Population Health

Question 1

Why do we study epidemiology?

Answer 1

To understand the burden and the causes of the disease

Question 2

What is the role of epidemiology

Answer 2

Measurement of amount and and distribution of disease, and natural history of disease

Question 3

What is prevalence and how do we measure it?

Answer 3

Prevalence is the number of disease cases in a population at a given time.

Measured via Number of affected individuals
Total number of persons in population

Question 4

What is incidence and how can we measure it

Answer 4

Incidence is the number of new disease cases developing over a specific period of time in a defined population

Rate = no of new cases of a disease in a period
No of indictable in the population at risk

Question 5

What kind of studies are prevalence estimates obtained from?

Answer 5

Cross -sectional studies or derived from registers

Question 6

What kind of studies are incidence estimates obtained from

Answer 6

Longitudinal studies or derived from registers

Question 7

What is the index used for the measurement of dental caries in permanent teeth?

Answer 7

DMF ( permanent teeth)
DMFT - decayed missing and filled teeth
DMFS - decayed missing and filled surfaces

Question 8

What is the index used for the measurement of dental caries in the deciduous teeth?

Answer 8

• dmft = decayed , missing filled teeth
• e =indicated for extraction/exfoliated

Question 9

What does D3MFT or d3mft mean?

Answer 9

Decay into the dentine

Question 10

What does D1MFT or d1mft mean?

Answer 10

Decay into the enamel

Question 11

What are the limitations to the DMF/dmf index

Answer 11

• Teeth are extracted for reasons other then caries
• Influenced by access e.g interproximal surface
• Difficulty in differentiating fissure-sealant from restorations - underestimate caries
• influenced by past disease activity
• cannot be used for rot caries

Question 12

What is the average dmft

Answer 12

2

Question 13

What is the definition of a risk factor

Answer 13

A environmental, behavioural or biological factor confirmed by a temporal. Sequence, usually increasing the probability of a disease occurring, and, if absent or removed, reduces the probability.

Question 14

Define a cause

Answer 14

External agent which results in disease in susceptible individuals

Question 15

What is a confounding variable

Answer 15

Particular type of extraneous variable which for some reason has been left uncontrolled. The result is that on looking at the findings of an experimental study, rather than only one possible variable exerting influence on an outcome, there are found to be others, which are said to be confounding the results

Question 16

What are the three common indices of risk

Answer 16

Absolute
Relative
Attributable

Question 17

What is absolute risk

Answer 17

It is the most basic measure
Incidence rate of disease amongst people exposed to the agent

Question 18

Why is absolute risk not very useful

Answer 18

As it assumes no risk incurred by people not exposed to agent

Question 19

What is attributable risk

Answer 19

Difference between incidence rates in exposed and non exposed groups

Question 20

What is relative risk

Answer 20

Ratio of incidence rate in exposed group to incidence rate in non exposed group

Question 21

What is a cohort study

Answer 21

Individuals observed over a period of time to measure frequency of occurrence of disease among
- People exposed to risk factor
- people not exposed to risk factor

Question 22

What is a case control study

Answer 22

Compare individuals with disease ( cases) to those without disease ( control) and trace back to asses risk factors