GLOSSARY
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
A
- ACGIH:
- Abbreviation for American Conference of Governmental Industrial Hygienists.
- Air monitoring:
- Air monitoring means monitoring of the concentrations of airborne hazardous chemical substances.
- Approved inspection authority:
- Defined in the Occupational Safety Act: An inspection authority approved
by the chief inspector: Provided that an inspection authority approved by the
chief inspector with respect to any particular service shall be an approved
inspection authority with respect to that service only.
- Association:
- The relationship between two or more events, characteristics, or other
variables, often quantified in statistical terms. Synonyms are correlation,
statistical dependence and relationship. A (numerical) relationship between
2 or more events, characteristics, or other variables.
- Attenuation:
- Attenuation means the proven capability of hearing protectors to reduce the equivalent noise
level to which the wearer thereof is exposed.
-
B
- BEI:
- Abbreviation for Biological Exposure Index. The Biological Exposure Index (BEI)
is a reference value intended as a guideline for the evaluation of potential health
hazards.
- Bias:
- A systematic deviation from the truth. Any trend in the collection,
analysis, interpretation, publication, or review of data that can lead
to conclusions that are systematically different from the truth. We
understand bias as either selection or information bias. See
confounding.
Selection bias. This occurs where there are systematic differences in
characteristics between those in the population selected for study and
those that are not. Information bias. This occurs where there are systematic
]errors in measurement, recording, management, analysis or reporting of
data. Most often, information bias is an error due to different quality
or accuracy of information between groups compared. It refers to measurement
of exposure or of effect.
C
- Confounding:
- This occurs where the effects of two concurrent or simultaneous processes
in causing an outcome are not explicitly separated. (Risk factor 1 seemingly
causes an outcome, but in reality another risk factor 2 is mixed-in with
risk factor 1 and distorts the apparent contribution of risk factor 1, by
having an impact on the outcome.) See bias.
D
- Danger:
- A danger is anything which may cause injury to persons or damage to property.
- dB(A):
- dB(A) is the unit of measurement of sound pressure level.
- Denominator:
- The lower portion of a fraction. Epidemiologists use fractions to calculate rates,
or ratios. The denominator is usually the population at risk, although it
may also be a measure, such as person-time, that quantifies the population's
exposure.
- Disability/Disablement:
- The term "disability" refers to an impairment, which prevents the person
from accomplishing certain tasks, or from performing an occupation, thereby
impacting on his/her ability to live a normal life, or to earn an income.
- Distribution:
- The complete summary of the frequency and pattern of the values or categories
of a measurement. In epidemiology, distribution is the frequency and pattern
of health-related characteristics and events in a population. Classically
described in terms of time place and person/ population.
- E
- Employee Assistance Programme (EAP):
- This is the delivery of support services for employees that are functioning
sub-optimally due to physical, psychological and social problems, and
include counselling, training, rehabilitation, and the mobilisation of
statutory bodies where necessary.
- Employee Benefits & Curative Care:
- This includes matters such as pension or provident fund provision, statutory
entitlements, such as sick leave, perinatal leave, medical aid, hospital
insurance and other negotiated benefits.
- Engineering control measures:
- Engineering control measures are control measures that remove or reduce exposure of persons at the
workplace by means of engineering measures.
-
- Epidemic:
- The occurrence of more cases of a particular type of disease, chronic condition,
or injury than expected in a given area, or among a specific group of people,
over a particular period of time. (Think miles, many people, and months).
An Outbreak is a confined epidemic, in time, place, and population. In the
public's mind, "epidemic" has a far more serious connotation than "outbreak."
A Pandemic is an epidemic occurring over a very wide area (several countries
or continents) and usually affecting a large proportion of the population.
An endemic health condition is a disease, chronic condition, or type of injury
that is constantly present in a given geographic area or group.
- Epidemiology:
- The study of the distribution and determinants of health conditions or events
in populations, and the application of this study to control health problems.
The study of disease occurrence and causes in human populations. Occupational
epidemiology is the study of the distribution and determinants of health in
working humans. ( Analytic Epidemiology. The aspect of epidemiology concerned
with why and how a health problem occurs. Analytic epidemiology uses comparison
groups to provide baseline data so that associations between exposures outcomes
can be quantified and hypotheses about the cause of the problem can be tested.
(Descriptive epidemiology. The aspect of epidemiology concerned with gathering,
organizing, and summarizing data on "person" (Who is ill?), "time" (When did
they become ill?), and "place" (Where could they have been exposed to the illness?).
This information is then used to conduct analytic epidemiology.
- Evaluation:
- Systematic and objective examination of activities to determine how relevant
and effective they are.
F
- Fit for work:
- The term "medically fit for work" means that the person has been medically
assessed and found to be suitable for the occupation’s Occupational Risk
Exposure Profile (OREP), and that the person meets the relevant medical
requirements, as recorded in the linked Worker Allocated Surveillance
Programme (WASP).
G
H
- Hazard:
- A physical, chemical, biological, ergonomic or psychosocial agent that can
cause disease or ill-health. Related words are: ( Agent. A factor that is essential
for a disease, chronic conditions, or injury to occur. In occupational health
we divide classify these into the five hazard classes. In theory, agents can
cause a health problem by being introduced, being present in excess, or being
present at deficient levels. ( Determinant. Any factor that brings about change
in a health condition or in other defined characteristics. ( Environmental
factor. An extrinsic factor, such as geology, climate, insects, sanitation,
or health services, which affect an agent and the opportunity for exposure.
( Exposure. Coming into contact with a cause of, or possessing a characteristic
that is a determinant of, a particular health problem. ( Exposed group. A
group whose members have had contact with a cause of, or possess a characteristic
that is a determinant of, a particular health problem. ( Host factor. An
intrinsic factor (e.g., age, race, sex, behaviours) that influences an
individual's exposure, susceptibility, or response to an agent. ( Risk
factor. An aspect of personal behaviour or lifestyle, an environmental
exposure, or a hereditary characteristic that is associated with an increase
in the occurrence of a particular disease, chronic condition, or injury.
A protective factor is one which decreases the occurrence of the outcome.
- Hazardous Chemical Substance (HCS):
- Hazardous chemical substance is any toxic, harmful, corrosive, irritant or
asphyxiant substance, or a mixture of such substances for which an occupational
exposure limit is prescribed or which creates a hazard to health.
- Health:
- A state of complete physical, mental, and social well-being and not merely
the absence of disease or other infirmity. Health indicator. Any of a variety
of measures (e.g., mortality rate) that indicates the state of health of people
in a defined population.
- Health Promotion and Wellness (HP&W) Programme:
- This is the term which describes the coordinated activities that aim for a
state of health that exceeds the absence of disease, and seeks to achieve
optimal mental, social and physical function.
- Hearing protectors:
- Hearing protectors are ear muffs or earplugs of a type approved by the Chief Inspector.
- Hygiene:
- The principles and practice of maintaining health. "Occupational Hygiene is
the discipline of anticipating, recognising, evaluating and controlling health
hazards in the working environment with the objective of protecting worker
health and well-being and safeguarding the community at large" (IOHA definition).
These hazards may be physical, chemical, biological, ergonomic or psychosocial,
and may cause injury, illness, impairment, or affect the well-being of workers
and members of the community.
I
- Impairment:
- The term "impairment" refers to any loss or abnormality of psychological
physiological or anatomical structure or function. I PREFER THIS : WHO
ICDIH definition of impairment -. link
- Incidence:
- A rate that measures the frequency with which a health problem, such as a
new injury or case of illness, occurs in a population.
Incidence proportion: The number of new cases occurring in a
population during a given period of time, divided by the total population at
risk during that time.
Incidence rate: The number of new cases occurring in a population,
divided by the person-time at risk.
- Illuminance:
- Illuminance is the intensity of light falling on a surface, measured in lux.
- Illuminance meter:
- An instrument used for measuring illuminance.
J
K
L
- Leq:
- Leq (equivalent noise level) is the value of the equivalent continuous sound
level which would deliver the same amount of sound energy as the actual fluctuating
sound, measured over the same time period.
- luminaire:
- A luminaire is a light fitting which supports a lamp and provides
it with electrical connections.
- lux:
- The lux, (lx) is the SI unit of illuminance.
- lux meter:
- An instrument used to measure the amount of light falling on a surface.
M
- Material Safety Data Sheets:
- Material Safety Data Sheets (MSDS) are documents used to convey information about safe use of substances to the user. MSDS
contains information on the identity, chemical and physical properties, potential health
effects, and precautions for the safe use and handling of substances.
- Medically unfit:
- The term "medically unfit" refers to the failure to meet the specific
inherent requirements of an occupation due to the presence of a medical
condition that is an exclusion for the relevant occupation, or due to a lack
in the capacity (physical or mental) to perform the work, to the required
standard.
- Mortality rate:
- A measure of the frequency of occurrence of death in a defined population during
a specified time interval. Mortality rates can be given as age-adjusted,
age-specific, cause-specific, or crude. The crude mortality rate is a population's
mortality rate from all causes of death.
N
- Natural history of disease:
- The course of a disease from the time it begins until it is resolved.
- Noise zone:
- A noise zone is an area where the equivalent noise level is equal to or exceeds 85 dB(A).
- Notifiable disease:
- A disease that, by law, must be reported to public health authorities upon
diagnosis. Lung cancer is one such disease in occupational health.
- Numerator:
- The upper portion of a fraction. Typically the number of people with disease.
O
- Occupational Health Nurse Practitioner:
- This means a registered nurse who holds a qualification in occupational
health, recognised as such by the South African Nursing Council as referred
to in the Nursing Act, 1978 (Act No. 50 of 1978).
- Occupational Health (OH) Programme:
- This is the science of work-related injury and illness prevention, incorporating
the disciplines of Occupational Hygiene, Safety and Medicine, through various
strategies, including risk assessment and risk control by means of engineering
away hazards, and monitoring for early signs of failure of these controls.
- Occupational Hygiene Assistant:
- This means a person with suitable training that will conduct the activities
required of an Occupational Hygiene Programme, under the supervision and
guidance of an Occupational Hygienist.
- Occupational Hygienist:
- This means a person who holds a qualification in occupational health recognised
as such by the South African Occupational Hygiene Association, and who
meets the requirements of an approved Inspection Authority, as prescribed
by South African Law.
- Occupational Medical Practitioner:
- This means a medical practitioner as defined in the Medical, Dental and
Supplementary Health Service Professions Act, 1974 (Act No. 56 of 1974),
who holds a qualification in occupational medicine or an equivalent qualification
which qualification or equivalent is recognised as such by the South
African Medical and Dental Council referred to in the said Act.
- Odds ratio:
- A measure of association used in comparative studies to quantify the relationship
between an exposure and a health outcome; also known as the cross-product
ratio.
- Occupational Exposure Limit:
- The Occupational Exposure Limit (OEL) is a limit value set by the Minister
of Labour for a stress factor in the workplace as revised from time to time
by notice in the Government Gazette.
- OEL-CL:
- Abbreviation for Occupational Exposure Limits - Control Limits.
- OEL-RL:
- Abbreviation for Occupational Exposure Limits - Recommended Limits.
- Occupational hygiene:
- Occupational hygiene means the anticipation, recognition, evaluation and
control of conditions arising in or from the workplace, which may cause
illness or adverse health effect to persons.
- Outcome, or disease, or disease outcome:
- Injury, illness, impairment, or changes in the well-being of workers. Any
or all of the possible results that may stem from exposure to a causal factor
or from preventive or therapeutic interventions. All identified changes in
health status that result from the handling of a health problem.
P
- Population:
- The total number of inhabitants of a given area or country. In sampling, the
population may refer to the units from which the sample is drawn, not necessarily
the total population of people. A population can be a particular group at risk,
such as everyone who is engaged in a certain occupation. A population need
not be human, eg. farms, households, folders. A group sharing certain common
characteristics, about whom inferences can be made.
- Prevalence:
- The number or proportion of cases or events or conditions in a given population,
as measured at a point in time, e.g. if measured now, the number or proportion
of people now who have diabetes.
- Primary Health Care (PHC) Programme:
- The Primary Health Care (PHC) Programme is the delivery of first-level medical interventions,
including curative as well as preventive, for injured and ill employees at
work, and is implied to be an on-site activity.
- Proportion:
- A ratio in which the numerator is included in the denominator; the ratio of
a part to the whole, expressed as a decimal fraction (e.g. 0.2), a fraction
(1/5), or a percentage (20%). It is a special ratio, where the value is between
0 and 1.
Q
R
- Rate:
- A ratio with an implicit time-element, often multiplied by 10n.
- Ratio:
- The value obtained by dividing any one quantity by another, e.g. female: male
ratio. Percentages, proportions and rates are all ratios.
- Respiratory protective equipment:
- Respiratory protective equipment is a device which is worn over at least the mouth and nose to
prevent the inhalation of air which is not safe.
- Risk:
- The probability that an individual will be affected by, or die from, an
illness or injury within a stated time or age span, or that serious damage to property
will occur.
S
- Sample:
- A selected subset of a population. A sample may be random or non-random and
representative or non-representative.
- STEL:
- Abbreviation for Short Term Exposure Limits.
- Study:
- An epidemiological study often compares two groups of people who are alike
except for one factor such as exposure to a chemical or the presence of a
health effect. The investigators try to determine if the factor is associated
with the health effect.
Analytic study: A study examining associations between groups, typically
looking for causality. The common types of analytic study are cross-sectional,
case-control and cohort studies.
Descriptive study:. A study describing the existing distribution
of variables, without regard to causal or other hypotheses. Classically, there
is no comparison group. Examples are case studies, case series, and descriptive
cross-sectional studies.
Interventional study: An analytical study where the investigators
systematically and intentionally change the exposure status of the subjects,
by e.g. giving therapy, or removing a risk factor.
Observational study:. An analytic epidemiologic study in which
there is no intervention. Changes or differences in one characteristic are studied
in relation to changes or differences in others.
Case-control study: An analytic observational study where cases
(with the disease or outcome) are compared with suitable controls (without
the disease or outcome), by looking at their (historical or current) exposures.
The starting point occurs after the onset of the disease or outcome, and
looks back to find postulated causal factors. It's like taking snapshots of
some sick and some healthy family members, and then paging through the family
album looking for previous snapshots of those same family members, looking
for clues as to why they got sick or not. A study in which people with a
disease (cases) are compared to people without the disease (controls) to see
if their past exposures to chemicals or other risk factors were different.
Cohort study: An analytic observational study where a well-defined
group of disease free people who have had a common experience or exposure
are followed up through time, looking for disease outcomes. The starting
point occurs before the onset of the disease or outcome, having already
identified postulated causal factors. It's like a number of snapshots taken
at periodically of all family members who could be present, looking for clues
as to why some got sick. A study in which a group of people with a past
exposure to chemicals or other risk factors are followed over time and their
disease experience compared to that of a group of people without the exposure.
Cross-sectional study: (Prevalence study.) A study that examines
the relationship between exposures and outcomes prevalent in a defined population,
at a defined point in time. The start and endpoint are the same, and disease
and postulated causal factors are measured simultaneously. It's like a single
snapshot of everyone in the family who could be gathered for the photo, looking
for clues as to why some are sick.
T
- Time Weighted Average:
- The time-weighted average (TWA) is the average of a number of representative
measurements that are taken over a period of time and that are calculated as follows:
TWA = (x1t1 + x2t2 + ... + xntn) /
(t1 + t2 + ... + tn)
where x1, x2, etc. are the observed measurements during corresponding
periods t1, t2, etc.
- TLV:
- Abbreviation for Threshold Limit Value.
- Two-by-two table:
- A table with 4 cells, which is the basic numerical method used to compare
occurrence of disease in different groups. The groups are simply divided
into those with and without exposure and those with and without disease.
The 4 cells are labeled a, b, c and d. Cell a contains those with both
exposure and disease, and cell d contains those free of both exposure and
disease.
U
V
- Variable:
- Any characteristic or attribute that can be measured and can have different values.
W
- Wet bulb globe temperature (WBGT):
- The wet bulb globe temperature (WBGT) index is a number which characterises the thermal conditions
in the environment to which that number applies.
X
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General Introduction to
Occupational Health: Occupational Hygiene, Epidemiology & Biostatistics by Prof Jonny Myers is licensed under a Creative Commons Attribution-Noncommercial-Share Alike
2.5 South Africa License.