Page 78 - AN-2-3

Advanced Neurology Sleep and lifestyle factors in young adults with childhood TBI

sleep quality and chronotype did not differ between the sleep by the brain. We propose that the relationship
TBI and controls. This latter finding aligns with studies between tobacco use and poor sleep quality in these young
showing no differences in chronotype between adults who adults with childhood TBI may be related to a combination
sustained TBI in adulthood and controls . Eveningness of these clinical and neurobiological factors, which can be
[39]
has been previously associated with increased insomnia examined in future studies.
symptoms [28,40] , poor sleep quality, and increased sleep debt Poor objective sleep efficiency was significantly
[41]
(especially during week days) in healthy young adults , associated with being a parent in the whole TBI group
but data on the relationship between chronotype and sleep and in the subsample that reported poor objective sleep
quality in TBI are limited. Chronotype is a behavioral efficiency (<85% sleep efficiency). In this study, all
phenotype ensuing from the two processes that regulate participants with children were in the TBI group and 92%
sleep and wake: The internal circadian clock and sleep of them had children below 8 years old, suggesting that
homeostasis . Evening chronotype is due to either a their poor sleep efficiency may be related to involvement
[42]
later circadian clock phase (later sleep and wake times),
a slower homeostatic build-up of sleep pressure (causing with their children at night. Studies involving typically
a naturally low tendency of falling asleep early), or both, developing adults have reported that sleep quality can
which are all possible explanations for the increased risk be affected in parent with younger children in instances
of poor sleep quality in our TBI participants with evening where the child has sleep problems, family environment
[43]
chronotype . A previous study in adults with TBI found is stressful, parent is too involved in soothing the child
no conclusive objective evidence of shift in circadian timing at bedtime and during night awakenings, and parent
[47-50]
of sleep following TBI , but the question of whether brain has irregular routines . We hence propose that the
[39]
disruptions caused by childhood TBI contributes to shift in significant relationship identified between being a parent
circadian timing or reduced homeostatic sleep regulation and poor objective sleep efficiency in this sample is
is a question for further research. potentially due to some of these reasons.
Tobacco use in the past 2 months was also significantly Alcohol use in the last month was also significantly
associated with poor subjective sleep quality in the whole associated with poor sleep efficiency in the young adults with
TBI group, and in TBI participants who reported poor TBI who presented with poor sleep efficiency. This finding
subjective sleep quality. This resonates with reports on the resonates with several studies that have associated alcohol
negative impact of smoking on sleep in population-based consumption with poor sleep quality [51,52] . Although many
healthy smokers . Reviews on this relationship have people use alcohol for its sleep-promoting effects, alcohol
[27]
indicated that cigarette smokers are more likely to experience acts as a sedative and affects several neurotransmitter
difficulty initiating and maintaining sleep, breathing- systems important for sleep regulation (e.g., GABAergic
[53]
related sleep problems, and daytime sleepiness , and are systems) . Alcohol reduces sleep quality through several
[44]
about 47% more likely to experience sleep disturbance mechanisms, including reducing sleep duration, increasing
than non-smokers . Although the proportion of tobacco risk of breathing-related sleep problems, disrupting
[45]
users were not significantly different between our TBI sleep architecture early in the night (when blood alcohol
and TDC groups, this significant relationship was only levels are high), and causing insomnia and abnormalities
found in the TBI group, suggesting greater vulnerability of circadian rhythms [51,53] . Our finding regarding this
in this group to the negative effects of smoking on sleep relationship was present only in the young adults with
quality. Clinically, smoking is associated with managing TBI who had poor sleep efficiency (67% of TBI group), of
pain and depression, increased risk of snoring (e.g., due to which 83% endorsed using alcohol in the past 2 months.
upper airway inflammation), increased arousal, increased We propose that this finding indicates a greater effect of
night wakening (to sooth nicotine cravings especially in alcohol on this subgroup, potentially due to the negative
heavy smokers), and poor sleep hygiene (especially when impact of alcohol on their already vulnerable brain. The
people smoke close to bedtime) [44,45] ; all of which may question of whether alcohol affects sleep efficiency in early
have impacted subjective sleep quality in our TBI group. TBI survivors through known mechanisms such as reduced
From a neurobiological perspective, the relationship melatonin secretion , disrupted homeostatic regulation,
[53]
identified in this TBI group may be because this group or reduced neural sleep regulation remain open for
[51]
is more vulnerable to the known toxic effects of cigarette future investigation.
smoking on the brain (including increased oxidative stress, 4.1. Study limitations
inflammation, and atherosclerosis) . This is likely because
[46]
TBI may have interrupted the development of their sleep- Some limitations of the present study should be considered:
related brain areas or hindered the effective regulation of (I) The small sample size used in this study limits the

Volume 2 Issue 3 (2023) 8 https://doi.org/10.36922/an.0876