A biosocial approach to healthy ageing: The interplay between social isolation and inflammation
Lead Research Organisation:
University College London
Department Name: Epidemiology and Public Health
Abstract
Social isolation of older adults is associated with mortality and a range of health problems - an issue of particular saliency given the COVID-19 pandemic and associated lockdown. One possible mechanism implicated in the process of social isolation getting "under the skin" and affecting health is chronic inflammation, a widespread phenomenon in older people that is a known risk factor for a wide range of health conditions.
This PhD project will use data from the English Longitudinal Study of Ageing to explore the associations between social isolation and healthy ageing outcomes, and whether inflammation is a possible mediator of this relationship. The project started with the operationalisation of a measure of healthy ageing based upon the intrinsic capacity construct outlined by the World Health Organisation, for which no standard measure currently exists. Intrinsic capacity refers to an individual's capacity in 5 domains of function (cognition, locomotion, sensory, vitality, psychological) and, together with an individual's environment, determines functional ability in older age. The association between social isolation and intrinsic capacity will be explored in cross-sectional and longitudinal analyses, before testing the possible mediation effect of inflammation.
This PhD project will use data from the English Longitudinal Study of Ageing to explore the associations between social isolation and healthy ageing outcomes, and whether inflammation is a possible mediator of this relationship. The project started with the operationalisation of a measure of healthy ageing based upon the intrinsic capacity construct outlined by the World Health Organisation, for which no standard measure currently exists. Intrinsic capacity refers to an individual's capacity in 5 domains of function (cognition, locomotion, sensory, vitality, psychological) and, together with an individual's environment, determines functional ability in older age. The association between social isolation and intrinsic capacity will be explored in cross-sectional and longitudinal analyses, before testing the possible mediation effect of inflammation.
Organisations
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| ES/P000347/1 | 01/10/2017 | 30/09/2024 | |||
| 2083028 | Studentship | ES/P000347/1 | 01/10/2018 | 30/09/2022 | Charlotte Campbell |
| Description | Background: An individual's social relationships are consistently shown to be associated with many aspects of health, especially in the context of healthy ageing. Social isolation of older adults is associated with mortality and a range of mental and physical health problems. One possible mechanism implicated in the process of social isolation affecting health is chronic inflammation, a widespread phenomenon in older people that is a known risk factor for a wide range of health conditions. Methods: Data from the English Longitudinal Study of Ageing (ELSA) was used to explore the associations between social isolation and intrinsic capacity, and whether inflammation was a mediator of this relationship. First, a measure of healthy ageing was operationalised based upon the intrinsic capacity (IC), which refers to capacity in 5 domains of function: cognition, locomotion, sensory, vitality, and psychological. Item response theory was used to generate an IC score in three waves of ELSA spanning 8 years. Latent growth curve models tested the association between social isolation and intrinsic capacity before cross-lagged panel models were used to test the possible mediation effect of inflammation, both using full information maximum likelihood to handle missing data. Results: The novel IC score was associated with key sociodemographic and health-related covariates and predicted subsequent difficulties with ADLs and IADLs, hospital admission and mortality. Lower social isolation was associated with higher baseline levels of IC but a steeper decline in IC over time. Inflammation was not found to mediate the association between social isolation and IC, but a bidirectional relationship between inflammation and IC was uncovered. Conclusions: Inflammation is not likely a key mechanism for social isolation to affect healthy ageing. Policy to reduce social isolation may not slow declines in health but could give older adults a better "starting point" and, therefore, more time in better health. |
| Exploitation Route | The thesis demonstrates how a new model of healthy ageing, intrinsic capacity, can be operationalised in longitudinal population surveys and how the validity of such models can be assessed, which has a clear impact on future research intending to measure intrinsic capacity. The results show that social isolation has a harmful effect on the capacity of older adults in England but that being more socially isolated does not speed up the decline of capacity with increasing age. This is a novel result in the academic literature and could be helpful to inform interventions attempting to prolong the healthy life expectancy of the population. The final analysis in this thesis shows that raised inflammation is probably not the mechanism through which social isolation damages health but highlights the importance of inflammation to the healthy ageing of older adults. This has implications for the academic understanding of social-biological pathways in health, as well as for policies that aim to promote healthy ageing in a population. |
| Sectors | Communities and Social Services/Policy,Healthcare |
| Description | Participation in the 3 Minute Thesis competition 2021 |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Other audiences |
| Results and Impact | Charlotte entered in the Institute of Epidemiology and Health Care 3 Minute Thesis competition and placed third. The 3 minute presentation outlined her PhD project in an accessible way for non-academic audiences. |
| Year(s) Of Engagement Activity | 2021 |
| Description | Poster at the Society for Longitudinal and Lifecourse Studies 10th Anniversary week 2020 |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Other audiences |
| Results and Impact | Charlotte presented a poster at the SLLS 10th Anniversary event in 2020. The poster was titled "The Operationalisation of a Multi-Dimensional Measure of Healthy Ageing in Observational Studies of Ageing" and was presented online alongside a recorded presentation. The poster won the 2020 Best Poster Award. |
| Year(s) Of Engagement Activity | 2020 |
| Description | Poster at the online Society for Social Medicine and Population Health conference 2021 |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Other audiences |
| Results and Impact | Charlotte presented an online poster at the SSM Annual Scientific Meeting in 2021. The poster was titled "The association between social isolation and a novel measure of intrinsic capacity in the English Longitudinal Study of Ageing (ELSA)" |
| Year(s) Of Engagement Activity | 2021 |
| Description | Presentation at the Society for Longitudinal and Lifecourse Studies conference 2022 |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Other audiences |
| Results and Impact | Charlotte Campbell completed a presentation at the SLLS 2022 conference "Growing Up and Growing Older Across Societies: Harnessing the Power of Comparative Research". The talk was part of the session on Ageing and was titled "Predicting functional ability, hospital admissions, and mortality using a novel measure of intrinsic capacity in the English Longitudinal Study of Ageing". |
| Year(s) Of Engagement Activity | 2022 |
| URL | https://www.slls.org.uk/events/slls-2022-annual-international-conference |
| Description | Presentation at the Society for Social Medicine and Population Health conference 2022 |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Other audiences |
| Results and Impact | Charlotte Campbell completed a presentation at the SSM Annual Scientific Meeting 2022 at the University of Exeter. The talk was part of the session on Ageing and was titled "Predicting functional ability, hospital admissions, and mortality using a novel measure of intrinsic capacity in the English Longitudinal Study of Ageing". |
| Year(s) Of Engagement Activity | 2022 |
| Description | Presentation for the International Centre for Lifecourse Studies in March 2021 |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Other audiences |
| Results and Impact | Charlotte presented her PhD project to the ICLS in March 2021. The talk was titled "A biosocial approach to healthy ageing: The interplay between social isolation and inflammation". The presentation sparked discussion about the PhD project as well as biosocial research. |
| Year(s) Of Engagement Activity | 2021 |