Adult Blood Lead Epidemiology and Surveillance Program (ABLES): A surveillance system for identifying and preventing cases of elevated blood levels (BLLs) among workers in the United States. Twenty-eight States participated in ABLES in 1999 by collecting laboratory-reported blood lead results and by targeting high-risk industries and occupations, physicians, workers, and worksites for outreach, intervention, and research.

American Association of Poison Control Centers: A nationwide resource that provides information about all aspects of poisoning and refers patients to treatment centers.

Causality: The relating of causes to the effects they produce. Most of epidemiology concerns causality, and several types of causes can be distinguished. It must be emphasized, however, that epidemiologic evidence by itself is insufficient to establish causality, although it can provide powerful circumstantial evidence. A cause is termed "necessary" when it must always precede an effect. This effect need not be the sole result of the one cause. A cause is termed "sufficient" when it inevitably initiates or produces an effect. Any given cause may be necessary, sufficient, neither, or both.

CDC National HIV/AIDS Reporting System (HARS): This Centers for Disease Control and Prevention (CDC) reporting system contains information about U.S. AIDS and HIV case reports, including data by State, metropolitan statistical area, mode of exposure to HIV, sex, race/ethnicity, age group, vital status, and case definition category.

Census of Fatal Occupational Injuries (CFOI): A national census of occupational injury fatalities, including selfemployed workers, agricultural workers, and government workers. CFOI uses multiple sources of information such as death certificates, OSHA reports, workers' compensation data, police reports, and newspaper clippings. CFOI program data are collected in cooperation with BLS to ensure that data are comparable among States. States provide data to BLS for inclusion in a national database and maintain their own State databases. Data are currently available for the years 1992–1997.

Coal Workers' X-Ray Surveillance Program (CWXSP): An ongoing, congressionally mandated program to provide periodic chest X-rays to working underground coal miners for identifying early pneumoconiosis and facilitating the transfer of affected workers to a job with lower dust concentrations. The program has been in effect since 1970.

Etiology: Literally, the science of causes; causality; in common usage, cause. See also causality and pathogenesis.

Fatality Assessment and Control Evaluation (FACE): A National Institute for Occupational Safety and Health (NIOSH) field investigation program with two arms: (1) a NIOSH/State cooperative program in which 15 States conduct State censuses of fatal occupational injuries and investigate specific types of these; and (2) a NIOSH intramural program that investigates specific types of fatalities at the request of 5 States. Fatalities specifically investigated by FACE include falls, machinery-related events, and logging fatalities.

Incidence rate: The rate at which new events occur in a population. The numerator is the number of new events that occur in a defined period; the denominator is the population at risk of experiencing the event during this period, sometimes expressed as person-time.

Long latency period: (Synonym: latency.) Delay between exposure to a disease-causing agent and manifestation of the disease. For example, after exposure to ionizing radiation, the average latency period is 5 years before the development of leukemia and more than 20 years before the development of certain other malignant conditions. The term latent period or latency is often used synonymously with induction period (the period between exposure to a disease-causing agent and manifestation of the disease). Latency has also been defined as the period from disease initiation to disease detection. In infectious disease epidemiology, this period corresponds with the period between exposure and onset of infectiousness (which may be shorter or longer than the incubation period).

Median: A measure of central tendency. The simplest division of a set of measurements is into two parts—the lower and the upper half. The point on the scale that divides the group in this way is called the "median."

National Center for Health Statistics (NCHS): A center within CDC that is responsible for the collection, analyses, and dissemination of health statistics. NCHS has two major types of data systems: systems based on population data collected through personal interviews or examinations; systems based on individual records, with data collected from State and local vital and medical records.

National Center for Infectious Diseases (NCID): A center within CDC whose mission is to prevent illness, disability, and death caused by infectious diseases in the United States and around the world. NCID accomplishes its mission by conducting surveillance, epidemic investigations, epidemiologic and laboratory research, training, and public education programs to develop, evaluate, and promote prevention and control strategies for infectious diseases.

National Electronic Injury Surveillance System (NEISS): A data system maintained by the Consumer Product Safety Commission (CPSC) to monitor consumer-product-related injuries representing a national sample of U.S. emergency departments. In an interagency agreement with NIOSH, NEISS also collects and codes data on all work-related injuries from emergency departments, regardless of consumer product involvement.

National Health and Nutrition Examination Survey (NHANES): An ongoing Federal survey administered by the National Center for Health Statistics (NCHS) to provide researchers with information about the health and nutrition status of the U.S. population, prevalence of selected diseases, and associated risk factors.

National Hospital Ambulatory Medical Care Survey (NHAMCS): A national survey designed to collect data on the utilization and provision of ambulatory care services in hospital emergency and outpatient departments. Findings are based on a national sample of visits to the emergency departments and outpatient departments of approximately 500 noninstitutional general and shortstay hospitals. Annual surveys were begun in 1992.

National Occupational Mortality Surveillance System (NOMS): A mortality statistics database derived from public-use vital statistics data disseminated by the National Center for Health Statistics (NCHS). Since the early 1980s, NIOSH, NCHS, and the National Cancer Institute have supported the collection and coding of decedents' usual occupation and industry information for State vital statistics programs. NOMS uses data from these cooperating States and States that received cooperative agreements through early NIOSH State-based surveillance programs. Usual occupation and industry of the decedent are coded according to the Bureau of the Census classification system. Cause of death is coded according to the World Health Organization's Manual of the International Statistical Classification of Diseases, Injuries, and Causes of Death, Based on Recommendations of the Ninth Revision Conference, 1975.

National Surveillance System for Hospital Health Care Workers (NaSH): A surveillance system that focuses on surveillance of exposures and infections among hospital-based health care workers. The purpose of NaSH is to monitor national trends; identify newly emerging hazards for HCWs; assess the risk of occupational infection; and evaluate preventive measures, including engineering controls, work practices, protective equipment, and postexposure prophylaxis to prevent occupationally acquired infections.

National Surveillance System for Pneumoconiosis Mortality (NSSPM): An annually updated pneumoconiosis surveillance system developed by NIOSH. The NSSPM includes information about all U.S. decedents with death-certificate mention of pneumoconiosis since 1968. The system is based on death certificate data files made available annually by the National Center for Health Statistics (NCHS). Records are currently available for more than 100,000 pneumoconiosis decedents; they include information about demographic characteristics, year of death, underlying and contributing causes of death, and (since 1985 for deaths occurring in about half of the States) usual industry and occupation.

National Traumatic Occupational Fatalities Surveillance System (NTOF): A nationwide surveillance system for occupational injury deaths. NTOF is based on death certificates as a sole source of case identification. The system has been estimated to include an average of 81% of all occupational injury deaths nationwide. NTOF data are currently available for 1980 through 1995. NTOF is the most comprehensive source of data on occupational injury deaths before 1992.

Noise-induced hearing loss: A sensorineural hearing loss caused by repeated exposure to high-intensity sound levels. Noise-induced hearing loss is characterized by irreversible damage to the sensory hair cells located within the inner ear. The condition is usually preventable by limiting noise exposures or by using personal hearing protective devices.

Pathogenesis: The postulated mechanisms by which the etiologic agent produces disease. The difference between etiology and pathogenesis should be noted: The etiology of a disease or disability consists of the postulated causes that initiate the pathogenetic mechanisms. Control of these causes might lead to prevention of the disease.

Prevalence rate (ratio): The total number of all persons who have an attribute or disease at a particular time (or during a particular period) divided by the population at risk of having the attribute or disease at this point in time or midway through the period. A problem may arise with calculating period prevalence rates because of the difficulty of defining the most appropriate denominator. This is a proportion, not a rate.

Proportionate mortality ratio (PMR): Ratio of the proportion of deaths from a specific cause in an exposed population compared with the comparable ratio in the nonexposed population. For example, the proportion of deaths from disease X in the exposed population could be compared with the proportion of deaths from disease X in the nonexposed population.

Sentinel Event Notification System for Occupational Risk (SENSOR): A NIOSH cooperative agreement with State health departments or other State agencies that develops generalizable, conditionspecific strategies for Statebased surveillance of occupational diseases and injuries. Efforts have focused on standardization of variables collected by the State programs, creation of software to facilitate adoption of the surveillance systems by additional States, comparison of SENSOR findings to other surveillance data sources, collaboration with the Council of State and Territorial Epidemiologists (CSTE) on building infrastructure for Statebased surveillance, further development of Statebased hazard surveillance, and publication and dissemination of SENSOR reports.

Surveillance for Tuberculosis Infection in Health Care Workers (staffTRAK–TB): CDC recommends periodic tuberculosis (TB) skin testing of health care workers with potential for exposure to Mycobacterium tuberculosis. staffTRAK–TB was developed to track, analyze, and report demographic, occupation, work location, and multiple TB skin-testing results to determine whether clinically active TB is present.

Surveillance: The systematic, ongoing collection and/or acquisition of information for occupational diseases, injuries, and hazards. Surveillance includes the analysis and interpretation of surveillance data, the dissemination of data or information derived from surveillance to appropriate audiences for prevention and control, and the development of surveillance methodology.

Survey of Occupational Injuries and Illnesses (SOII): An annual survey of a large sample of U.S. employers (approximately 250,000) maintained by the Bureau of Labor Statistics (BLS). The sample is drawn to provide national and State estimates for those States that participate in this Federal/State cooperative program (about 40). The annual survey excludes government workers, the self-employed, and employees of small farms. Employers report information from their injury and illness logs. For employers not required to keep logs, recordkeeping forms are provided at the beginning of the study period.

Toxic Exposure Surveillance System (TESS): A State-based surveillance system for identifying, investigating, and preventing pesticide-related illnesses and injuries. TESS is maintained by the American Association of Poison Control Centers.

Viral Hepatitis Surveillance Program (VHSP): The Hepatitis Branch of the National Center for Infectious Diseases (NCID) operates the Viral Hepatitis Surveillance Program (VHSP), which obtains national surveillance data on clinical, serologic, and epidemiologic data pertaining to risk factors for viral hepatitis.