A Life Course Approach to the Study of Ageing

Question 1

What are the 2 key current population trends?

Answer 1

Fertility rates - decreased in 1960s then plateaued

Life expectancy - increasing

Question 2

What are the defining characteristics of population ageing?

Answer 2

Increased absolute number of old people

Increased proportion of old people in population - age structure change

Question 3

Define epidemiology

Answer 3

Study of distribution and determinants of health-related states/events

Question 4

What is life-course epidemiology?

Answer 4

Long-term effects of whole-life physical/social hazard exposures

Question 5

How can an early-life exposure affect late life disease development?

Answer 5

Indirectly - via chains of pathways

Question 6

What is the foetal origins of adult disease hypothesis and how did it originate?

Answer 6

Barker linked birthweight (marker of foetal growth) to various health outcomes
Undernutrition during critical developmental periods in utero has long-term effects on chronic disease risk - by affecting structure/function of organs, tissues, systems

Question 7

Name 3 life course studies

Answer 7

National Survey of Health and Development
Hertfordshire Cohort Study
Caerphilly Study

Question 8

What is the Hertfordshire Cohort study?

Answer 8

All births in county in 1930s
Traced individuals in later life
Linked old age health to birth measurements
Lacking mid-life data - may be unknown mid-like exposures affecting later disease risk

Question 9

What is the Caerphilly study?

Answer 9

Started measuring in mid-adulthood

Relied on recall of earlier life exposures - to link to later life diseases

Question 10

What is the National Survey of Health and Development?

Answer 10

Studies effect of lifetime exposures

On pregnancy/birth, childhood development, education, adult health and function

Question 11

What is Kuh et al.’s definition of healthy ageing?

Answer 11

Survival to old age
Delayed chronic disease onset
Optimal functioning for max. life of time

Question 12

Which lifetime influences were found to increase adult premature mortality in the NSHD?

Answer 12

Lower childhood and adult socioeconomic position
Lower childhood cognitive ability
Over/underweight in childhood and adulthood
Adult severe psychiatric disorder

Question 13

What is the practical aim of life-course epidemiology?

Answer 13

Identify at-risk individuals early

Identify targets and timings for interventions to prevent disease - enable optimal functioning for max. length of time

Question 14

What are the benefits of studying function?

Answer 14

More dynamic than disease/mortality endpoints
Can study variation in population
Can identify high-risk and low-risk subgroups
Can study processes from early life - before disease

Question 15

What is the hypothetical model of function over the life-course?

Answer 15

Increase in early life
Plateau in early-mid adulthood
Decline in later life

Question 16

Which features of the hypothetical model of function over the life-course can vary between individuals to give different trajectories?

Answer 16

Rate of development
Level of peak
Timing of decline onset
Rate of decline

Question 17

Which features of the hypothetical model of function over the life-course are early life exposures more likely to affect?

Answer 17

Rate of development

Level of peak

Question 18

Which features of the hypothetical model of function over the life-course are adult life exposures more likely to affect?

Answer 18

Decline

Question 19

Why are there no datasets with repeat measures of function in the same people across their life-course?

Answer 19

Earlier medical technology restricted ease of measurements

Question 20

What are the 2 types of data used to measure function across the life-course?

Answer 20

Cross-sectional - covering wide age range

Combining data from different cohorts - with overlapping age groups

Question 21

What are the limitations of measuring function over the life-course?

Answer 21

Cannot distinguish the effects of age from period and cohort effects - may distort age-related changes
Measurements may need to change to be age-specific - e.g. cognitive tests for children/adults
Equipment used to measure function changes due to improved medical technology - increased accuracy

Question 22

Does grip strength follow the hypothetical model of function?

Answer 22

Yes

Question 23

Does blood pressure follow the hypothetical model of function?

Answer 23

No

Question 24

How does mean systolic blood pressure change across the life-course in the general population?

Answer 24

Starts to increase in mid-life

Question 25

How does mean systolic blood pressure change across the life-course in Whitehall civil servants and what does this suggest?

Answer 25

Steady across mid-life Starts to increase in late-life Mean population trajectory may be unhealthy

Question 26

Define physical capability

Answer 26

Capacity to perform physical tasks of daily living

Question 27

What are the ways of assessing physical capability?

Answer 27

Early assessments | Performance-based assessments

Question 28

What are early assessments of physical capability?

Answer 28

Self-reports of functional limitations and abilities

Question 29

What are the limitations of early assessments of physical capability?

Answer 29

Validity and reproducibility - does not consider cognitive inabilities that may affect functional performance How to measure change over time

Question 30

Which clinical tests are used to performance-based assessments of physical capability?

Answer 30

Walking speed Chair rise Standing balance Grip strength

Question 31

Which aspects of healthy ageing are measures of physical capability linked to?

Answer 31

Increased survival rates Delayed disease/disability onset Increased mental wellbeing

Question 32

Which physical capability in younger populations is linked to mid-life mortality?

Answer 32

Adolescent muscle strength

Question 33

Which factors across the lifetime are associated with physical capability?

Answer 33

``` Genes Growth and body size Lifestyle and socioeconomic circumstances Cognitive capability Chronic disease ```

Question 34

How is prenatal growth linked to grip strength and what does this suggest?

Answer 34

Higher birthweight linked to increased grip strength, lean mass, muscle fibres Foetal growth critical for muscle fibre development

Question 35

How is childhood growth linked to chair rise performance and why?

Answer 35

Weight gain in childhood - better midlife chair rise performance Weight gain in adolescence - poorer midlife chair rise performance As gain lean mass in childhood - fat mass in adolescence

Question 36

How is childhood socioeconomic position linked to physical capability?

Answer 36

Lower childhood paternal socioeconomic class - poorer physical functions in later life Regardless of later life environment

Question 37

How is childhood cognition linked to balance?

Answer 37

Higher childhood cognition - increased balance in mid-life Effect weakens with age - cognition affects peak of balance - in decline early life factors have smaller impact - later life factors take over

Question 38

How is a disadvantaged childhood linked to adult respiratory function trajectories?

Answer 38

More negative effect on lung function in smokers than non-smokers Upbringing and adult smoking both affect trajectories

Question 39

What is left ventricular mass index (LVMI) a predictor of?

Answer 39

Cardiovascular disease

Question 40

Why might mid-life be a sensitive period for cardiovascular disease?

Answer 40

Faster increase in systolic blood pressure in midlife linked to increased LVMI in late-life