help

help

case series study

researchers get info over time about patients that have the same disease (no control group)

cross sectional studies (or prevalence study)

observe association between disease & disease factors presence in the population of interest. distribution of disease and exposure are determined

ecological study

focused on populations, measures association between average exposure to air pollution within cencus tracts and average mortality in those census tracts

case-control study

subjects are arranged on the basis of presence or absence of a specific outcome or disease. matched according to specific criteria like age or ethnicity. these can provide more complete exposure data. precise exposure measurements and ability to identify unobserved confounding factors may be difficult. can only examine one or a few. association between exposure and disease is odds ratio

odds ratio

a measure of association for case control studies

cohort studies

Prospective - classify subject according to their exposure to a risk factor (observe over time to determine the occurrence of new cases

Retrospective - conducted by reconstructing data about persons at a time or times in the past (source of info, hospital records) able to evaluate many different health outcomes but few exposures

relative risk

association used in cohort studies. quantifies the strength of association between a particular risk factor or exposure and the incidence of a disease. morbidity, mortality, quality of life

experimental studies (intervention studies)

researchers design intentional changes in the behavior or exposure level of the subjects

prevalence

number of existing cases, health condition, or deaths in population at a certain time

incidence

fraction of a group initially free of a disease that go on to develop it during a given time period

case fatality rate

measures lethality of a disease

epidemiology triangle

explains the causation of disease through the interactions of

Environment - all that which is external to the individual human host

Host - a person that affords subsistence or lodgment to an infectious agent or has intrinsic factors favorable for developing a chronic disease

Agent - refers to extrinsic factors whose presence or relative absence is essential for the occurance of the disease

long latency period

long interval between initial exposure to a disease cause and the appearance of a disease

low incidence/prevalence

infrequent occurrence of certain diseases that are caused by environmental factors

Paracelsus

one of the founders of modern toxicology. concepts of dose response relationship and notions of chemicals having target organs. encouraged use of experimental animals

Mathieu Orfila

founder of toxicology. forensic toxicology

poison

any agent capable of producing a deleterious response (death of severe impairment of biological functioning) in a biologcal system

toxic agent

a material or factor that can be harmful to biological systems (radiation, spider venom)

toxicity

degree to which something is poisonous (theres high and low toxicity)

toxic substance

material that has toxic properties

toxicant

man made toxic substances or results from human activity

toxin

toxic substance that is made by living organisms

exposure asssessment

examines the evidence that associates exposure to the toxicity of an agent

hazard

inherent capability of an agent or situation to have an adverse effect

dose

amount of a substance administered at one time

dose response curve

describes the effect of exposure to a chemical upon an organism. response quantitavely shifts as overall exposure to the substance increases. curve generally has S shape

threshold

lowest dose at which a particulat response may occur

population dose response

Lethal dose 50 LD50 is the dosage causing death in 50% of exposed animals. application of LD50 is to compare the toxicity of chemicals

dose-response relationships

correlative relationship between the characteristics of exposure to a chemical and the spectrum of effects caused by the chemical. used to establish association between a toxin and effects, minimum dosage needed, and accumulation of harmful effects

acute toxicity

when symptoms of poisoning occur immediately after exposure

sub chronic toxicity

repeated expoures for several weeks or months

chronic toxicity

exposures over long period of time to non lethal dose causing cumulative damage to specific organ

additive

when the combination of two chemicals generates an effect that is equal to their individual effects added together

synergism

when combined effect of several exposures is greater than the sum of individual effects

potentiation

when a chemical that isnt toxic causes another chemical to become more toxic

coalitive interaction

when several agents (compounds) that have no known toxic effects interact to produce a toxic effect

antagonism

when two substances administered together interfere with each others actions or one interferes with the other

exposure assessment

examines the evidence that associates exposure to the toxicity of an agent. 4 step process

environmental policy

a statement by an organization of its intentions & principles in relation to its overall environmental performance. provides a framework for action and for settling of environmental objectives and targets

policy analysis

facilitates social assessment of risk and damage by clarifying the cost of reducing environmental harm in terms of foregone economic returns

risk assessment

the process for determining health risks associated with environmental and other hazards

risk management

involves the adoption of steps to eliminate identified risk or lower is to acceptable level

environmental impact

any environmental change resulting from performing public policy mandates

environmental impact assessment eia

a process that reviews the potential impact of anthropogenic activities with respect to positive or negative environmental consequences for humans, species of animals and plants

health impact assessment hia

a method for describing and estimating the effects that a proposed project or policy may have on the health of a population