A Life Course Approach to the Study of Ageing Flashcards
What are the 2 key current population trends?
Fertility rates - decreased in 1960s then plateaued
Life expectancy - increasing
What are the defining characteristics of population ageing?
Increased absolute number of old people
Increased proportion of old people in population - age structure change
Define epidemiology
Study of distribution and determinants of health-related states/events
What is life-course epidemiology?
Long-term effects of whole-life physical/social hazard exposures
How can an early-life exposure affect late life disease development?
Indirectly - via chains of pathways
What is the foetal origins of adult disease hypothesis and how did it originate?
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
Name 3 life course studies
National Survey of Health and Development
Hertfordshire Cohort Study
Caerphilly Study
What is the Hertfordshire Cohort study?
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
What is the Caerphilly study?
Started measuring in mid-adulthood
Relied on recall of earlier life exposures - to link to later life diseases
What is the National Survey of Health and Development?
Studies effect of lifetime exposures
On pregnancy/birth, childhood development, education, adult health and function
What is Kuh et al.’s definition of healthy ageing?
Survival to old age
Delayed chronic disease onset
Optimal functioning for max. life of time
Which lifetime influences were found to increase adult premature mortality in the NSHD?
Lower childhood and adult socioeconomic position
Lower childhood cognitive ability
Over/underweight in childhood and adulthood
Adult severe psychiatric disorder
What is the practical aim of life-course epidemiology?
Identify at-risk individuals early
Identify targets and timings for interventions to prevent disease - enable optimal functioning for max. length of time
What are the benefits of studying function?
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
What is the hypothetical model of function over the life-course?
Increase in early life
Plateau in early-mid adulthood
Decline in later life
Which features of the hypothetical model of function over the life-course can vary between individuals to give different trajectories?
Rate of development
Level of peak
Timing of decline onset
Rate of decline
Which features of the hypothetical model of function over the life-course are early life exposures more likely to affect?
Rate of development
Level of peak
Which features of the hypothetical model of function over the life-course are adult life exposures more likely to affect?
Decline
Why are there no datasets with repeat measures of function in the same people across their life-course?
Earlier medical technology restricted ease of measurements
What are the 2 types of data used to measure function across the life-course?
Cross-sectional - covering wide age range
Combining data from different cohorts - with overlapping age groups
What are the limitations of measuring function over the life-course?
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
Does grip strength follow the hypothetical model of function?
Yes
Does blood pressure follow the hypothetical model of function?
No
How does mean systolic blood pressure change across the life-course in the general population?
Starts to increase in mid-life
How does mean systolic blood pressure change across the life-course in Whitehall civil servants and what does this suggest?
Steady across mid-life
Starts to increase in late-life
Mean population trajectory may be unhealthy
Define physical capability
Capacity to perform physical tasks of daily living
What are the ways of assessing physical capability?
Early assessments
Performance-based assessments
What are early assessments of physical capability?
Self-reports of functional limitations and abilities
What are the limitations of early assessments of physical capability?
Validity and reproducibility - does not consider cognitive inabilities that may affect functional performance
How to measure change over time
Which clinical tests are used to performance-based assessments of physical capability?
Walking speed
Chair rise
Standing balance
Grip strength
Which aspects of healthy ageing are measures of physical capability linked to?
Increased survival rates
Delayed disease/disability onset
Increased mental wellbeing
Which physical capability in younger populations is linked to mid-life mortality?
Adolescent muscle strength
Which factors across the lifetime are associated with physical capability?
Genes Growth and body size Lifestyle and socioeconomic circumstances Cognitive capability Chronic disease
How is prenatal growth linked to grip strength and what does this suggest?
Higher birthweight linked to increased grip strength, lean mass, muscle fibres
Foetal growth critical for muscle fibre development
How is childhood growth linked to chair rise performance and why?
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
How is childhood socioeconomic position linked to physical capability?
Lower childhood paternal socioeconomic class - poorer physical functions in later life
Regardless of later life environment
How is childhood cognition linked to balance?
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
How is a disadvantaged childhood linked to adult respiratory function trajectories?
More negative effect on lung function in smokers than non-smokers
Upbringing and adult smoking both affect trajectories
What is left ventricular mass index (LVMI) a predictor of?
Cardiovascular disease
Why might mid-life be a sensitive period for cardiovascular disease?
Faster increase in systolic blood pressure in midlife linked to increased LVMI in late-life
