Y2 Session 1 - Introduction to Epidemiology and the Burden of Disease

Question 1

What is epidemiology?

Answer 1

How often diseases occur in different groups of people and why, using this knowledge to control health problems.

Question 2

What is an endemic and an epidemic?

Answer 2

Endemic - diseases that reside within a population

Epidemic - diseases that visit a population

Question 3

What are the three types of prevention

Answer 3

1. Primary - the prevention of disease by controlling exposure to risk factors e.g. not smoking
2. Secondary - applying measures in early illness for appropriate treatment e.g. controlling hypertension with hypertensive drugs to prevent progression.
3. Tertiary - applying measures to reduce or eliminate long-term impairments to minimise suffering from existing or past health conditions e.g. physio for a patient who has had a stroke to get as close to normal activities

Question 4

What 5 questions should we be thinking of when statistics don’t look as we expected them to?

Answer 4

1. How could we explain this result?
2. What do I need to measure to figure this out?
3. What might I be getting wrong?
4. How do I explain this to people who aren’t epidemiologists?
5. On the basis of what I think is going on, what should we do next?

Question 5

What is an exposure in epidemiology?

Answer 5

What we’re testing the outcome of e.g. the effect of antihypertensives are to reduce blood pressure so the outcome would be blood pressure and the exposure would be antihypertensives.
Whilst this example is a drug, this can also be a behaviour or a demographic however.

Question 6

What is the demographic transition model?

Answer 6

It is a graph measure the birth rate, death rate and total population. It has 5 stages to it.

Question 7

What occurs in stage 1 of the demographic transition model?

Answer 7

The birth rate and death rate are high and stable, leaving the total population at a stable level or slow increase.

Question 8

What occurs in stage 2 of the demographic transition model?

Answer 8

The birth rate remains high but the death rate begins fall rapidly, so the total population rapidly increases.

Question 9

What occurs in stage 3 of the demographic transition model?

Answer 9

Birth rate begins to fall as death rate begins to fall more slowly. Therefore, total population maintains its increase but the increase is slower now.

Question 10

What occurs in stage 4 of the demographic transition model?

Answer 10

The birth and death rate are low and the total population starts to stabilise.

Question 11

What occurs in stage 5 of the demographic transition model?

Answer 11

The birth rate slowly begins to rise, the death rate remains low and the population is stable and begins to slowly increase.

Question 12

What is the epidemiologic transition model?

Answer 12

A model based of the demographic transition model, broken down into 4 stages with explanations of why the population number shifts.

Question 13

What is the pestilence and famine (pre) stage of the epidemiologic transition?

Answer 13

The first phase. In the UK up to the 1800s.
It begins with urbanisation and constraints on food supply. Therefore, birth rates are high but so are mortality rates. With a low life expectancy at birth.

Question 14

What is life expectancy?

Answer 14

Average life-span throughout a population, whilst life expectancy might be 34 in some areas, it might be because death in childbirth is high and very common but life span for many individuals might be 70+

Question 15

What is the receding pandemics (early) stage of the epidemiologic transition?

Answer 15

The second stage, around 1800s-1950 in the UK.
Agriculture develops, improving nutritions. Water, sanitation and hydration also improves, along with vaccines to increase life expectancy. This reduces mortality and the birth rate remains high.

Question 16

What is the degenerative and man-made disease (late) stage of the epidemiologic transition?

Answer 16

The third stage, from the 1950-2010s in the UK.
Lifestyle factors and NCDs (non-communicable diseases, these are not spread from person to person and are chronic conditions of an individual) predominate like cancer and CVD.
Environmental and global determinants drive obesity and other risk factors for NCDs.
Technology reduces need for physical labour.
Addiction, violence and other issues emerge.

Question 17

What is the delayed degenerative diseases and emerging infections (post) stage of the epidemiologic transition?

Answer 17

The final phase, circa 2010 onwards in the UK.
Health technology can delay morbidity at a high financial cost.
Emerging zoonotic disease becomes a threat.
Inequalities within and between countries come to light.

Question 18

What is a population pyramid?

Answer 18

A pyramidal diagram that has the percentage of population on the bottom axis and age increasing up the y-axis. The graph is divided in half to show female and male distributions, to make a pyramid shape. This graph is of western Africa.

Question 19

What shape would a rapidly growing population appear like?

Answer 19

An almost perfect triangle, as the infant mortality rate has lowered.