Canadian Environmental Health Atlas

Understanding Our Environment is Key to Promoting Health and Preventing Disease

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Glossary of Terms

Glossary of Terms

age-standardized mortality rate (ASMR): A death rate for a defined population that has been standardized to remove the confounding effects of differences in age and other factors as much as possible, so that two or more populations can be compared.

ambient air quality: The quality of outdoor air, typically measured near ground level and away from direct sources of pollution.

biomarker: A cellular, biochemical, or molecular indicator of a particular biological condition or process. These indicators can be measured accurately, and are often characterized as biomarkers of exposure, effect, or susceptibility.

biomarker of effect: A biochemical, physiological, behavioural, or other alteration in an organism associated with an established or potential health effect caused by exposure to a chemical, physical, or infectious agent (e.g. blood cholinesterase levels following organophosphate pesticide exposures).

biomarker of exposure: A chemical or its metabolite(s) not normally found in an organism that can be measured to determine the level of exposure to the chemical (e.g. lead detected in a  blood sample).

biomarker of susceptibility: A physiological or biochemical indicator of a natural characteristic that may make an organism more likely to be affected by a chemical, physical, or infectious agent (e.g. genetic factors).

bivariate regression analysis: A statistical method used to compare a continuous dependent variable with an independent variable. When the data compared are depicted on a graph as a regression line, the independent variable is plotted on the x-axis and the dependent variable is plotted on the y-axis.

case-fatality rate: The proportion of cases of a specified condition that are fatal within a specified time. Usually expressed as a percentage.

Canadian Community Health Survey (CCHS): A cross-sectional survey conducted to collect information related to regional health status, health care utilization, and health determinants. A joint effort of Health Canada, the Public Health Agency of Canada, Statistics Canada, and the Canadian Institute for Health Information (CIHI). The two kinds of surveys undertaken to date focus on the general health of Canadians and on specific health topics.

Canadian Health Measures Survey (CHMS): A national survey conducted by Statistics Canada to collect information from Canadians about their general health and lifestyles. Data are obtained by interviewing volunteer respondents at home and by taking direct physical measurements (e.g. blood pressure) and collecting urine and blood samples at mobile clinics. 

cohort study: The study of subsets of a defined population. In an epidemiological study, some subjects might be exposed, or exposed in different degrees, to a factor (e.g. an environmental contaminant) hypothesized to influence a given outcome (e.g. a disease). Usually large numbers of subjects are observed over a long period (commonly years),  which permits a comparison of incidence rates in groups with different degrees of exposure.

Community Well-Being (CWB) Index: Used by Aboriginal and Northern Affairs Canada to measure the socioeconomic well-being of individual Canadian communities using various indicators, including education, labour force activity, income, and housing. Data from Statistics Canada’s Census of Population are combined to give each community a well-being score. These scores are then used to compare the well-being of First Nations and Inuit communities with other Canadian communities over time.

country foods: Edible plants, berries, mammals, fish, and waterfowl harvested from the local environment. These foods play a critical role in the social, cultural, spiritual, economic, and nutritional well-being in many Aboriginal communities.

cryptococcosis: A potentially fatal disease caused by fungi that belong to the genus Cryptococcus. One of the disease-causing species, Cryptococcus gattii, was previously found only in tropical and subtropical areas, but is now found in more temperate regions.

ecological fallacy: An erroneous inference about an individual based on study findings for a group, which can occur because an association observed between variables on an aggregate level does not necessarily mean the association exists on an individual level.

ecological niche model: A model to predict the geographic distribution of a species, developed using a computer algorithm and data about the environment, including climate, soil type, and vegetation.

ecological study: In epidemiology, a study in which the units of analysis are populations or groups rather than individuals.

endemic disease: The constant presence of a disease or infectious agent within a given geographic area or population. May also refer to the usual prevalence of a given disease within such an area or group.

endogenous: Having an internal cause or origin.

environmental sampling: The process of selecting a number of subjects from among all the subjects in a particular environment.

emerging infectious disease: A disease that (1) has not occurred in humans before (a type of emergence difficult to establish and probably rare), or (2) has occurred previously but affected only small numbers of people in isolated places (e.g. AIDS, Ebola hemorrhagic fever), or (3) has occurred throughout human history but has only recently been recognized as a distinct disease caused by an infectious agent (e.g. Lyme disease, gastric ulcers).

emissions: A flow of gases, liquid droplets, or solid particles released into the air through natural processes or human activities.

Environmental Protection Agency (EPA): An independent federal agency in the US that sets and enforces rules and standards to protect the environment and control pollution.

epidemiology: The study of health-related states or events in defined populations, including the study of the determinants influencing such states, and the application of this knowledge to promote well-being.

exceedance: In the US, a measured level of an air pollutant higher than the National Ambient Air Quality Standards (NAAQS) set by the Environmental Protection Agency (EPA). The violation of a national ambient air quality standard is based on years of data, so monitoring an exceedance does not necessarily mean that a violation of the standard has occurred.

excess deaths: Deaths  that occur before the age of average life expectancy for people of a particular demographic category.

exogenous: Having an external cause or origin.

genotype: The genetic constitution inherited by an organism, as distinct from the physical characteristics and appearance that emerge with development or modulation by the environment (i.e. the phenotype).

geographic information system (GIS): A computer system for storing and manipulating geographical information.

incidence: The number of  new health-related events (e.g. people falling ill with a disease) in a defined population during a specified period. Incidence may be measured as a frequency count, a rate, or a proportion.

incubation period: The time between invasion of an organism by an infectious agent and the appearance of the first sign or symptom of the disease caused by the agent.

index case: The first case of a disease or condition in a family or other group to come to the attention of an investigator.

infant mortality rate: The death rate for infants who die in the first year of life, expressed as the number of deaths per 1000 live births. A long-established measure of the well-being of a society, including the health care available, the effectiveness of preventive care, and the attention paid to maternal and child health.

infectivity: 1. The characteristics of a disease agent that allow it to enter, survive, and multiply in a host. 2. The proportion of exposures resulting in infection.

land use regression (LUR): A method employed to measure and predict air pollution concentrations by considering land use, traffic, and aspects of the physical environment at a given site.

latency period: The time between exposure to a disease-causing substance or agent and disease manifestation.

life expectancy: A hypothetical measure expressed as the average number of years an individual of a given age is expected to live if current mortality rates continue to apply.

low birth weight: A birth weight of less than 2500 g, expressed as a percentage of all live births with known birth weights. Low birth weight is a key determinant of infant survival, health, and development.

market foods: Foods purchased from grocery stores and other retail outlets.

National Ambient Air Quality Standards (NAAQS): In the US, a level of outdoor air quality set by the Environmental Protection Agency (EPA) to protect human health and public welfare. Standards have been set for six common pollutants: carbon monoxide, lead, nitrogen dioxide, particulate matter, ozone, and sulfur dioxide.

nitrogen dioxide (NO2): One of a group of highly reactive gasses known as oxides of nitrogen. NO2 forms quickly from emissions from vehicles and power plants, and contributes to the formation of ground-level ozone and fine particle pollution. NO2 is linked with a number of adverse effects on the respiratory system.

nosocomial: Used to describe a disease arising while a patient is in a hospital or as a result of being in a hospital. Denotes a new disorder unrelated to the patient’s original reason for admission to hospital.

outbreak: An increase in the incidence of a disease that is limited to an institution, a neighbourhood, or a small community.

particulate matter: A complex mix of extremely small particles and liquid droplets. Particle pollution may include acids (e.g. nitrates, sulfates), organic chemicals, metals, and soil or dust particles. The size of particles is directly linked to their potential for causing health problems.

pathogen:Any virus, microorganism, or substance capable of causing disease.

PM2.5:Particulate matter that is 2.5 micrometers in diameter—one-thirtieth the diameter of a human hair—and smaller. Fine particle pollution can be emitted directly or formed in the atmosphere.

pollutant:Any undesired contaminant in solid, liquid, or gaseous form that pollutes an environment.

relative risk: 1. The ratio of the risk of an event among those exposed to a risk factor to the risk among those not exposed (i.e., the risk ratio). 2. The ratio of the incidence rate in the exposed to the incidence rate in the unexposed (i.e., the rate ratio).

retrospective chart review: A study that uses data from medical records, often called charts, which have been recorded for reasons other than research.

simulation: The use of a model (e.g. a mathematical model or an animal model) to approximate the functioning of a real system and allow investigators to study the properties and action of that system.

socioeconomic status (SES): A measure of a person’s sociological and economic position in society, based on income, occupation, and education.

sulpher Dioxide (SO2): One of a group of highly reactive gasses known as oxides of sulfur. SO2 emissions come primarily from fossil fuel combustion at power plants and other industrial facilities. SO2 is also emitted at facilities extracting metal from ore and when high-sulfur fuels are burned by locomotives and large ships. SO2 is linked with a number of adverse effects on the respiratory system.

survivor effect: A distortion in the analysis of an effect when a study of a disease or health-harming event includes only survivors and excludes those who have succumbed to the disease or event.

time series: A study based on a sequence of measurements or observations made at several different times in order to detect trends. An interrupted time series features several measurements or observations, both before and after an intervention, which can make the findings more valid than those obtained from a study with a simple pretest-posttest design.

well-being: A state of being happy and healthy.