Effects of sleep restriction on subjective and physiological variables in middle-aged Korean adults: an intervention study

Association of the Korean Healthy Eating Index and sleep duration with prediabetes in middle-aged adults

BACKGROUND/OBJECTIVES

Sleep duration and diet quality are reportedly associated with the risk of diabetes. This study aimed to examine the risk of diabetes according to sleep duration and diet quality in middle-aged Koreans.

SUBJECTS/METHODS

Using the Korea National Health and Nutrition Examination Survey 2019-2020, raw data from 2,934 participants aged 40-64 yrs (1,090 men and 1,844 women) who were not diagnosed with type 2 diabetes were analyzed. With a sleep duration of 7-7.9 h per night as the referent category, diet quality was assessed using the Korean Healthy Eating Index (KHEI), which comprises adequacy, moderation, and energy balance.

RESULTS

The study results showed that individuals with a short sleep duration had significantly higher blood glucose (P = 0.034) and HbA1c levels (P < 0.001) than those had by individuals with a sleep duration of 7-7.9 h. Within the group with a sleep duration of 7-7.9 h, the lowest quintile of the KHEI score had a significantly higher risk of prediabetes than that had by the highest quintile of the KHEI score (Model 1: odds ratio [OR], 1.775; 95% confidence interval [CI], 1.072-2.939; P < 0.05 and Model 2: OR, 1.731; 95% CI, 1.040-2.882; P < 0.05).

CONCLUSION

Our findings suggest that achieving the sleep duration of 7-7.9 h and eating good diet are associated with the lowest risk of prediabetes. We recommend that the results of this study be used to educate adults aged 40-64 yrs on diet and lifestyle habits to prevent diabetes.

Impact of sleep restriction on biomarkers of thyroid function: Two pooled randomized trials

BACKGROUND

Chronic, mildly insufficient sleep is associated with increased cardiometabolic risk, but whether the regulation of thyroid hormones and related growth factors are mechanisms of this association is unclear. We investigated whether 6 wk of mild sleep restriction (SR) alters levels of free thyroxine (FT4), thyroid stimulating hormone (TSH), and fibroblast growth factor-21 (FGF-21), a modulator of FT4, in adults with adequate habitual sleep (AS; 7-9 h/night).

METHODS

Healthy adults participated in one of two randomized, crossover studies with identical 6-wk intervention phases: AS and SR (1.5 h/night < AS). Fasted blood samples were collected at baseline and endpoint of each phase. Outcomes were concentrations of FT4, TSH, and FGF-21 (women only). Linear mixed models tested the effects of SR vs AS on the outcomes, adjusting for baseline levels, week, sex, and sex-by-condition interaction.

RESULTS

Thirty participants (20 women; 73% racial/ethnic minority; age 21-64 y [M±SD = 36.2 ± 12.8 y]) were included. In the full sample, no effects of SR on FT4 (β±SE = 0.02 ± 0.04, p = 0.654) or TSH (β±SE = -0.02 ± 0.04, p = 0.650) were observed; however, there were sex-by-condition interactions for both FT4 (p-interaction = 0.056) and TSH (p-interaction = 0.049). In sex-stratified analyses, TSH was reduced in SR vs. AS in women (β±SE = -0.11 ± 0.04, p = 0.011, Cohen's f2 = 0.55) but not men (β±SE = 0.09 ± 0.08, p = 0.261). Among women (n = 17), FGF-21 was not significantly different between conditions (β±SE = 8.51 ± 17.70, p = 0.638).

CONCLUSION

Prolonged mild SR reduces TSH in women, whereas FT4 and FGF-21 remain unaffected compared with AS. If sustained, disruptions to the thyrotropic axis in women may contribute to their more pronounced cardiometabolic risk in response to SR compared with men.

The effects of sustained mild sleep restriction on stress and distress among healthy adults: Findings from two randomized crossover studies

OBJECTIVE/BACKGROUND

Experimental studies suggest that sleep loss affects psychological outcomes. However, most studies focus on acute severe in-laboratory sleep restriction, with limited ecological validity. This study examines the impact of sustained mild sleep restriction (SR) on stress and distress among healthy adults in a naturalistic home environment.

PATIENTS/METHODS

We analyzed data from two randomized crossover studies. Individuals who regularly slept 7-9 h/night completed two 6-wk intervention phases separated by a 6-wk washout: habitual sleep (HS: maintenance of habitual bed and wake times) and SR (delayed bedtime by 1.5 h/night and maintenance of habitual wake time). Adherence to sleep duration requirements was verified with wrist actigraphy and daily sleep diaries during each intervention phase. Measures of perceived stress, subjective anxiety, subjective depression, rumination, and cortisol were collected at baseline and endpoint of each intervention phase.

RESULTS

Sixty-two participants (age 36.4 ± 14.0 y, 85.5 % women, 63.3 % racial/ethnic minority) were included in our analyses. Mean total sleep time was 7.4 ± 0.4 h/night during HS and 6.2 ± 0.4 h/night during SR (p < 0.001). Higher perceived stress (3.6 ± 1.0, p = 0.0007) and subjective anxiety (1.1 ± 0.5, p = 0.039) were observed after SR compared to HS. No effect of sleep condition was observed on subjective depression, rumination, and cortisol.

CONCLUSIONS

Our findings suggest that prolonged mildly insufficient sleep, similar to what commonly experienced in the real world, can lead to increased perceived stress and subjective anxiety in healthy adults. Addressing sleep loss, even if mild, should be a key component of interventions aimed at promoting mental health in the general population.

Is there any association between sleep disorder and temporomandibular joint dysfunction in adults? - A systematic review

OBJECTIVE

To answer the question, "Is there any association between sleep disorder and temporomandibular joint dysfunction (TMD) in adults?"

METHODS

This study followed PRISMA guidelines and was registered in PROSPERO. As eligibility criteria, observational studies that evaluated the association between sleep disorder and TMD were included. Exclusion criteria included a) studies that evaluated sleep quality and not the association of sleep disorders with TMD, b) experimental studies, book chapters, conference proceedings, and systematic reviews. The Joanna Briggs Institute tool was used to assess the risk of bias.

RESULTS

In the literature search, 3425 articles were found. After the exclusion of duplicates, 2752 were selected for reading the title and abstract, of which 26 were read in full, and 18 met eligibility criteria.

CONCLUSION

The association of sleep bruxism with TMD is controversial. While, for obstructive sleep apnea, insomnia, snoring, and gastroesophageal reflux, the analyzed studies showed a positive association.

Partial sleep restriction-induced changes in stress, quality of life, and lipid metabolism in relation to cold hypersensitivity: A before-and-after intervention study

Sleep disturbances are associated with cold hypersensitivity (CH) and characterized by excessive cold sensation in specific body parts and cold thermal discomfort. This study investigated the effects of short-term sleep restriction followed by a recovery phase on subjective health status, inflammation, and lipid metabolism in different types of CH. A total of 118 healthy adults aged 35 to 44 years without sleep disturbances were enrolled. Participants underwent 4-hour sleep restrictions per day for 3 days at a hospital and then returned to their daily lives for 4 days of rest. CH was assessed using a structured questionnaire with eight characteristic symptoms. A questionnaire and blood tests were administered baseline, after sleep restriction, and follow-up to assess cortisol, lipid profiles, and self-reported stress and quality of life (QOL). Participants were divided into CH (44.1%) and non-CH (55.9%) groups. The CH group showed increased stress, impaired QOL, and decreased low-density lipoprotein-cholesterol (LDL-C) levels compared to the non-CH group after sleep restriction. The variance for QOL (effect size = 0.07), subjective stress (effect size = 0.053), and LDL-C (effect size = 0.029) among time points depended on the group. Short-term sleep restriction was associated with deterioration of subjective health and reduced lipid metabolism; such changes were more evident in the CH group. Our findings suggest the need to consider an individual's CH status to assess the clinical risk associated with insufficient sleep.

Cortisol and C-Reactive Protein Vary During Sleep Loss and Recovery but Are Not Markers of Neurobehavioral Resilience

Cortisol and C-reactive protein (CRP) typically change during total sleep deprivation (TSD) and psychological stress; however, it remains unknown whether these biological markers can differentiate robust individual differences in neurobehavioral performance and self-rated sleepiness resulting from these stressors. Additionally, little is known about cortisol and CRP recovery after TSD. In our study, 32 healthy adults (ages 27-53; mean ± SD, 35.1 ± 7.1 years; 14 females) participated in a highly controlled 5-day experiment in the Human Exploration Research Analog (HERA), a high-fidelity National Aeronautics and Space Administration (NASA) space analog isolation facility, consisting of two baseline nights, 39 h TSD, and two recovery nights. Psychological stress was induced by a modified Trier Social Stress Test (TSST) on the afternoon of TSD. Salivary cortisol and plasma CRP were obtained at six time points, before (pre-study), during [baseline, the morning of TSD (TSD AM), the afternoon of TSD (TSD PM), and recovery], and after (post-study) the experiment. A neurobehavioral test battery, including measures of behavioral attention and cognitive throughput, and a self-report measure of sleepiness, was administered 11 times. Resilient and vulnerable groups were defined by a median split on the average TSD performance or sleepiness score. Low and high pre-study cortisol and CRP were defined by a median split on respective values at pre-study. Cortisol and CRP both changed significantly across the study, with cortisol, but not CRP, increasing during TSD. During recovery, cortisol levels did not return to pre-TSD levels, whereas CRP levels did not differ from baseline. When sex was added as a between-subject factor, the time × sex interaction was significant for cortisol. Resilient and vulnerable groups did not differ in cortisol and CRP, and low and high pre-study cortisol/CRP groups did not differ on performance tasks or self-reported sleepiness. Thus, both cortisol and CRP reliably changed in a normal, healthy population as a result of sleep loss; however, cortisol and CRP were not markers of neurobehavioral resilience to TSD and stress in this study.

Comparison of longitudinal diary and actigraphy-assessed sleep in pregnant women

STUDY OBJECTIVES

Various methods are employed to assess sleep in pregnant women, including self-report, sleep diary, and actigraphy. Unfortunately, the data are often contradictory, and interpretations are often inconsistent. The current aims are to compare subjective and objective sleep data in pregnant women collected longitudinally in early pregnancy.

METHODS

In this secondary analysis of 104 pregnant women, sleep was collected via diary and actigraphy for 14 days during three separate occasions (10-12 weeks; 14-16 weeks; and 18-20 weeks). Sleep variables included wake after sleep onset (WASO), sleep efficiency (SE), bedtime/lights out, sleep onset latency (SL), and total sleep duration (TST). Repeated measures ANOVAs compared each sleep variable across Time and by Method of data collection, while controlling for parity and daytime naps.

RESULTS

Significant differences were noted for only the method of data collection for sleep component studied for WASO, F (1, 98) = 147.20, p < 0.001; SE, F (1, 98) = 129.41, p < 0.001); bedtime/lights out, F (1, 103) = 5.33, p < 0.05); and sleep duration, F (1, 104) = 182.75, p < 0.001). Significant variation was not seen in any variable across time-period.

CONCLUSIONS

There are substantial discrepancies between diary- and actigraphy-assessed sleep measures in pregnant women which is in alignment with previous literature. These data highlight that these methodologies assess different constructs. We contend that these data may be useful as a reference to compare high-risk women or those with sleep disorders. Using a multi-modal approach to identify sleep disturbance in pregnancy is likely a more clinically useful option.

Effect of Ashwagandha (Withania somnifera) extract on sleep: A systematic review and meta-analysis

OBJECTIVE

To determine the effect of Ashwagandha extract on sleep.

METHODS

A comprehensive search was conducted in CENTRAL, MEDLINE, SCOPUS, Google Scholars, World Health Organization Trials Portal, ClinicalTrials.gov, Clinical Trial Registry of India, and AYUSH Research Portal for all appropriate trials. Randomized controlled trials that examined the effect of Ashwagandha extract versus placebo on sleep in human participants 18 years old and above were considered. Two authors independently read all trials and independently extracted all relevant data. The primary outcomes were sleep quantity and sleep quality. The secondary outcomes were mental alertness on rising, anxiety level, and quality of life.

RESULTS

A total of five randomized controlled trials containing 400 participants were analyzed. Ashwagandha extract exhibited a small but significant effect on overall sleep (Standardized Mean Difference -0.59; 95% Confidence Interval -0.75 to -0.42; I2 =  62%). The effects on sleep were more prominent in the subgroup of adults diagnosed with insomnia, treatment dosage ≥600 mg/day, and treatment duration ≥8 weeks. Ashwagandha extract was also found to improve mental alertness on rising and anxiety level, but no significant effect on quality of life. No serious side effects were reported.

CONCLUSION

Ashwagandha extract appears to has a beneficial effect in improving sleep in adults. However, data on the serious adverse effects of Ashwagandha extract are limited, and more safety data would be needed to assess whether it would be safe for long-term use.

Stress-Related Amygdala Metabolic Activity Is Associated With Low Bone Mineral Density in Postmenopausal Women: A Pilot 18F-FDG PET/CT Study

BACKGROUND

Psychological stress is associated with postmenopausal osteoporosis. However, the underlying mechanism of stress-related brain neural activity with osteoporosis is not fully elucidated. ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) is an established method to evaluate the metabolic activity of brain amygdala, a region involved in stress. We aimed to evaluate the relationship between metabolic activity of amygdala (AmygA) and osteoporosis in postmenopausal women.

MATERIALS AND METHODS

A total of 115 postmenopausal women who underwent ¹⁸F-FDG PET/CT and dual-energy X-ray absorptiometry for routine health screening were enrolled in this study. AmygA was defined as the maximum standardized uptake value (SUVmax) of amygdala divided by the mean SUV of temporal lobe. The levels of psychological stress were measured using the Psychosocial Well-being Index-Short Form (PWI-SF).

RESULTS

The participants with osteoporosis exhibited significantly higher AmygA than without osteoporosis (0.81 ± 0.16 vs. 0.61 ± 0.13, p < 0.001). The AmygA value of 0.69 was suggested as an optimal cut-off value to identify participant with osteoporosis (sensitivity; 79.1%, specificity; 83.3%, area under the curve; 0.841, p < 0.001). Furthermore, AmygA showed significant association with osteoporosis in postmenopausal woman by multivariate analysis. Psychological stress scale (PWI-SF) was well correlated with AmygA and AmygA was highest in high stress risk-, intermediate in moderate stress risk-, and lowest in healthy group.

CONCLUSIONS

AmygA measured by ¹⁸F-FDG PET/CT is associated with osteoporosis in postmenopausal women. Our results provide the possibility that stress-related neurobiological activity involving amygdala is linked with postmenopausal osteoporosis.

Comparison of a Novel Muscle Training Device with Conventional Rehabilitation Training in Motor Dysfunction of Lower Limb Patients: A Pilot Study

BACKGROUND

Postoperative functional training for fracture or osteoarthritis is mainly focused on functional self-exercise, which aims to recover the function of the lower limbs.

PURPOSE

To compare the function and life quality recovery in patients with fracture or arthritis treated with novel muscle training device (NMT) or conventional rehabilitation training (CRT) following surgery.

PATIENTS AND METHODS

A total of 32 fracture patients were randomly divided into the NMT or the CRT groups. The evaluation was performed on the first and 7th day after surgery. The outcome measurements included the incidence of foot drop, Deep Vein Thrombosis and pressure ulcers, Hospital for Special Surgery knee score (HSS scores), pain scores for the Visual Analogue Scale (Pain scores for VAS), Zung self-rating anxiety scale (SAS), Pittsburgh sleep quality index (PSQI) and the Barthel Index score.

RESULTS

The comparison of the change scores between the two groups indicated significant differences on day 7 following surgery in the Barthel Index score (P<0.01). The Pain scores for VAS between the two groups indicated a significant difference (P<0.05, U=20.0). The HSS scores between the two groups indicated a significant difference (P<0.05, U=19.0). The HSS scores exhibited a highly significant difference in the NMT group (P<0.01). The Mann-Whitney test was used to analyze the various components of the HSS scores. The comparison of the change scores on the function between the two groups indicated a significant difference (P<0.05). The Range of Motion difference between groups exhibited highly significant differences (P<0.01).

CONCLUSION

The novel muscle training device positively influenced the decrease in pain score, which resulted in a range increase of knee joint movement and a significant overall improvement in motion.