Epidemiology Flashcards
(133 cards)
1
Q
Activities of daily living (ADL) scale
A
A scale for recording a person’s functional capability based on answers to questions about mobility, self-care, grooming and ability to dress, wash, keep house, shop for food. The ADL scale and many modifications assign a numerical score to physical ability and outcomes of interventions for people with known or suspected disabilities, such as those caused by arthritis. The ADL scale is used to assess health status and to evaluate progress and response to treatment.
2
Q
Acute
A
Referring to a disease or condition, this means sudden in onset, loosely used [in everyday lay language] to mean severe or intense. [This use is to be discouraged in medical parlance] See also and contrast CHRONIC.
3
Q
Adherence
A
Health-related behaviour that abides by the recommendations of a health care professional or the investigator in a research project. The word “adherence” is preferred by some who consider the alternative, COMPLIANCE, to imply coercion or excessive authoritarianism.
4
Q
Adiposity
A
Overall expansion of body fat, often with depletion of muscle mass, physical strength, and agility.
5
Q
Allocative efficiency
A
A terms used by health economists to describe the degree to which resources are allocated efficiently. The economic analysis may or may not take ethical issues into account, and equitable resource allocation is as important as economic efficiency. See also EFFICENCY.
6
Q
Ambulatory care
A
Literally, medical care of people who are able to walk in and out of a clinic. The care may be primary, episodic, or part of continuing care for an existing condition.
7
Q
Antecedent cause of death
A
The condition(s) that led to or precipitated the immediate cause of death, as recorded on a DEATH CERTIFICATE. For example, myocardial ischemia caused by coronary artery disease is an antecedent cause of heart failure (the IMMEDIATE CAUSE OF DEATH), where the underlying cause is coronary arterial atherosclerosis.
8
Q
Antenatal
A
Literally, before birth; pertaining to the provision of services for pregnant women and for their unborn children.
9
Q
Avoidable risk
A
The risk of disease at some unspecified future period that could be avoided by a specified shift to a more favourable exposure distribution of recognized risks. For example, the risk of disease and premature death from smoking-related diseases could be reduced by reduction of smoking rates.
10
Q
Barker hypothesis
A
Syn: THRIFTY PHENOTYPE HYPOTHESIS. A hypothesis proposed in 1990 by the British epidemiologist David Barker that INTRAUTERINE GROWTH RETARDATION, low birth weight, and premature birth have a causal relationship to the origins of hypertension, coronary heart disease, and type 2 diabetes, in middle age. Barker’s hypothesis derived from a RETROSPECTIVE COHORT STUDY that revealed a significant ASSOCIATION between the occurrence of hypertension and coronary heart disease in middle age and premature birth or low birth weight.
11
Q
Bayesian inference
A
A form of reasoning widely used in CLINICAL EPIDEMIOLOGY. It begins with description of the facts before exposure or intervention under investigation and adds fresh information gathered during the course of study to yield probabilities of the state of affairs after the exposure or intervention.
12
Q
Behavioural risk factors
A
These are common risk factors associated with ways people behave. They include taking insufficient physical activity, eating to excess, smoking, overindulgence in alcohol and other mood-modifying substances, reckless driving, and aggressive and violent conduct toward others, all of which are associated causally with disease, injury, and premature death.
13
Q
Benefit-cost ratio
A
The ratio of quantifiable benefits to actual or estimated costs expressed in monetary terms. It is used to assess the economic feasibility or success of a health intervention. The term COST-BENEFIT RATIO is more often used.
14
Q
Biological plausibility
A
The criterion that an observed, presumed or putatively causal association is coherent with previously existing biological or medical knowledge.
15
Q
Body mass index (BMI)
A
The body weight in kilograms divided by the square of the height in metres. This anthropometric measure is an indicator of fatness and obesity. It correlates closely with skinfold thickness and density of the body.
16
Q
Burden of disease
A
The amount of ill health from a given cause (disease, injury, cause of disease, or risk factor) in a population of interest. See also DISABILTY-ADJUSTED LIFE YEARS (DALYs).
17
Q
Burkitt’s lymphoma
A
A malignant lymphoma first identified in East Africa, where the British surgeon Denis Burkitt (1911-1993) observed that its distribution coincided with that of malaria-carrying anopheline mosquitoes, and this recognized that the condition was probably caused by an agent transmitted by mosquitoes. This agent was found to be a herpes virus, the Epstein-Barr virus, which has been detected in more than 95% of cases.
18
Q
Capitation
A
A method of payment for services based on the number of people registered as potential users of the service, rather than on fees for each item of service rendered. The basis for part of the payment of general practices under the UK’s General Medical Services (GMS) contract.
19
Q
Carstairs index
A
A measure developed in a similar fashion to the TOWNSEND INDEX to classify localities in relation to social deprivation. The index is based on four measures recorded in the UK census: low social class, lack of car ownership, overcrowding and male unemployment.
20
Q
Cause
A
In general, something that produces an effect. In medicine and public health it is customary to distinguish NECESSARY CAUSE and SUFFICIENT CAUSE.
21
Q
Cause-specific rate
A
The incidence or death rate from a specific cause such as cancer or coronary heart disease. Cause-specific incidence and death rates for cancer are further classified by the site of the cancer to yield rates for common cancers, such as lung, breast, prostate, and colon.
22
Q
Clinical Epidemiology
A
Epidemiological study conducted in the clinical setting with patients as the subjects of study.
23
Q
Clinical significance
A
A difference in effect size considered to be important in clinical or policy decision Cf. STATISTICAL SIGNIFICANCE.
24
Q
Cluster
A
A collection of events such as new cases of an uncommon or rare disease that occur so closely together in space and/or time as to arouse suspicion that this is not a chance occurrence but has a cause that should be investigated.
25
Cluster analysis
A set of mathematical and statistical procedures that are used to calculate the probability that a presumed cluster of cases is an epidemic, not a random event.
26
Community diagnosis
A term used to describe the summarized health and social statistics of a defined community, whether it be a nation or a social group within the nation.
27
Completed fertility rate
The cumulative fertility rate in a cohort of women who have passed the end of their reproductive life, e.g. the total number of births per 1,000 to women aged 49 years and older in a specified population.
28
Compliance
Abiding by the advice or instructions of a health professional. Many behavioral scientists prefer to allude to ADHERENCE and suggest that “compliance” is a pejorative word, implying coercion.
29
Cost
The value of resources invested in a service, including costs of buildings, equipment, etc., operating cost of upkeep, maintenance, wages and salaries, dressings, medications, etc., each separately itemized in the budget that records where the money comes from and where it goes. Economists, accountants, and auditors distinguish several aspects, including DIRECT, FIXED, INDIRECT, MARGINAL, OPPORTUNITY, UNIT and VARIABLE costs.
30
Cost-benefit analysis
Calculation or estimation of monetary and other costs, social costs such as time lost from work, years of active life lost to disability and premature death, and an estimate of the financial benefits attributable to the activities of a health service. All are expressed as far as possible in monetary terms. The benefits include ability to engage in work and valued familial and social activities, and estimates of added years of active productive life. Value judgments and approximations are inevitable parts of many costs-benefit analyses.
31
Cost-benefit ratio
The ratio of quantifiable costs to actual or estimated benefits expressed in monetary terms. It is used to assess the economic feasibility or success of a health intervention. See also BENEFIT-COST RATIO.
32
Cost-effectiveness
The ratio of quantifiable costs to actual or estimated benefits expressed in monetary terms. It is used to assess the economic feasibility or success of a health intervention. See also BENEFIT-COST RATIO.
33
Cost-effectiveness
Estimation of expenditure and “returns” on this expenditure as health gains, compared with what might have been achieved by using available funds in another way.
34
Cost-effectiveness analysis
A variant of COST-BENEFIT ANALYSIS that seeks to identify the least costly way to meet a specified objective. It may be conducted by comparing costs and outcomes in systems that have applied different modalities, or as an abstract exercise using economic and other modelling techniques.
35
Cost-utility analysis
A variation of COST-EFFECTIVENESS ANALYSIS in which the UTILITY of an action or a system is estimated. Utility means the merits, or value, of a specified state of health, such as a health state on the continuum from full functional status to total dependency on others.
36
Coverage
1. The extent to which the health services provided for or available to the population of a country or region meet the potential or perceived needs of the people. 2. The extent to which a population is protected against a communicable disease by appropriate vaccination or other preventing regimen. 3. The extent to which a screening programme reaches its target population (e.g. the proportion of women eligible for mammographic breast cancer screening who receive invitations to be screened.
37
Chronic
Prolonged, long lasting or long term in relation to illness. Chronic diseases are frequently referred to now as “long term conditions”.
38
Data protection
Procedures adopted to ensure that the confidentiality of sensitive personal information is maintained. Examples include secure record storage systems (filing cabinets that are locked at all times and accessible only with a key held by authorized persons) and encryption of computer-stored files to ensure that they are accessible only to authorized persons who possess the access code
39
Death Certificate
A document, signed (in most countries) by a registered doctor containing personal details (name, date of birth, place of residence etc.) of the deceased together with the suspected or established cause of death.
40
Death registration
The formal procedure of recording and notifying death has been a statutory legal requirement in most countries for more than 100 years. The details are contained in the death certificate. This is a legal document, as well as the source of tabulated data on causes of death.
41
Demand
A term used in economics to describe willingness or ability to pay for goods or services. In the terminology of health economics, it means desire for or willingness to seek health care.
42
Demography
The scientific study of populations that focuses on their size, distribution, age structure, fertility, marital patterns, migrations, mortality, and the social, cultural, economic, and other determinants of variations in any or all of these features.
43
Deprivation
In public health, this term usually applies to the status of people who are deprived of food, shelter, adequate clothing, or other necessities of life, such as protective immunizations against common infectious diseases. Deprivation scores such as TOWNSEND and CARSTAIRS are used to classify localities in the UK.
44
Determinant
Any factor, whether event, characteristic, or other definable entity, that brings about a change in a disease or health-related state. It could be inherited or acquired. The former are usually termed genetic, the latter environmental. Environmental determinants may be biological, behavioural, social, economic, cultural or other factors.
45
Direct cost
The economic consequences of treatment or care including such items as investigations, therapy, rehabilitation, pro rata wages and salaries of those professionals involved and other similar items.
46
Disability
Reduced capacity of a person to perform usual functions, usually the consequence of an IMPAIRMENT, such as impaired mobility or intellectual impairment. May cause HANDICAP.
47
Disability-adjusted life years (DALYs)
A population-based measure of the burden of disease and injury expressed in terms of hypothetical healthy life years that are lost as a result of specified diseases and injuries. DALYs comprise lifetimes lost completely because of death and health life years “lost” from onsets of nonfatal diseases and injuries, weighted to equivalent years completely lost (e.g., 2 years in a state half as bad as death has a “disability weight” of 0.5).
48
Discounting
An adjustment to cost estimates to allow for the fact that future monetary units (dollars, pounds, Euros, etc.) will have a different value from those at present, usually a smaller value because of the effects of inflation.
49
Early detection
A phrase describing prompt identification of incipient or early disease and, by implication, intervention to arrest, treat, and cure it in a timely manner. Methods of early detection include questionnaires, interviews, physical examinations, SCREENING tests. Early detection is an important role of primary care physicians, who can use many opportunities that arise in the course of incidental and continuing care of patients to conduct simple screening tests for early evidence of serious conditions, such as cardiovascular disease, diabetes, and cancer.
50
Early neo-natal mortality rate
The number of infant deaths in the first week of life per 1000 live and still births.
51
Effectiveness
The effect of a drug (or other intervention) in “the real world” (i.e. taking into account factors such as non-compliance (non-adherence))
52
Efficacy
The ability of a drug (or other intervention) to produce a therapeutic effect under circumstances close to “the ideal” (i.e. only looking at the effect in people who are thought to be taking the drug at the prescribed dose).
53
Efficiency
1. The end results achieved in relation to expenditure of money, resources, effort, and time that have been aimed at achieving these results. This is a measure of the economy or resource costs in relation to the output or end results of an intervention. In HEALTH ECONOMICS, several categories of efficiency are recognized, including: ALLOCATIVE EFFICIENCY, concerned with resource allocation; PRODUCTIVE EFFICIENCY, concerned with identifying the best way to produce desired health outcomes; and TECHNICAL EFFICENCY, concerned with the suitability and quality of equipment, facilities, etc.
54
Endemic
Refers to the constant presence in a population of a condition such as a communicable disease.
55
Environmental health
The branch of public health science and practice concerned with the whole range of environmental determinants of health, i.e., the physical, chemical, biological, social and behavioral factors in the environment that influence health and disease occurrence, and with diseases of environmental and occupational origin.
56
Epidemic
The occurrence in a community or specified population of deaths or cases of a condition in numbers greater than usual expectation for a given period of time.
57
Epidemiology
The study of the distribution and determinants of health related states and events in specified populations and the application of this study to the control of health problems
58
Equity
Fairness, even-handedness, impartiality in dealing with others; an important concept in bioethics especially in relation to human rights. An important consideration in relation to the availability of health care.
59
Evaluation
Efforts aimed at determining as systematically and objectively as possible the EFFECTIVENESS and impact of health-related (and other) activities in relation to objectives and taking into account the resources and facilities that have been deployed in the activities being evaluated.
60
Evidence based clinical effectiveness
Consistent use of best available evidence, preferably from current peer-reviewed sources in electronic and print media, to inform decisions about optimum patient management; decisions should consider the needs and preferences of individual patients. This evidence comes from many sources, for example, reports from the COCHRANE COLLABORATION.
61
Expectation of life
Syn: life expectancy. The average number of years an individual of given age can be expected to live if current mortality rates continue to apply.
62
Fetal death
Syn: STILLBIRTH. Death that occurs before complete expulsion form the uterus of a fetus or the product of conception at any time during the pregnancy after the gestational stage when the fetus is normally considered to be viable. This is variously defined as after the 20th or the 28th week of gestation.
63
Fetal death rate (Syn. stillbirth rate)
A vital record registering a fetal death, or stillbirth. Some health jurisdictions require the use of a fetal death certificate for all products of conception, whereas others require its use only in cases in which gestation has reached a particular duration, usually the 20th or the 24th week.
64
Fixed costs
The component of costs in the balance sheets or financial statements, e.g., of a health department, that remain unchanged over a defined, relatively long period; fixed costs include overhead-costs of lighting, indoor climate control, rental of buildings and equipment, and core staff-although these may be separately itemized in budgets and balance sheets.
65
General fertility rate
A measure of the fertility of a population using the annual number of live births as the numerator and the number of women in the reproductive age group (15-44 or 15-45 years) as the denominator.
66
Gold standard
A slang or jargon term for a measurement, test, method, or procedure that is considered to be the best available.
67
Hazard
The word means “risk”. In public health and epidemiology, it is often a synonym for RISK FACTOR, meaning the inherent capability of an agent or a situation to have an adverse effect, that is, a factor or exposure capable of adversely affecting health or causing harm or injury.
68
Hazard rate
Syn: force of morbidity, instantaneous incidence rate. A theoretical measure of the risk that a specified event will occur at a particular point in time.
69
Hazard ratio
A ratio of two hazard rates. Similar to a RELATIVE RISK or RATE RATIO.
70
Health outcomes
In evaluating the performance of health services, it is best to make use of objective indicators. Several of these are alliteratively identified as death, disease, disability, discomfort, disruption, and dissatisfaction. Death and disease are measured by mortality and morbidity rates, disability by means of the ADL or equivalent scales, discomfort by the amount of medication required to obtain relief of symptoms, disruption by the extent to which health problems impair capacity to engage in normal work and social activities, and dissatisfaction by such indirect unobtrusive measures as broken appointments, requests to change health care providers, surveys of patient satisfaction, and various others.
71
Health promotion
The policies and processes that enable people to increase control over and improve their health. These address the needs of the population as a whole in the context of their daily lives, rather than focusing on people at risk for specific diseases, and are directed toward action on the determinants or cause of health
72
Health protection
A term to describe important activities of public health departments, specifically in food hygiene, water purification, environmental sanitation, drug safety, and other activities in which the emphasis is on actions that can be taken to eliminate as far as possible the risk of adverse consequences for health attributable to environmental hazards, unsafe or impure food, water, drugs, etc.
73
Health technology
Any method used by health professionals to promote health, prevent and treat disease, or improve rehabilitation and long-term care
74
Health technology assessment (HTA)
Evaluation of the benefits and costs (clinical, social, economic and system-wide) of translating technology into clinical practice
75
Health-adjusted life expectancy (HALE)
Life expectancy expressed in QUALITY-ADJUSTED LIFE YEARS (QALYs). This is a way to take into account the effect on life expectancy of chronic disease and disability; which as a general rule can be expected to shorten life.
76
Health-related quality of life
A health status indicator that provides a proxy measurement of the UTILITY or value of a particular health state. Like utility, it is usually measured on a scale from zero to one, and assessed in conjunction with self-perceived or observed physical, social, and emotional function of individuals. In practice it is assessed by questionnaire or interview, using a rating scale if possible, rather than open-ended questions.
77
Iatrogenic disease
Disease resulting from the actions of a physician or other health professional. This usually means conditions specifically caused by following medical advice, using prescribed medications, or surgical interventions, or other medical mishaps and misadventures.
78
ICD number
The code number that identifies a specific diagnostic entity in the INTERNATIONAL CLASSIFICATION OF DISEASES. The level of precision in identification increases with the number of digits coded to identify a condition.
79
Iceberg phenomenon
A common situation in clinical practice, where only a small proportion of cases of important diseases, the tip of the iceberg, are seen at an early stage in the natural history when intervention can achieve prevention, care, or relief of symptoms.
80
Immediate cause of death
The first (sometimes the only) cause of death entered in Part I of a death certificate. The cause regarded as precipitating the death contrasted (in most cases) to the UNDERLYING CAUSE OF DEATH which started the sequence which, ultimately, led to that death.
81
Impairment
A physical or mental defect of function or structure that usually, but not necessarily always, leads to a DISABILITY and sometimes to a HANDICAP.
82
Impact assessment
Formal study of a public health intervention that usually focuses on the intermediate objectives in the continuum of process, impact, and outcome. Impact measures are usually short term and process oriented, such as immunization coverage rates linked to an intervention like a vaccination programme and that logically precede long-term outcomes such as reduced incidence rates of vaccine-preventable disease.
83
Income elasticity
The capacity of personal income to adjust to financial demands, distinguishing between necessities (shelter, food, clothing, etc.) and luxuries or discretionary spending.
84
Indirect cost
1. Syn: overhead costs. The cost of administration, buildings and maintenance, rental of premises, heat, light, water, etc. 2. In disease costing, the losses in production, well-being, etc., imposed by the occurrence of disease or injury, as distinct from direct treatment costs.
85
Inequalities in health
Syn: health disparities, gap. The differences in levels of health indicators associated with and often correlated with inequalities of socioeconomic levels. These inequalities are related to the effects of educational, housing, environmental and occupational factors, gender, and ethnicity, and to behavioral factors, such as differences in exposure to cigarette smoking and other risk factors. See also SOCIAL CLASS and SOCIOECONOMIC STATUS.
86
Infant mortality rate (IMR)
A measure of the mortality of children in the first year of life. The denominator is live births. Usually expressed per 1000 live births.
87
Interval cancer
A cancer that develops after a cancer screening test, such as a PAP SMEAR or a mammography examination, and before the next scheduled screening or physical examination.
88
Inverse care law
The availability of good medical care tends to vary inversely with the needs of the population served. This inverse care law operates more completely where medical care is most exposed to market forces, and less so where such exposure is reduced.
89
Intrauterine growth retardation
A condition in which fetal development proceeds more slowly than normal. Frequently associated with maternal malnutrition, maternal disease or placental abnormality. Defined as a birth weight less than the 10th percentile for a given gestational age. Associated also with an increased risk of certain conditions (such as hypertension and type 2 diabetes) in later adult life
90
Life expectancy
Syn: expectation of life. The average number of years a person of specified age and sex is expected to live if current trends in mortality rates prevail
91
Market
A physical or conceptual setting where goods and/or services are negotiated and traded. Markets can have advantages for consumers who can seek the best available price but can have disadvantages such as protectionist policies, trade secrets, and monopolies.
92
Marginal cost
The cost of the additional input needed to produce an additional unit of output. Marginal cost can differ from average cost. E.g. if it costs £100 to produce 100 units of output but £102 to produce 101 units (because an extra piece of equipment is needed to increase production beyond 100), the average cost per unit is £1.02, but the marginal cost of the 101st unit is £2.
93
Markov process
A stochastic process in which the conditional probability distribution at any future time is independent of the current state of the process. In epidemiology, it helps predict the course of pathogen transmission.
94
Maternal mortality
Syn: maternal death. Death of a woman while she is pregnant or within 42 days of the termination of a pregnancy, regardless of the duration of the pregnancy and its mode of termination. For classification purposes, maternal death is further divided into: 1. Late maternal death, i.e., death of a woman from direct or indirect obstetric causes more than 42 days but less than 1 year after the termination of the pregnancy. 2. A pregnancy-related death is death of a woman while she is pregnant or within 42 days of the termination of pregnancy irrespective of the cause of death. 3. A direct obstetric death is death due to obstetric complications of pregnancy. 4. An indirect obstetric death is death resulting from a cause that existed before the pregnancy and is not aggravated by the physiological effects of the pregnancy.
95
Maternal mortality ratio (MMR)
The risk of dying of puerperal causes, i.e., associated with pregnancy, labor, childbirth, or the postpartum period, expressed as a ratio per 100,000 births, or less often as a “rate” per 100,000 women of reproductive age. Puerperal causes are mostly clearly defined, although the postpartum period is not. For statistical purposes, the WHO defines “postpartum” as any time up to and including 42 days after the termination of pregnancy, regardless of the duration of the pregnancy. The denominator is the number of live births in the same period in the same administrative or statistical jurisdiction.
96
Millennium Development Goals
A set of eight goals adopted at the Un Millennium Summit in September 2000 to alleviate conditions for more than a billion people in the world who were living in extreme poverty. Several of these goals have implications for public health, and four have explicit health targets: 1. Eradicate extreme poverty and hunger; 4. Reduce child mortality and achieve a two-thirds reduction in mortality in those younger than 5 years, by 2015; 5. Improve maternal health and reduce by three-quarters the maternal mortality ratio, by 2015; 6. Combat HIV/AIDS, malaria, and other lethal diseases, including halting and reversing incidence and death rates from HIV/AIDS, malaria, and other lethal diseases, including tuberculosis.
97
Needs assessment
A formal process conducted by health and social workers and others in health agencies to delineate the dimensions and severity of health and social problems of people, families, and specified communities, especially those considered to be at high risk, so that resources can be deployed to manage them efficiently.
98
Neonatal mortality rate
The number of deaths in infants under 28 days of age per 1000 live births.
99
Net fertility rate
The average number of daughters that would be born to a birth cohort of women during their lifetime if they experienced a fixed pattern of age-specific fertility and mortality rates.
100
Noncompliance
Failure to adhere to or abide by the recommendations or instructions of health care professionals, such as failure to take prescribed medication or adhere to a dietary regimen.
101
Number needed to harm
The number of patients who need tot receive a specified medication to cause a specified ADVERSE OUTCOME in a patient.
102
Number needed to screen
The number of people who must be given a SCREENING procedure to detect a case of the specified condition for which the screening procedure is conducted.
103
Number needed to treat
The number of patients who must be treated in order for a specified outcome to occur. Such outcomes may be the prevention of a case of the disease of interest e.g. a myocardial infarction or a stroke in the case of treatment with an antihypertensive or a cholesterol lowering drug. Calculated as the reciprocal (the inverse or one divided by) the ABSOLUTE RISK REDUCTION.
104
Opportunity cost
The value of goods or services that could have been obtained for the same cost as that which has been expended on the provision of the specific goods/services for which the opportunity cost is being computed.
105
Outcome measures
Quantifiable consequences of an action, set of actions, or procedure. In the health field, many outcome measures are used to assess and evaluate aspects of health care.
106
Perinatal mortality
Deaths between 24 weeks (sometimes 22 weeks) gestation and one week postnatal expressed per 1000 live and still births.
107
Placebo
An inert preparation with no pharmacological effect that is used for comparison with an active regimen in a CLINICAL TRIAL to study the outcome of interventions with an experimental drug or innovative regimen. Placebos may have a “PLACEBO EFFECT”. ,
108
Placebo effect
A physiological or emotional action attributable to the power of suggestion, seen in the control or comparison group in a CLINICAL TRIAL if this group is treated with a PLACEBO.
109
Population at risk
In epidemiological studies, the group of people that can be defined in numbers in which the occurrence of specified events is studied.
110
Population attributable risk (PAR)
The incidence of a disease in a population that is associated with (attributable to) exposure to the risk factor. It is often expressed as a percentage.
111
Postneonatal mortality rate
The number of infant deaths between 28 days and 1 year of age per 1000 live births.
112
Potential years of life lost (PYLL)
A measure of the relative impact of various diseases and lethal forces on society. The PYLL is computed for specific causes of death by summing the expected years of life remaining (according to a reference table) for each individual age at death for the cause of interest. The effect is greatest for causes operating strongly at young ages, such as AIDS, fatal vehicular injuries, and homicides in young black males in the United States.
113
Primary prevention
Strategies, tactics, and procedures that prevent the occurrence of disease. Examples include provision of safe drinking water; sanitation and hygiene; the use of immunizations or vaccinations that confer immunity against certain communicable diseases; and mass medication, such as use of iodized salt to prevent the occurrence of cretinism and goiter in iodine-deficient regions.
114
Primordial prevention
Strategies and tactics that eliminate exposure to significant risk factors of disease, e.g., genetic counselling to avoid unions of partners carrying lethal recessive genes.
115
Prion
Infectious proteinaceous particle, protein molecules that have some of the properties of viruses and are the agents of several deadly forms of transmissible spongiform encephalopathies, including bovine spongiform encephalopathy (BSE), and Creutzfeldt-Jakob Disease.
116
Protective factor
A factor the presence of which reduces the likelihood that a particular disease or adverse health outcome will occur. The opposite of RISK FACTOR.
117
Qualitative analysis
Analysis that relies on descriptive accounts of behaviour, belief s, feelings, or values, with few or no numerical data available for statistical analysis.
118
Quality adjusted life years (QALY)
An adjustment of life expectancy that reduces the overall life expectancy by amounts that reflect the existence of chronic conditions causing impairment, disability, and/or handicap as assessed from health survey data, hospital discharge data, etc.
119
Quality of life (QOL)
An essentially subjective judgement of the way people perceive themselves as contented and happy or otherwise, and able to function physically, emotionally and socially. Others, including health workers, can make a relatively objective judgement of some of these aspects of a person’s way of living, but the affected individual is the ultimate judge.
120
Registrar General’s Occupational Classification
An occupational classification that categorized employed people into five “social classes”, conventionally designated by Roman numerals I to V. Class I is professional occupations, typically requiring university-level education, such as physicians, lawyers, ministers of religion, etc.; Class II is described as intermediate professional and managerial occupations, such as bank managers and school teachers; Class III, skilled workers, is divided into skilled clerical and skilled manual workers; Class IV is semiskilled workers, such as bank clerks, farm labourers, and factory assembly line workers; and Class V is unskilled workers, e.g., shop assistants and food servers in fast food establishments. This classification, first used in the 1911 census, was routinely used until the 1980s and remains a useful tool for many sociological, epidemiological, and economic analyses. Social class correlates closely with many causes of death, disease, and disability. See also SOCIOECONOMIC CLASSIFICATIONS.
121
Resource allocation
The process of deciding how to distribute limited quantities of goods and service, numbers of qualified staff, specialized facilities, and available funds among competing claims for them. Ideally, it is evidence based, with supporting data from demographic, epidemiological, sociological, and economic sources and takes due account of ethical and political concerns.
122
Screening
A public health intervention in which members of a defined population, who do not necessarily perceive they are at risk of, or who do not necessarily perceive that they are already affected by, a disease or its complications, are asked a question or offered a test to identify those individuals who are more likely to be helped than harmed by further tests or treatment to reduce the risk of disease or its complications.
123
Socioeconomic status (SES)
The proportion of those who do not have the disease that the test correctly identifies as not having it or the probability of correctly identifying the fact that a person does not have the disease using the test.
124
Sufficient cause
An agent, event, condition or characteristic which, on its own, is enough to produce an occurrence of a disease, condition or health-related state. There are very few real examples. Even infection with a given agent (such as the measles virus) may not be deemed sufficient since this has to be infection of a susceptible host.
125
Surveillance
Symstematic, ongoing collection, collation, and analysis of health-related information that is communicated in a timely manner to all who need to know which health problems require action in their community. Surveillance is a central feature of epidemiological practice, where it is used to control disease. Information that is used for surveillance comes from many sources, including reported cases of communicable diseases, hospital admissions, laboratory reports, cancer registries, population surveys, reports of sickness absence from school or work (in which a sudden sharp rise in numbers may signal the onset of an epidemic), and reported causes of death, in which again a sudden rise in numbers, for instance of deaths from pneumonia, may signal the onset of epidemic influenza.
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Tertiary prevention
Distinguished from PRIMARY and SECONDARY prevention and referring to the prevention of the worsening of an already established condition e.g. through treatment or rehabilitation.
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Time series
Any sequential measurements continued over a period that aim to reveal changing trends over time.
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Total fertility rate
The average number of children a woman would bear if all women live to the end of their childbearing years and have children according to a given set of age-specific fertility rates. It is the sum of age-specific fertility rates multiplied by the number of years in each age interval, typically 5.
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Townsend score
In full: the Townsend Material Deprivation Score. An index of the social and economic deprivation of a locality, such as an administratively defined region in a city. It is based on the composite score for four proportions: unemployed residents older than 16 years, as a percentage of all economically active residents aged older than 16 years; proportion of households in the area with 1 person per room and over; proportion of households with no car; and proportion of households not owning their own home. It is used in the census and in population surveys in the United Kingdom. Similar to the CARSTAIRS INDEX.
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Under 5 mortality rate
The estimated probability of dying between birth and the fifth birthday, in life table notation 5q0. It is usually expressed as the ratio of deaths in those younger than 5 years to 1,000 live births and is regarded as one of the most useful and sensitive indicators of child health in low- and middle-income countries, where it may not be practicable to calculate infant mortality rates for the whole population. Instead, the under 5 mortality rate is estimated from responses of women in reproductive ages to questions in a DEMOGRAPHIC AND HEALTH SURVEY about the number of children they have borne and the number still alive. The rate can be directly estimated if detailed birth histories are available or indirectly estimated if only summary information is available.
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Underlying cause of death
The disease, injury, or pathological condition that initiates the chain of events leading to death. The attending physician or other individual responsible for writing the death certificate attributes the death ultimately to this condition, and this is used in the compiled statistical tables of causes of death.
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Utility
In economics, a synonym for individual welfare or well-being. Health economists use the term to mean the value of a specified health state, often expressed on a scale from 0 – 1, and use it to determine QUALITY-ADJUSTED LIFE YEARS (QALYs) and HEALTH-ADJUSTED LIFE EXPECTANCY (HALE). Utility is based on preferences that individuals express about alternative outcomes likely to follow their treatment choices.
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Waist-to-hip circumference ratio
An indicator of obesity when waist circumference exceeds hip circumference, also known as “upper body obesity”, this is a useful prognostic indicator of future morbidity and mortality from coronary heard disease, stroke, and non-insulin-dependent diabetes. Recent studies have indicated that it is a better indicator than body mass index.
