Introduction to Epidemiology & Public Health

Question 1

What is epidemiology?

Answer 1

Study of the distribution and determinants of diseases in human populations

Question 2

What is public health?

Answer 2

The science and art of prolonging life, preventing disease and promoting health by the organised efforts of society.

Question 3

What is the difference between epidemiology and clinical medicine?

Answer 3

Clinical medicine is concerned with people who already have the disease and the study of the prognosis and how it can be treated.

Epidemiology seeks to understand the antecedents of disease and identify its causes, so making possible its prevention.

Question 4

What is an epidemiological ‘rate’ in the most general sense?

Answer 4

The ratio of number of cases of disease to the size of the catchment population

Question 5

What is the difference between incidence and prevalence rates?

Answer 5

Incidence rates measure the occurence of new cases of disease, whereas prevalence rates relate to existing cases of disease.

Question 6

Which one of the following is a true rate, prevelance or incidence?

Answer 6

Incidence, as it specified a period of time over which the new cases of disease occur. In contrast, prevalence is not a true ‘rate’ as it does not.

Question 7

What are the 5 stages of clinical medicine?

Answer 7

1. Presentation
2. Investigation
3. Diagnosis
4. Treatment
5. Review

Question 8

What are the public health equivalents of the 5 stages of clinical medicine?

Answer 8

1. Presentation - measuring burden of disease
2. Investigation - comparing rates of disease between population
3. Diagnosis - drawing conclusions about causes of disease
4. Treatment - implementing policies for prevention/treatment
5. Review - evaluation of preventive and therapeutic health services

Question 9

What is another term for ‘population at risk’?

Answer 9

The catchment population

Question 10

What are mortality rates?

Answer 10

Fatal cases (death) per 1000

Question 11

What is the difference between morbidity and mortality?

Answer 11

Morbidity is a measure of sickness or disease within a geographic area while Mortality is a measure of deaths within a population or geographic area.

Question 12

What is the “iceberg of disease” analogy?

Answer 12

That only a portion of those with a condition are known to clinical services, the majority remainder lying ‘below the surface’ aren’t.

Question 13

What types of diseases does the “iceberg of disease” refer to?

Answer 13

Diabetes, hypertension, CHD

Question 14

What are the two important public health implications from the disease iceberg?

Answer 14

1. Infectious disease - communicable diseases maybe susceptible to minorities in a population eg. rubella in pregnancy
2. Any disease - small risk distributed through a wide population, small elevations of risk factors may be associated with only a small risk of complications but much more common so contribue to morbidity

Question 15

Communicable diseases can be commonly categorised as endemic and epidemic, what do these both mean?

Answer 15

• Endemic - when they persist for long periods within a community
• Epidemic - when the occurrence of disease episodes increases substantially for a limited period of time

Question 16

What examples of epidemiological methods can be used to compare disease rates?

Answer 16

• Correlations across time and place
• Cross-sectional studies
• Cohort studies
• Case-control studies
• Intervention studies
• Collations

Question 17

If the true finding is that the exposure has caused the disease, what alternative explanations are there for these findings?

Answer 17

Could be due to:

• Chance
• Confounding
• Bias

Question 18

If one observes no difference in disease rates between two differently exposed groups, then what are the alternative explanations?

Answer 18

• Insuffiecient power
• Negative confounding
• Imprecise measurement

Question 19

What is a risk factor?

Answer 19

A characteristic that identifies a group at increased or reduced risk of disease.

Can be correlational or predictors, a risk factor is statistically associated with disease.

Question 20

Risk factors may or may not be modifiable, what does this mean?

Answer 20

By modifiable it means whether or not they can be changed, so modifiable risk factors include smoking, high BP, physical activity

Whereas non-modifiable risk factors are age, gender, background etc.

Question 21

What is meant by ‘cause’ of a disease?

Answer 21

Something that increases the risk of disease. Causal factors may or may not be modifiable.

Question 22

What does prevention of disease depend upon?

Answer 22

Identifying modifiable risk factors which are causally related to the disease and whose effects are reversible.

Also depends upon required intervention achieving adequate coverage of the groups at risk.

Question 23

What is primary prevention and what are some examples?

Answer 23

Reduction of incidence of disease among healthy individuals.

• removing primary agent (lead in paint)
• interrupting transmission of an infective agent (safe sex)
• protecting individual from env hazards (hard hats on building sites)
• improving host resistance (vaccination)

Question 24

What is secondary prevention?

Answer 24

Early diagnosis/detection of preclinical disease + screening, (eg. cervical cytology) and treatment to prevent progression or recurrence

Question 25

What is tertiary prevention?

Answer 25

Treatment of established disease to prevent complications or relieve distress. Synonymous with good clinical care.