26 research outputs found
Exploring frailty and cognitive functioning trajectories in later life
Understanding the ageing process in later life is a crucial step in identifying
those at highest risk of health decline, and in implementing effective
prevention and treatment strategies. However, measuring the ageing process
is a complex and divisive issue. As chronological age does not necessarily
capture the vast heterogeneity of older age, we require the development of
quantifiable health states. This thesis explored two of these states: Frailty
and mild cognitive impairment. A consensus on the concept of frailty and
how it should be measured remains elusive; however, it is generally
understood to describe a state of higher vulnerability to adverse events such
as disease, disability, dementia, and death. Mild cognitive impairment (MCI)
is a health state that describes a borderland between normal cognitive
functioning and dementia, exhibited by mild subjective and objective
cognitive impairments but a retained independency and ability to undertake
activities of daily living. This thesis explored later life ageing trajectories using
these health states and ultimately sought to provide a foundation for further
research and clinical care to build upon.
The first study acts as an introduction to the concept of frailty by conducting a
systematic review of publications that explore frailty trajectories. After
screening 8,318 publications, 25 met the eligibility criteria. Findings showed
that the field has a considerable degree of heterogeneity in how studies
measure frailty, the statistics they use to interpret their results, and the types
of populations they sample. Despite this, some valuable conclusions can be
made: as expected, frailty increases with age, and these increases are
consistently associated with certain factors such as socioeconomic factors,
social support, physical activity, and brain pathologies. I conclude that more
longitudinal research is required in the field, specifically research that
compares and contrasts the ways in which frailty is quantified.
The second study investigated the association between chronic inflammation
and frailty trajectories in the Lothian Birth Cohort 1936. Using two common
measures (Frailty index and Fried phenotype) and two blood-based
inflammatory biomarkers (Fibrinogen and C-reactive protein), frailty is tracked
over approximately 12 years. Findings showed that Fibrinogen was
significantly associated with higher baseline Frailty index score (β = 0.011,
95% CI [0.002, 0.020], p < .05). Additionally, over the 12-year follow-up,
higher baseline C-reactive protein (β = 0.001, 95% CI [0.000, 0.002], p < .05)
and Fibrinogen (β = 0.004, 95% CI [0.001, 0.007], p < .05) were both
significantly associated with increased Frailty index change. For the Fried
phenotype, higher baseline inflammation biomarkers were associated with
higher baseline frailty status (p < .001), but there were no significant
associations over the 12-year follow-up. Accordingly, inflammation appeared
to be associated with higher rates of frailty over time but the way in which you
measure frailty can affect this association.
The third study aimed to explore the heterogeneity of frailty trajectories and
account for the probability that not all individuals follow the same path. Using
a quadratic latent class mixed model, subpopulations of frailty trajectories
were identified over approximately 12 years in the Lothian Birth Cohort 1936.
Analyses revealed three classes of frailty trajectories which begin at different
intercepts and follow different slopes: Low (61%, n = 632), Medium (36%, n =
368), or High (3%, n = 28). Those in the Low class were younger, had higher
education, higher age 11 cognitive ability, and were from a higher social
class when compared to those in either Medium or High classes. These
findings help to demonstrate the heterogeneous nature of frailty progression
and indicate that not all older adults will follow a similar path. This has clinical
implications for identifying those on steeper trajectories and implementing
effective prevention strategies.
The fourth study shifted focus to the cognitive aspects of later life decline by
exploring the health state known as mild cognitive impairment or MCI. This
study introduced the concept and detailed how it was coded and
implemented in the Lothian Birth Cohort 1936. MCI is implemented at three
waves of the cohort at ages 76 (n = 567), 79 (n = 441), and 82 years (n =
341). In line with similar cohorts, rates of MCI showed an increase at each
wave between 76 and 82 years from 15% to 18%. Additionally, two subtypes
of MCI were derived: amnestic, which solely considered memory related
cognitive decline, and non-amnestic, which considered non-memory related
cognitive impairments (executive function, attention, language, and
visuospatial skills). These subtypes also showed increases over time in the
cohort, however, the non-amnestic subtype showed rates that were higher
than expected compared to similar cohorts. This study highlighted the
prevalence of MCI in the Lothian Birth Cohort 1936 and opened the door for
further study of cognitive ageing trajectories.
The fifth and final study considered transitions in MCI status and the factors
that may be associated with these changes in the Lothian Birth Cohort 1936.
Progressions and reversions in MCI status between the ages of 76 and 82
years were assessed. At age 76, 14% of the sample had MCI, compared to
19% at age 82. Findings showed that over the six-year period, 74% remained
cognitively healthy, 12% transitioned to MCI, 7% reverted to healthy
cognition, and 7% maintained their baseline MCI status. Multinomial logistic
regression analysis indicated that these transitions are affected by factors
including age, cardiovascular disease, and number of depressive symptoms.
This study illustrates the volatility of cognitive states in later life and highlights
several factors, including depression, which may be associated with these
changes.
This thesis provided an exploration of the ageing process by considering the
trajectories of frailty and MCI in the Lothian Birth Cohort 1936. The findings
contribute to an expanding field of longitudinal research, which hopes to
understand how health statuses like frailty and MCI change over time, and
the salient factors associated with these changes. Incremental advances like
those seen in the studies in this thesis allow for a better understanding of
how the ageing process affects us in later life, ultimately leading to better
prevention strategies and interventions that allow every individual to follow
their healthiest ageing trajectory
Heterogeneity of Frailty Trajectories and Associated Factors in the Lothian Birth Cohort 1936
INTRODUCTION: Recent research suggests that the experience of frailty progression may be heterogeneous, with latent subpopulations of older adults following distinct trajectories of frailty. We aimed to investigate this notion and determine whether certain factors are associated with the membership of these subpopulations. METHODS: Data from 5 data waves collected over 12 years in participants of the Lothian Birth Cohort 1936, aged 70 at baseline, were used to derive the frailty index (FI) (NW1 = 1,091, NW5 = 431). These were used in latent class mixed modelling to estimate subpopulations of frailty trajectories. RESULTS: A quadratic latent class mixed model found 3 distinct groupings, which followed a low (61%, n = 632), medium (36%, n = 368), or high (3%, n = 28) FI trajectory. Each grouping had different intercepts and slopes, with the high grouping following the steepest trajectory indicating a rapid increase in frailty. Findings showed that in general, those in the low grouping were younger, had higher education, higher age 11 cognitive ability, and were from a higher social class than those in the medium and high groupings. DISCUSSION/CONCLUSION: Our findings demonstrate heterogeneity in frailty trajectories over 12 years in individuals aged 70 years at baseline. Membership of higher frailty trajectory groupings was associated with lower social class, less education, and lower childhood cognitive ability, indicating the potential for future interventions to target individuals who are at the greatest risk of belonging to the high frailty trajectory. Future research is required to continue this line of inquiry by exploring other risk and protective factors, and importantly, to assess whether it is possible to realign an individual's membership to a less detrimental grouping of frailty trajectory
Inflammation as a risk factor for the development of frailty in the Lothian Birth Cohort 1936
Background
Research suggests that frailty is associated with higher inflammation levels. We investigated the longitudinal association between chronic inflammation and frailty progression.
Methods
Participants of the Lothian Birth Cohort 1936, aged 70 at baseline were tested four times over 12 years (wave 1: n = 1091, wave 4: n = 550). Frailty was assessed by; the Frailty Index at waves 1â4 and Fried phenotype at waves 1, 3 and 4. Two blood-based inflammatory biomarkers were measured at wave 1: Fibrinogen and C-reactive protein (CRP).
Results
Fully-adjusted, linear mixed effects models showed higher Fibrinogen was significantly associated with higher wave 1 Frailty Index score (β = 0.011, 95% CI[0.002,0.020], p < .05). Over 12 year follow-up, higher wave 1 CRP (β = 0.001, 95% CI[0.000,0.002], p < .05) and Fibrinogen (β = 0.004, 95% CI[0.001,0.007], p < .05) were significantly associated with increased Frailty Index change. For the Fried phenotype, wave 1 Pre-frail and Frail participants had higher CRP and Fibrinogen than Non-frail participants (p < .001). Logistic regression models calculated risk of worsening frailty over follow-up and we observed no significant association of CRP or Fibrinogen in minimally-adjusted nor fully-adjusted models.
Conclusions
Findings showed a longitudinal association of higher wave 1 CRP and Fibrinogen on worsening frailty in the Frailty Index, but not Fried Phenotype. A possible explanation for this disparity may lie in the conceptual differences between frailty measures (a biopsychosocial vs physical approach). Future research, which further explores different domains of frailty, as well the associations between improving frailty and inflammation levels, may elucidate the pathway through which inflammation influences frailty progression. This may improve earlier identification of those at high frailty risk
Impact of COVID-19 lockdown on psychosocial factors, health, and lifestyle in Scottish octogenarians:The Lothian Birth Cohort 1936 Study
BackgroundLittle is known about effects of COVID-19 lockdown on psychosocial factors, health and lifestyle in older adults, particularly those aged over 80 years, despite the risks posed by COVID-19 to this age group.MethodsLothian Birth Cohort 1936 members, residing mostly in Edinburgh and the surrounding Lothians regions in Scotland, mean age 84 years (SD = 0.3), responded to an online questionnaire in May 2020 (n = 190). We examined responses (experience and knowledge of COVID-19; adherence to guidance; impact on day-to-day living; social contact; self-reported physical and mental health; loneliness; and lifestyle) and relationships between previously-measured characteristics and questionnaire outcomes.ResultsFour respondents experienced COVID-19; most had good COVID-19 knowledge (94.7%) and found guidance easy to understand (86.3%). There were modest declines in self-reported physical and mental health, and 48.2% did less physical activity. In multivariable regression models, adherence to guidance by leaving the house less often associated with less professional occupational class (OR = 0.71, 95%CI 0.51-0.98) and poorer self-rated general health (OR = 0.62, 95%CI 0.42-0.92). Increased internet use associated with female sex (OR = 2.32, 95%CI 1.12-4.86) and higher general cognitive ability (OR = 1.53, 95%CI 1.03-2.33). Loneliness associated with living alone (OR = 0.15, 95%CI 0.07-0.31) and greater anxiety symptoms (OR = 1.76, 95%CI 0.45-1.24). COVID-19 related stress associated with lower emotional stability scores (OR = 0.40, 95%CI 0.24-0.62). Decreased physical activity associated with less professional occupational class (OR = 1.43, 95%CI 1.04-1.96), and lower general cognitive ability (OR = 0.679, 95%CI 0.491-0.931).ConclusionsCharacteristics including cognitive function, occupational class, self-rated health, anxiety, and emotional stability, may be related to risk of poorer lockdown-related psychosocial and physical outcomes