical care and public health.Today, the need and opportunities have never been greater. In 1960, the Congressional Budget Office estimated that healthcare costs were less than 5% of the gross domestic product; by 1980, that estimate reached 8%. Now it is approaching 20%, and the Congressional Budget Office estimates that by 2025, this number will reach 25% of the gross domestic product.17Congressional Budget OfficeThe Long-Term Outlook for Health Care Spending. Congressional Budget Office, Washington DC2007www.cbo.gov/ftpdocs/88xx/doc8880/20071120_OrszagPresentation.pdfGoogle Scholar Meanwhile, the Patient Protection and Affordable Care Act, new initiatives at the Centers for Medicare and Medicaid Services, and new information technology offer a fresh opportunity to integrate public health and medicine. Whether those attempts will be successful depends largely on our ability to learn lessons from the past, in particular, the experiences with COPC and managed care.LessonsPerhaps the most striking, although not surprising, lesson learned from prior efforts to integrate medicine and primary care with public health is that efforts to improve population health require infrastructure and funding if this integration is to occur and be maintained. The medical reimbursement system supports medical piecework and provides limited support for indirect patient care activities (e.g., practice analysis or time spent on efforts to identify those in need or requiring additional support or counseling other than by physicians) to succeed. Linking medicine and public health has the potential to produce cost savings, especially through avoiding more costly hospitalizations by the tighter coordination of clinical services for populations at risk (e.g., ensuring that children with asthma and their families know how to use their medications or providing in-home clinical services for frail persons). Achieving these savings requires developing and funding an infrastructure that links practices into larger networks and provides the analytic and community intervention capacity lacking in individual practices but common to health departments. The North Carolina Medicaid program has sustained continued savings for longer than a decade by redesigning primary care services to reduce preventable admissions, often through close collaborations between primary care groups and local health departments.18Cook J. Michener J.L. Lyn M. Lobach D. Johnson F. Practice profile Community collaboration to improve care and reduce health disparities.Health Aff (Millwood). 2010; 29: 956-958Crossref PubMed Scopus (15) Google Scholar In the process, both primary care and public health change, with primary care moving such services as health education and care coordination out of the office. Additionally, public health departments are shifting from a focus on categorical services to assistance with analysis of preventable illness and to becoming partners in service delivery to populations at risk.A second lesson is to avoid counting on integration for major short-term cost savings. Prevention interventions alone can save money (e.g., vaccination and disease eradication), but they often do not realize cost savings in the short term. Companies that insure working-age adults illustrate the challenge of attributing savings to earlier funding for prevention. Savings from preventive services often occur after individuals retire, when that company no longer insures them. With the advent of Medicare Part C and the growth of Medicare managed care among commercial insurers, that is no longer as true as it was in the past, illustrating the alignment of incentives for today's activities with those who will reap later rewards.A third lesson is that change in the professional culture is needed, but such change is difficult. Physicians and the healthcare organizations for which they work have a long history of professional autonomy and personal accountability for their patients. They might find the transition to collaborative teams, especially with members of other professions and in other organizations, challenging and sometimes threatening. Bridging from the biomedical model of medicine to the social determinant and policy focus of public health is even more difficult. After a century of separation, medicine and public health no longer speak a common language, and all too often when the two come together, the medical voice is the louder. However, failure to recognize and manage the cultural change creates considerable risks, especially for public health. Otherwise, when medicine and public health are combined, medicine dominates—financially, morally, and administratively. As an illustration of this continued problem, at this writing, the healthcare bill before the U.S. House of Representatives calls for the sustained growth-rate reduction in physician Medicare reimbursement to be offset by drawing from the prevention trust fund, pitting medicine and public health against each other in the national political arena. This dramatically illustrates the difficult policy environment, prompted by the economic downturn, which threatens both public health and primary care. Yet as Abraham Flexner demonstrated, change can happen with striking speed.1Flexner A. Medical Education in the U.S. and Canada: A Report to the Carnegie Foundation for the Advancement of Teaching. Carnegie Foundation for the Advancement of Teaching, New York1910www.archive.org/details/medicaleducation00flexialaGoogle Scholar We have reason to believe that a similar transition might be upon us.What's New?An alignment of tools and incentives providing new opportunities for cost savings and system improvement exists today. Two major changes stand out. First, the Affordable Care Act has provided dollars to drive change in population health. Although the Affordable Care Act's ultimate fate will not be known for some time, it is providing new funding and new life for integrating medicine and public health. For example, the CDC's Community Transformation Grants program (www.cdc.gov/communitytransformation) provides funding for achieving broad population-based goals by calling on all of a community's resources. Similarly, the Centers for Medicare and Medicaid Services' Innovation Center is rolling out an array of programs that bring new attention to the potential for public health and primary care partnership by supporting clinical system redesign for large populations, supporting redirection of funds from inpatient care to outpatient and from treatment to prevention, and encouraging experiments designed to achieve this aim. For the first time, sustaining a flow of funds to support continued improvements in population health is possible.Second, the $27 billion being invested in electronic health records is moving health data from paper records to large-scale digital data warehouses, permitting the rapid analysis of changes in illness patterns in locations that can aggregate across sites of care, as well as the detection of previously unknown community illness clusters. This ability to aggregate data about individuals across care settings and to “roll up” these data to practices and neighborhoods largely obviates the long-standing problem of identifying the population served while also opening a new set of concerns regarding how to aggregate, attribute, and report accurately while respecting privacy.19Innovations D.H. Implementation and Information Technology Committee Meeting. Durham Health Innovations, Durham, NCSeptember 13, 2011www.dtmi.duke.edu/about-us/organization/duke-center-for-community-research/durham-health-innovations/implementation-activities/IIT-meeting-091311v3.pdf/viewGoogle Scholar Combining these tools with new policy mandates to bolster population health can allow direct, coordinated efforts to reduce disease burden and costs at the community level. The role of public health in identifying and focusing on population concerns, combined with a practice's ability to use these aggregate data for population health interventions, is an excellent illustration of this integration of information technology for medical care and population health. The New York City Primary Care Information Project supports the adoption and use of electronic health records among primary care providers in underserved communities and has demonstrated increases in preventive service delivery, including screenings as well as blood pressure and cholesterol control.20New York City Department of Health and Mental HygieneHealth Department Findings Show That Electronic Health Records Can Improve Health Care by Encouraging Preventive Services.www.nyc.gov/html/doh/html/pr2010/pr052-10.shtmlGoogle Scholar Health information exchanges (e.g., the one in Indiana) link primary care providers, hospitals, laboratories, pharmacies, and health departments to provide information exchange and two-way communication for more efficient and effective population and clinical care.21Indiana Health Information Exchange, 2011.www.ihie.comGoogle Scholar However, the fact that only $30 million (1%) of this investment was allotted to public health reveals that the public health perspective is once again regarded as secondary to traditional clinical medicine.What Now?How do we harness this moment? First, we must ensure that long-term financial support for population health is designed into new healthcare delivery and public health systems (optimally regarded as one health system). At the same time, we need to recognize the vagaries of the economy and government funding and seriously consider how effective collaborations can be sustained in a changing world. Second, we must optimize the use of electronic health records and the data they generate so that we understand more fully patterns of illness in the community. We then can use this understanding to improve prevention and care across the nation's disparate communities. Third, population health measures should be used more effectively in monitoring the nation's health and reporting not only to clinicians, health insurers, and other major healthcare actors but also to the general public and those in public health at the local, state, and federal levels. By contrast, state and local health departments should define their roles in relation to Affordable Care Act–funded organizations, medical homes, and other innovations at the intersection of population health and clinical care. Finally, and perhaps hardest of all, clinicians and public health officials should begin rebuilding their connections and collaborating to meet the needs of the communities they both serve, recognizing that the needed cultural changes are significant. If we do all these, we will have seized the moment and begun to integrate medicine and public health.ConclusionAs we did a century ago and periodically since, we appear to have the opportunity to align clinical medicine—in particular, primary care—with community health. Our challenge will be to seize the opportunity to facilitate change; measure the changes accurately, including economic impact; and communicate the process and results effectively. However, we must retain the flexibility to adapt to local variation and to social and environmental changes that inevitably will arise. We also should bring the conversation back to something more than simply cost savings, to the fundamental questions of health, quality of life, equity, and community. Perhaps the most important message is that we have had the opportunities before, but never with the same tools or the same dire outcomes if we fail to act. The impact on the economy is one of those outcomes. In today's global economy, we simply cannot afford to let this continue. An adverse impact on the nation's health will follow inevitably unless we act wisely as a nation. This time, we have no option but to accelerate the slow process of bridging the cultures of medicine and public health to the service of our communities and the nation. Multiple promising but unsustainable attempts have been made to maintain programs integrating primary care and public health since the middle of the last century. During the 1960s, social justice movements expanded access to primary care and began to integrate primary care with public health concepts both to meet community needs for medical care and to begin to address the social determinants of health. Two decades later, the managed care movement offered opportunities for integration of primary care and public health as many employers and government payers attempted to control healthcare costs and bring disease prevention strategies in line with payment mechanisms. Today, we again have

Multiple promising but unsustainable attempts have been made to maintain programs integrating primary care and public health since the middle of the last century. During the 1960s, social justice movements expanded access to primary care and began to integrate primary care with public health concepts both to meet community needs for medical care and to begin to address the social determinants of health. Two decades later, the managed care movement offered opportunities for integration of primary care and public health as many employers and government payers attempted to control health costs and bring disease prevention strategies in line with payment mechanisms. Today, we again have the opportunity to align primary care with public health to improve the community's health.

Effective national disease surveillance was an idea that captured the imagination of Alexander D. Langmuir, CDC’s chief epidemiologist for 23 years. In 1963, in his sentinel paper published in the New England Journal of Medicine (5), Langmuir separated the discipline of surveillance from the other activities of public health and emphasized the importance of systematic collection of pertinent data, consolidation and analysis of these data into useful information, and dissemination of results to persons who need to know and can take action. These concepts were argued convincingly to the World Health Assembly as the approach for monitoring communicable and noncommunicable health events; subsequently, surveillance systems were developed, and findings from these systems were highlighted in a special issue (volume 5, number 1) of the International Journal of Epidemiology in 1976. During the 50 years since Langmuir published his concept of public health surveillance, developments in four areas have changed the field: 1) national coordination, 2) technology and informatics, 3) expansion beyond communicable diseases, and 4) methodologic development. Through these, however, the core definition and integrity of surveillance practice have remained unchanged.

Since 1946, the Centers for Disease Control and Prevention has responded to urgent requests from US states, federal agencies, and international organizations through epidemic-assistance investigations (Epi-Aids). The authors describe the first 60 years of Epi-Aids, breadth of problems addressed, evolution of methodologies, scope of activities, and impact of investigations on population health. They reviewed Epi-Aid reports and EIS Bulletins, contacted current and former Epidemic Intelligence Service staff, and systematically searched the PubMed and Web of Science databases. They abstracted information on dates, location, staff involved, health problems, methods, and impacts of investigations according to a preplanned protocol. They assessed the methods presented as well as the quality of reports. During 1946-2005, a total of 4,484 investigations of health events were initiated by 2,815 Epidemic Intelligence Service officers. In the early years, the majority were in response to infectious agents, although environmental problems emerged. Investigations in subsequent years focused on occupational conditions, birth defects, reproductive health, tobacco use, cancer, violence, legal debate, and terrorism. These Epi-Aids heralded expansion of the agency's mission and presented new methods in statistics and epidemiology. Recommendations from Epi-Aids led to policy implementation, evaluation, or modification. Epi-Aids provide the Centers for Disease Control and Prevention with the agility to respond rapidly to public health crises.

The past decade has brought substantial changes in how data related to a community's health are collected, stored, and used to inform decisions about health interventions. Despite these changes, the purpose of public health surveillance has remained constant for more than a century. Public health surveillance is the ongoing, systematic collection, analysis, and interpretation of health-related data with the a priori purpose of preventing or controlling disease or injury, or of identifying unusual events of public health importance, followed by the dissemination and use of information for public health action. Surveillance is an important and necessary contributor to knowledge of a community's health. The public health system is responsible for ensuring that public health surveillance is conducted with appropriate practices and safeguards in order to maintain the public's trust.

Hepatitis E — Continued Outbreaks of hepatitis E (i.e., enterically transmitted non-A, non-B hepatitis) have occurred in some parts of the world and have generally been related to contaminated water supplies. Until recently, when research-based serologic tests ( 1,2 ) were developed to test for antibody to hepatitis E virus (anti-HEV), no serologic test was available to identify HEV infection, and diagnosis depended on a history of exposure in an appropriate epidemiologic setting and the exclusion of other causes of viral hepatitis. During 1989–1992, acute HEV infection was documented among six persons in the United States who had returned from international travel. This report summarizes CDC’s serologic document ation of acute HEV infection—presumed to have been acquired during international travel—in four of these persons.

The term shoe-leather epidemiology is often synonymous with field epidemiology or intervention epidemiology. All 3 terms imply investigations initiated in response to urgent public health problems and for which the investigative team does much of its work in the field (i.e., outside the office or laboratory). Alexander D. Langmuir is credited with articulating the concept of disease surveillance as it is applied to populations rather than individuals. He also founded the Epidemic Intelligence Service (EIS) Program in 1951, a 2-year training experience in applied epidemiology that places professionals in the field, domestically and internationally, in real-life situations. Today, 70-90 EIS officers are assigned each year to Centers for Disease Control and Prevention programs and to state and local health departments to meet the broad spectrum of challenges in chronic disease, injury prevention, violence, environmental health, occupational safety and health, and maternal and child health, as well as infectious diseases. Throughout their assignments, EIS officers are encouraged to strive for analytic rigor as well as public health consequence, which requires technical competence blended with good judgment and awareness of context. Effective applied epidemiologists must have skills beyond just epidemiology to improve a population's health; the field of applied epidemiology requires multiple team members, all having different but complementary skills, to be effective.

Objective: Recent studies indicate continuing health disparities across geographic units in the US. This paper provides updated estimates of the association between socioeconomic factors and population health using a new state-level dataset and panel econometric methods that account for state-specific effects and autoregressive error structure.Methods: Data from multiple sources for the 50 US states and the District of Columbia are merged. The dependent variables are age-adjusted all-cause mortality, self-assessed health status, and number of healthy days. Panel econometric models are used to accommodate state-specific unobserved factors and to incorporate autoregressive random disturbances to provide consistent and robust estimates.Results: A 1-unit increase in the number of physicians per 1000 population is associated with a reduction in mortality by 30/100,000. The effects of physician-to-population ratio on self-reported health measures are mixed. Socioeconomic, demographic, as well as the prevalence of smoking and obesity have varying effects on mortality and self-reported measures of health.Conclusions:The new estimate of the association between physician supply and lower mortality suggests continuing efforts to assess the need for policies and incentives to induce physician labor supply in underserved states. Strategies and policies to reduce health disparities should address social, economic and individual risk factors. Published by Elsevier Ireland Ltd.

This chapter summarizes key points from the book, including the stability of the definition of public health surveillance, and the importance of planning a system with defined outputs and a specific public health purpose. Public health surveillance systems are designed to produce information about a population from which the data are collected in order to prevent or control disease or injury, or to identify an unusual event of public health importance. The chapter outlines three challenges and opportunities for surveillance. The first involves finding the discipline's right place under the broadly conceived umbrella of “health knowledge” and finding a common lexicon for all health data collections. The second is reconciling the increased ability to amass identifiable data without a specific intended use with the ethical principles that must guide public health data collection, storage, and use. The third is to ensure a versatile and agile public health surveillance workforce, equipped to deal with many aspects of measuring and responding to health problems in a community.

Objectives. From 2004 through 2005, as part of a major strategic planning process called the Futures Initiative, the Centers for Disease Control and Prevention (CDC) developed a set of Health Protection Goals to make the best use of agency resources to achieve health impact. These goals were framed in terms of people, places, preparedness, and global health. This article presents a goals framework and a set of health outcome measures with historical trends and forecasts to track progress toward the Healthy People goals by life stage (Infants and Toddlers, Children, Adolescents, Adults, and Older Adults and Seniors). Methods. Measurable key health outcomes were chosen for each life stage to capture the multidimensional aspects of health, including mortality, morbidity, perceived health, and lifestyle factors. Analytic methods involved identifying nationally representative data sources, reviewing 20-year trends generally ranging from 1984 through 2005, and using time-series techniques to forecast measures by life stage until 2015. Results. Improvements in measures of mortality and morbidity were noted among all life stages during the study period except Adults, who reported continued declining trends in perceived health status. Although certain behavioral indicators (e.g., prevalence of nonsmokers) revealed steady improvements among Adolescents, Adults, and Older Adults and Seniors, prevalence of the healthy weight indicator was declining steadily among Children and Adolescents and dramatically among Adults and Older Adults and Seniors. Conclusion. The health indicators for the Healthy People goals established a baseline assessment of population health, which will be monitored on an ongoing basis to measure progress in maximizing health and achieving one component of CDC's Health Protection Goals.