-What is Hepatitis A caused by?

-Symptoms?

-Transmission?

-HOW DO YOU THINK AUTHORITIES HAVE LINKED THESE BERRIES TO HEPATITIS A?

Identify and describe the main features of

epidemiology using lung cancer as an example.

9.4.6.2.1

Epidemiology

Derived from the word epidemic.

-’ology’ means ‘the study of’.

Basically, it is the study of epidemics (includes infectious and non-infectious disease though).

More specifically, it is the study of the relationship between incidence and risk factors for diseases in populations.

All about ‘cause and effect’

The data can be used to minimise the causes and improve health of a population.

“Medical detectives”

Lung cancer and smoking: the history

Tabacco smoke contains carcinogens.

An uncontrolled growth of tumours in the lungs.

Growing tumours destroys lung tissue and breathing becomes more difficult.

Lung cancer was rare, until mass production of cigarettes started and the companies gave them away for free to soldiers.

Smoking related diseases kills 14 900

Australians

By 1970s lung cancer had gone from rare condition to number 1 cause of death!

Once the link between smoking and lung cancer became more obvious smoking rates decreased lung cancer cases decreased.

Epidemiology studies have been very

important in showing that smoking

increases the chance of getting lung cancer

Well, how did they do it then?

Further information

Types of epidemiology studies

Observational: outcomes of risk factors examined.

Descriptive Analytical

Experimental: you have control over risk factors.

Randomised Controlled Trial

Descriptive

Collection of data from those affected.

-inherent characteristics (e.g. sex, age)

-activities (e.g. occupation, drugs, alcohol, leisure)

-conditions (e.g. socioeconomic, location)

Analytical

Analyse data using a comparison group.

To determine risk factors and establish link between cause and effect.

-E.g. Nanna’s mixed berries?

smoking and lung cancer.

Observational epidemiology further subdivided into…

To establish cause and effect for smoking

1. High relative risk

The risk of death from lung cancer is 10 x that for a smoker than a non-smoker.

2. Consistency

Different researchers using different populations have come up with the same results.

3. A graded response to a graded dose

Death rate increased with the number of cigarettes smoked a day.

4. A time relationship

Smoking must precede lung cancer to be caused by it.

The rate of smoking has decreased and is reflected in a decrease in lung caner over time.

5. A possible mechanism

Chemicals in smoke which are known to be carcinogens- mechanism for mutations in DNA.

1. Large sample size

2. Control of variables (e.g. age, race, gender)

3. Data that is collected (e.g. lifestyle, environment, morbidity and mortality rate)

4. Data analysis (e.g. compare for common data with and without disease and in people with disease)

5. Long time period

6. Peer reviewed.

Some characteristics to identify cause

HSC BIOLOGY EXAM

Practise with some of these HSC questions.

2012. Short answer Q 26. 5 marks (hard)

2011. Short answer Q 27. 4 marks (ok)

2007. Short answer Q 25. 3 marks (ok)

2006. Short answer Q 27. 5 marks (hard)

From 2007 (ok)

Epidemiology studies indicate that there is a relationship between smoking and the incidence of lung cancer.

What information would have been gathered to establish this relationship? (3 marks)

Marking notes

In better responses candidates identified characteristics of a sound epidemiology study and linked this to the need to establish a relationship between smoking and lung cancer.