What Is Epidemiology


What is Epidemiology?

Epidemiology is a branch of medical science that deals with the incidence, prevalence, distribution, and control of disease in a population. Unlike other medical disciplines, epidemiology concerns itself with groups of people rather than individual patients. It is frequently historical and statistical in nature. Epidemiologists can focus on a subset of health science including cardiovascular, cerebrovascular diseases, cancer, infectious diseases including HIV/AIDS, digestive diseases, congenital malformations, psychiatric and psychological disorders, genetic diseases, environmental health, veterinary epidemiology, and dental epidemiology (Ross, 1998.) Epidemiology falls under the umbrella of “public health.”

What Do Epidemiologists Do?

Epidemiologists are the first to identify a disease as it occurs in a population. Then they track the disease as it moves through the population using statistics, demography, and sound research methods. Epidemiologists work to develop methods that prevent or control the spread of a disease. Epidemiologists work for universities and research organizations; international, federal, state, and local health departments; major healthcare organizations; and medical, pharmaceutical, and diagnostics companies. Some epidemiologists work in the corporate sector as market research analysts.

Information Needs of the Epidemiologist

The epidemiologist needs to be able to access research sources throughout his or her professional career. Whether studying a new methodology, checking on exposure limits, learning about diseases not previously of interest or even not previously known, or finding already-collected data to test a hypothesis, the epidemiologist needs to know how to access information or data efficiently and effectively. The epidemiologist also must be able to judge the information or data that he finds, whether by internal or external criteria, and to use and present it appropriately.

As the epidemiologist’s information needs have been growing, so have the information sources and information itself. The surge in growth is also partly because of the rapid development of electronic resources. As Friede (1995) notes, the transition of volumes of data to searchable, electronic databases has accelerated the demand and the growth of epidemiological research. In fact, the development of electronic databases and the posting of statistical information on the web by government agencies have provided the impetus for newer and larger information resources. However, training has also become an important issue with the development of electronic and web sources. The epidemiologist must know effective search strategies and understand how the database is constructed. The epidemiologist must also develop critical evaluation skills and recognize when web sources are out-of-date or suspect.

The epidemiologist has information needs ranging from the clinical to the logistical to the statistical. Libraries and information professionals are not suited to address the more clinical and analytic information needs of epidemiologists. Clinical information can be obtained generally only through the publication of government research or notification of new diagnoses by physicians in electronic reporting databases. The responsibility and control for these undertakings lies outside the realm of library and information science.

Logistical information needs include the access to electronic reporting data and access to remote scheduling programs to facilitate communication with other public health workers while working in the field. The training and use of palm pilots to assist with communication and scheduling concerns seems the most sensible solution to logistical information needs.

However, the epidemiologist also needs to utilize resources at the other end of the information spectrum, namely the statistical sources. These statistical sources are usually collected and/or collated by government or similar agencies. They are usually repeated over time (e.g., U.S. Census every ten years), allowing the epidemiologist to track a population shift, a change in the pattern of disease occurrence, or the distribution of risk factors (O’Carroll, 1998.)

Friede (1995) and Baker (1995) discuss several caveats for the use of these statistical sources. First, much of the data has been collected for purposes other than epidemiological studies. Second, the information may have been collected at inconvenient intervals (usually too long). Third, age, race, gender, or other factors may not have been appropriately distributed (e.g., ages 10-19 years old for fertility studies). Fourth, important information may not have been included in the data collection (e.g., race/ethnicity). Fifth, data may be sampled either to fill in time intervals (U.S. Census) or to incorporate statistics not otherwise available (NCHS special studies).

These caveats should not deter epidemiologists from utilizing this information. Much of the information needed by epidemiologists is available in no other way. However, epidemiologists must treat incomplete information with caution.

Patricia Quinlisk, MD, MPH, is the Director and State Epidemiologist for the Iowa Department of Health. She is a leading authority in epidemiology and graciously agreed to an interview conducted via e-mail correspondence. Lack of access to information is the one of the most formidable barriers facing the public health profession, says Quinlisk. Sometimes information doesn’t exist because no agency or organization has collected data, but often extant resources aren’t utilized because the epidemiologist isn’t aware of the resources or because he or she has no access to the data. The data may be in the form of an electronic database or publication that the epidemiologist can’t afford, or the data may be still in its raw form – volumes of pages – and the epidemiologist is expected to sift through and interpret the data. “This is a daunting task,” she says, “and epidemiologists don’t have simply enough time, or the epidemiologist may not understand the organization and collection of the data and cannot make sense of it.”

Larger issues facing the public health profession include the lack of communication between health communities, which makes information nearly impossible to obtain. Quinlisk says, “Although the public health and medical communities coexist, we need to have a better understanding of each other’s roles and abilities, allowing better coordination. For example, public health needs to know the number of isolation rooms available, in the event that quarantine of individuals is necessary. Conversely, medical professionals need to understand the critical nature of reporting patients with certain syndromes. Also, those outside the health community often lump medical and public health together yet very different roles will be played by these entities during an epidemic.”

“Public health relies heavily on the medical community to tell us what they are seeing, even with rapid electronic reporting and analysis of disease occurrence,” continues Quinlisk. “A good example of this is West Nile Virus. New York City probably has one of the best tracking systems for diseases, and yet it was a single physician—who had attended a seminar by a member of the health department—who, when she saw two cases of encephalitis with unusual manifestations, thought to pick up the phone and call the health department. Thus the outbreak was identified. Medical and public health professionals have traditionally relied on these types of informal connections for information, and they will continue to be important in the future. However, this means public health must become more visible to the medical community, must conduct more educational events to increase medical professionals’ awareness of public health, and must impress upon those in the medical community about the critical role they will play in identifying, reporting and responding to an outbreak of infectious disease or even a terrorist event. This task must be accomplished in an environment of increasing time pressure on health care professionals.”

From my interviews with Dr. Quinlisk, I believe these are likely unmet needs that could be addressed for epidemiologists:

1. Lack of critical communication between public health entities, between public health emergency response agencies, and with the public.

2. Little coordination with public health agencies in planning, training, and exercise

3. Lack of established national standards and protocols for surveillance, identification, follow-up procedures and methods; and for reporting critical information, including mandatory reporting procedures

4. Lack of clarification of the proper authorities and procedures for public health involvement in awareness of potential epidemics, emergence of infectious disease or bioterrorism

5.  Lack of access to health insurance billing data

6.  Lack of access to criminal justice data

7.  Lack of access to academic and state experts

8.  Underdevelopment of group-specific electronic discussion lists

9. Lack of remote access to office systems and meetings; (scheduling software & resources)

It would be difficult, however, for the library and information community to provide solutions for these information needs. Most of the responsibility for each of these needs rests with the public health and medical professions and leading national institutions and agencies. They are worth noting, however, to provide a framework for the breakdown in information in the public health profession and emphasize how heavily epidemiologists rely on services provided by libraries in order to obtain critical information.

Unmet Needs of Epidemiologists at the Library

I interviewed William Olmstadt, Librarian at the Medical Sciences Library, of Texas A&M University to gauge the health sciences librarian’s perspective. I was interested in the types of queries asked by epidemiologists at Texas A&M, and the unmet information needs of these patrons.

Olmstadt explained that the epidemiologists who patronize the Medical Sciences Library often are looking for access to electronic databases that are not provided by their own county, government, or other agencies. The databases include commonly used data sets like the National Health Interview Survey or more complicated data sets, like the NHANES, which require more sophisticated interfaces. The access to these tools is the most sought after service provided by the librarians at the Medical Sciences Library.

A second need that is strongly noticed at the Medical Sciences Library is a central framework of databases and other sources that are of interest to epidemiologists. Epidemiology is a highly interdisciplinary field, with many specializations. Statistical data and case studies are often obtained from a variety of sources, including databases and serials from the disciplines of medicine, psychology, public policy, sociology, dental medicine, agriculture, and veterinary medicine. A frustration expressed by many epidemiologists who visit the Medical Sciences Library is that no central location or portal exists from where epidemiologists may access all of the tools and information sources they might require. Visits to other specialized libraries are often necessary. Olmstadt suggested that this is the most prominent unmet need of their epidemiologist patron base, and the Library is evaluating the possibility of OPAC stations fully equipped with public health data sets and customized solely for use by epidemiologists.

Another unmet need mentioned by Olmstadt and Quinlisk is the lack of librarians and other information professionals who are specialized in epidemiology and public health. Quinlisk expressed her frustration with librarians who have little or no familiarity with the profession and cannot understand the discourse used by epidemiologists or the interdisciplinary nature of the profession. Olmstadt echoed Quinlisk’s sentiments: “I am not familiar with the framework of public health. Epidemiology and public health is only a small fraction of the disciplines served by the Medical Sciences Library, and very little training is provided to help me understand their role in healthcare. The sources that might be the most helpful for epidemiologists are frequently not part of our core training or focus. We are not wholly familiar with the scope and content of these databases and therefore cannot help epidemiologists with effective searches or referrals.”

Therefore, I am inclined to identify four additional unmet needs. These needs appear to exist for both the epidemiologists and the information professionals who serve them. These needs could be addressed and corrected by the library and information community.

1.  Lack of access to information technology and retrieval software

2.  Lack of knowledgeable librarians or information professionals

3.  Lack of awareness of available resources and appropriate training

4.  Uneven distribution of relevant information across disciplines

How Can Libraries Meet These Needs?

The adoption of an OPAC designed to suit the needs of epidemiologists is an excellent solution to some of the unmet needs. The OPAC should have the databases and electronic data sets referred to in Parts A and B installed on the hard drive. A librarian with a thorough grounding in public health should peruse web sites and the electronic journals of other disciplines and provide access to relevant titles on the OPAC. Also, the librarians should be very familiar with the construction of the databases to assist in developing effective search strategies and the development of training programs for the epidemiologist patron base. The National Library of Medicine, in response to a needs assessment conducted in partnership with the Centers for Disease Control, has developed a training program specifically for librarians in regards to these databases and public health information (Humphreys, 1999.)

However, OPACs would serve the information needs of only those epidemiologists who are associated with or have access to research libraries. Given the small number of public health programs in the U.S., it seems likely that few health sciences libraries would be concerned with the specific needs of epidemiologists. There is, perhaps, a better way to reach epidemiologists, especially those working in the field. I propose the idea of a web portal, assuming that even epidemiologists in the field can gain access to the Internet through perhaps a palm pilot or public library.

A web portal is a term, generally synonymous with gateway, for a web site that is or proposes to be a major starting site for users when they get connected to the web or that users tend to visit as an anchor site. There are general portals and specialized or niche portals. Some major general portals include Yahoo, Excite, Netscape, Lycos, CNET, Microsoft Network, and America Online's AOL.com.

A number of large access providers offer portals to the web for their own users. Most portals have adopted the Yahoo style of content categories with a text-intensive, faster loading page that visitors will find easy to use and to return to. Typical services offered by portal sites include a directory of web sites, a facility to search for other sites, news, weather information, e-mail, stock quotes, phone and map information, and sometimes a community forum. Excite was among the first portals to offer users the ability to create a site that is personalized for individual interests.

A web portal designed for epidemiologists would include access to electronic databases, directories of associations and professional organizations of interest, community forums (like a bulletin board), and perhaps an electronic data reporting system like the one mentioned by Dr. Quinlisk. Perhaps if access to the web portal is provided to physicians, then the convenience might encourage physicians to report incidences of diseases faster and more often. It might form a kind of unofficial disease tracking system. Epidemiologists could register with the portal, log in, and read the new incidents of diseases that were report or read and respond to situations from epidemiologists in the field. Perhaps scheduling software, similar to the type used by Yahoo, could be designed that allows epidemiologists to communicate with each other and schedule appointments and meeting while in the field. A web portal is an undertaking of great magnitude and requires significant data collection and effort on the part of the “webmaster.” However, this may be a service that a national agency or institution such as the National Library of Medicine or the Centers for Disease Control would be interested in pursuing.