Lifetime Epidemiology

Question 1

Why do conventional adult lifestyle models of chronic disease not work?

Answer 1

Poor predictors of individual risk

Inability to fully explain observed geographical, temporal and social variations

Question 2

Why is it important to consider as early as pregnancy in chronic disease?

Answer 2

Undernutrition during pregnancy has long-term effects on chronic disease risk by programming the structure or function of body systems.

Question 3

What is life course epidemiology?

Answer 3

The study of the ‘biological, behavioural, and psychosocial pathways that link physical and social exposures during gestation, childhood, adolescence and adult life, and across generations, to adult health, function and disease risk

Question 4

What were the 3 main theories of disease aetiology?

Answer 4

1. fetal/developmental origins of adult disease
2. adult lifestyle
3. social causation theories

Question 5

How does the life course approach incorporate the importance of time?

Answer 5

• timing, duration and temporal ordering of different exposures
• characteristics of any one specific exposure/phenotype over time

Question 6

What is the aim of considering time in the life course approach?

Answer 6

1) Providing aetiological insights into lifelong processes that influence ageing and health

2) Generating evidence on the type, timing and targeting of most effective interventions across life to promote health and wellbeing

Question 7

What are the 4 needs to building a theoretical life course framework?

Answer 7

1. Use of visual box diagrams to illustrate pathways.
2. More than just the collection of exposure
3. Arranging variables in a diagram to show how they relate to each other over time, especially highlighting connections
4. Hypothesis generating and testing

Question 8

How to get from a theoretical life-course framework to a testable hypothesis?

Answer 8

1. Identify the key factors of the life course framework
2. Identify specific variables
3. Define hypothesis
4. Consider the variable over time

Question 9

What were life course models originally used for?

Answer 9

Used to test the influence of timing and duration of exposure across life on later disease risk

Question 10

What kinds of models can be used to show the effect of timing and duration of exposure across life?

Answer 10

Critical and sensitive period models

Accumulation of risk models

Question 11

What types of accumulation of risk models are there?

Answer 11

Independent and uncorrelated insults

Correlated insults

Question 12

What kinds of correlated insults are there?

Answer 12

Risk clustering

Chains of risk

Question 13

Are life course models mutually exclusive?

Answer 13

No, they can operate simultaneously

Question 14

What are critical and sensitive period models?

Answer 14

An exposure in earlier life has lifelong effects on structure or function (which may or may not be modified by later experience)

Question 15

What is a critical period?

Answer 15

The only time period during which an exposure (A) has an effect

Question 16

What is a sensitive period?

Answer 16

A time period during which an exposure (B) has a greater effect than outside this period

Question 17

What are accumulation of risk models?

Answer 17

Exposures or insults gradually accumulate across life through episodes of illness and injury, adverse environmental conditions and health damaging behaviour

Question 18

What is an accumulation of independent risks?

Answer 18

The accumulation of exposure to different, uncorrelated risk factors (A, B and C) causes long term damage and increases disease risk

Question 19

What is the accumulation of clustered risk?

Answer 19

The accumulation of exposure to different risk factors (A, B and C) which are clustered (because they are each associated with another risk factor (D)) causes long term damage and increases disease risk

Question 20

What are the chains of risk?

Answer 20

Childhood factors can set off a chain reaction, leading to a sequence of either negative or positive events.

Question 21

What is the chains of risk additive effect model?

Answer 21

Each exposure (A, B) not only increases the risk of subsequent exposure (B, C, respectively) but also has an independent effect on disease risk (irrespective of later exposure)

Question 22

What is the chains of risk trigger effect model?

Answer 22

Earlier exposures (A and B) influence risk of subsequent exposures BUT have no effect on disease risk without the final link in the chain (C)