Theme 2 key areas

Question 1

Define epidemiology

Answer 1

Epidemiology is the study of determinants of disease across populations, and of ways to reduce the impact of these diseases on the health of the community.

Based on the idea that disease is not random and has causal and preventative factors that can be investigated in systematic ways.

Question 2

Define outbreak

Answer 2

The occurrence of disease cases in excess of normal expectancy.

Question 3

Define endemic

Answer 3

When an infection exists within a geographic population perpetually.

Question 4

Define pandemic

Answer 4

A global endemic.

Question 5

Describe epidemiological functions and their role in public health

Answer 5

Functions:
> Studying the determinants of disease
> Finding ways to reduce the impact of diseases on the health of the community
> Investigation of the causal and preventative factors of disease

Role in public health:
Public health draws on epidemiology - a scientific resource - to help guide clinical medicine and help to understand human biology.
Epidemiology contributes to the rationale for many public health policies and services and is an important tool for evaluation of effectiveness.

Question 6

Understand the epidemiological triad of disease

Answer 6

The epidemiological triad is a model of health and consists of 3 key causal factors for disease:

1. Agent - this could be physical (eg. radiation), chemical (eg. gasses), nutrient (eg. from your diet), psychological (eg. stress) or biological (eg. bacteria, viruses and insects).
2. Environment - this could be biological (eg. animals and plants), physical (eg. geology, weather, climate and water quality) or social (eg. culture, education, politics and social economic status).
3. Host - these are the individual factors that can predetermine your susceptibility to disease (eg. immunity, inherent resistance, age, gender, ethnicity, lifestyle, exercise, nutrition and health knowledge).

Question 7

Describe the levels of prevention

Answer 7

There are 3 key levels of prevention:

1. Primary prevention - aims to avoid the development of a disease and remove risk factors (eg. Vaccination programs).
2. Secondary prevention - aims for early detection and treatment to prevent the progression of an already present disease (eg. screening programs).
3. tertiary prevention - aims to reduce the complications of an already established disease (eg. rehabilitation programs).

Question 8

Where might you find accurate epidemiological data?

Answer 8

Australian Institute of Health and Welfare

Department of Health

WHO

Australian Bureau of Statistics

Question 9

What is a descriptive study?

Answer 9

Explores: who, what, when, where (ie. person, place and time). These studies just describe what is happening.
ie. who has the disease? what is the disease? when/is the disease common or rare? where does the condition arise?

the typical study design is that of an observational community health survey.

Question 10

What is an analytical study?

Answer 10

An analytical study explores: why and how. These studies examine associations and test hypothesis.
ie. how did the individual get the disease? and why did they get it?

The typical study design could be a cohort study or a case control study.

Question 11

What is the difference in global and national life expectancies?

Answer 11

In Australia, a male’s life expectancy is currently 80 whilst a female’s is 84. In Australia, women have a life expectancy around 4 years longer than men whilst Indigenous people have life expectancies 5-10 years lower.

At a global level, there are some underdeveloped nations who have life expectancies 10 years less than their developed counterparts.

Question 12

Why do we measure health status?

Answer 12

Measuring health status allows us to:
Identify health issues
Monitor progress
Evaluate health promotion strategies

Question 13

What is a DALY?

Answer 13

A DALY is a disability adjusted life year. It takes in the years of life lost and the years of life with disability. They allow us to have some way of measuring health that is not just death.

Question 14

What is a YLL?

Answer 14

A YLL is a year of life lost.

Question 15

What is a YPLL?

Answer 15

A YPLL is a year of productive life lost.

Question 16

What is a YLD?

Answer 16

A YLD is a year lived with disability.

Question 17

What is a QALY?

Answer 17

A QALY is a quality adjusted life year. We use this to determine the quality of life specifically when evaluating the effectiveness of medical intervention.

Question 18

What is the social demographic index?

Answer 18

A summary measure of a geography’s socio-demographic development. It is based on average income per person, educational attainment, and total fertility rate (TFR).

Question 19

Define mortality

Answer 19

Being dead

Question 20

Define morbidity

Answer 20

Being diseased

Question 21

What is a dichotomous outcome?

Answer 21

When you get 1 of only 2 possible outcomes.

Question 22

What is a predictor variable?

Answer 22

Something that is going to influence the outcome.

Question 23

What is a rates ratio?

Answer 23

An odds ratio is a measure of association between an exposure and an outcome.

Question 24

What is an alpha level?

Answer 24

An alpha level is chosen by the researcher before any statistical testing is done. It is a statement about the level of risk that the researcher is prepared to accept that their results may bean error.

Question 25

What is a confidence interval?

Answer 25

A confidence interval is the possible range around the estimate. ie. how stable the estimate would be if you repeated the same experiment.

Question 26

What is an alpha level?

Answer 26

An alpha level is chosen by the researcher before any statistical testing is done. It is a statement about the level of risk that the researcher is prepared to accept that their results may bean error.

eg. If a researcher sets their alpha level at 5, they are prepared to accept the risk that 5% of their results are due to chance and 95% are not due to chance.

Question 27

What is the relationship between alpha levels, levels of confidence, odds ratios and confidence intervals?

Answer 27

The lower the alpha level, the higher the level of confidence and the narrower the confidence interval.

The higher the alpha level, the lower the level of confidence and the wider the confidence interval.

The odds ratio is a statistic so it doesn’t change.

Question 28

Understand the different types of studies

Answer 28

Case report:
A descriptive study where in which you report that someone has something.
ie. You provide a detailed description of an individual patient and possibly details of the suspected exposure.

Case series:
A descriptive study. A collection of similar case reports. this method is often used to identify an outbreak.

Cohort study:
An analytical study where in which you examine a cohort who starts the study disease free and follow up to see if they have been exposed to a risk factor and if if resulted in the development of a disease.

Case control:
An analytical study where in which you examine a group of people who have the outcome and a group who don’t and gather information on whether they were exposed to a risk factor or not. In this study, the sick people are the case control.

Question 29

Understand the difference between observational and interventional studies

Answer 29

During observational studies, there is no intervention from the research and the world continues on as normal.

During interventional studies, there is intervention from the researcher.

Question 30

What is confounding and how is it controlled?

Answer 30

Confounding is an issue we see in observational studies where in which elements can influence the results of a study. making it difficult to determine whether the exposure actually caused the outcome. This is why we just determine association.

We need to statistically adjust for confounding by adjusting the odds ratio. We cannot however, adjust for unmeasured confounders.

Question 31

What is selection bias?

Answer 31

Bias that occurs through the selection of individuals which results in randomisation not being achieved.

Question 32

What is recall bias?

Answer 32

A systematic error caused by differences in the accuracy or completeness of the recollections retrieved by study participants regarding events or experiences from the past.

ie. Some participants recall more vividly whilst others do not.