Kelly, Rachael (2022) Evaluating Weekly Circadian Misalignment and the Role it Plays in Type 2 Diabetes Disease Management. PhD thesis, National University of Ireland Maynooth.
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Abstract
Background
Type 2 diabetes (T2D) is a chronic condition and poorer glycemic control in T2D
increases the risk of debilitating complications. Sleep and sleep timing have been
implicated in both T2D disease risk and management. Chronotype, the behavioural
manifestation of phase of entrainment, and social jetlag (SJL), the misalignment
between external social time and internal biological time, have been associated with
poorer metabolic health. The primary aim of this thesis was to determine how phase
of entrainment and living against the circadian clock can influence T2D disease
management, with the intention of guiding potential behavioural or educational
interventions to improve T2D disease management.
Methods and Results
Chapter 2 was a cross-sectional study which revealed that SJL predicted poorer
glycemic control in participants with T2D, while chronotype and personality factors
were not significant predictors. A novel interaction between chronotype, SJL and
glycemic control was identified; a positive association between later chronotype and
HbA1c was only identified in those with the most SJL.
Chapter 3 assessed additional measures of sleep timing variability and metabolic
health. This work demonstrated that many measures of circadian misalignment may
not measure the same construct. SJL and sleep end variability were moderately
associated; however, variability in midsleep, sleep onset and actual sleep duration
were not associated with SJL. Furthermore, variability in midsleep, sleep onset and
actual sleep duration showed an inverse association with HbA1c in a group of people
with well controlled diabetes, suggesting that lower variability was associated with
higher HbA1c levels. Why exactly this occurs is unknown, it may be reliant on the
characteristics of the sample.
Chapter 4 included two studies which investigated the association between SJL and
stress. Study 1 was a cross-sectional study which revealed that SJL was not a
significant predictor of general perceived stress or work-related psychosocial stress.
Study 2 was an experimental study which demonstrated that SJL did not result in
greater reactivity to a physiological stressor. These studies combined suggest that
stress does not mediate the effect of SJL on glycemic control or other indicators of
metabolic health.
Chapter 5 described weekly sleep offset differences in a large sample of UK adults.
Interestingly, older participants who were not working displayed weekday to weekend
day sleep offset differences, albeit to a lesser degree than younger participants.
Chapter 6 qualitatively assessed sleep timing among participants with T2D who were
either retired or not currently working. Reducing circadian misalignment may be more
feasible among individuals without the daily constraints that come with a regular work
schedule. Reflexive thematic analysis of semi-structured interviews revealed that
social factors such as quality of TV programs and a desire to maintain a sense of
normality when not working led to fluctuating sleeping patterns. Derived zeitgebers
from family members also played a role. Those with consistent sleeping patterns had
formed healthy habits, had ownership over the environment before bed and good sleep
hygiene. They also had some unavoidable curtailments every morning that helped
them to form this schedule.
Conclusion
The current findings highlight how common circadian misalignment is and how it may
impact T2D management. The findings also provide some rich information on what
factors can influence sleep timing beyond work schedules. This paves the way for
developing some behavioural and psychoeducational interventions designed to reduce
circadian misalignment among those with T2D. This could then reduce the risk of
debilitating complications.
Item Type: | Thesis (PhD) |
---|---|
Keywords: | Evaluating; Weekly Circadian Misalignment; Role; Type 2 Diabetes; Disease Management; |
Academic Unit: | Faculty of Science and Engineering > Psychology |
Item ID: | 16550 |
Depositing User: | IR eTheses |
Date Deposited: | 20 Sep 2022 14:44 |
URI: | https://mural.maynoothuniversity.ie/id/eprint/16550 |
Use Licence: | This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here |
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