Sleep Disturbances and Cognitive Impairment in the Course of Type 2 Diabetes-A Possible Link

Intermittent hypoxia exacerbates anxiety in high-fat diet-induced diabetic mice by inhibiting TREM2-regulated IFNAR1 signaling

BACKGROUND

Type 2 diabetes mellitus (T2DM) and obstructive sleep apnea (OSA) are mutual risk factors, with both conditions inducing cognitive impairment and anxiety. However, whether OSA exacerbates cognitive impairment and anxiety in patients with T2DM remains unclear. Moreover, TREM2 upregulation has been suggested to play a protective role in attenuating microglia activation and improving synaptic function in T2DM mice. The aim of this study was to explore the regulatory mechanisms of TREM2 and the cognitive and anxiety-like behavioral changes in mice with OSA combined with T2DM.

METHODS

A T2DM with OSA model was developed by treating mice with a 60% kcal high-fat diet (HFD) combined with intermittent hypoxia (IH). Spatial learning memory capacity and anxiety in mice were investigated. Neuronal damage in the brain was determined by the quantity of synapses density, the number and morphology of brain microglia, and pro-inflammatory factors. For mechanism exploration, an in vitro model of T2DM combined with OSA was generated by co-treating microglia with high glucose (HG) and IH. Regulation of TREM2 on IFNAR1-STAT1 pathway was determined by RNA sequencing and qRT-PCR.

RESULTS

Our results showed that HFD mice exhibited significant cognitive dysfunction and anxiety-like behavior, accompanied by significant synaptic loss. Furthermore, significant activation of brain microglia and enhanced microglial phagocytosis of synapses were observed. Moreover, IH was found to significantly aggravate anxiety in the HFD mice. The mechanism of HG treatment may potentially involve the promotion of TREM2 upregulation, which in turn attenuates the proinflammatory microglia by inhibiting the IFNAR1-STAT1 pathway. Conversely, a significant reduction in TREM2 in IH-co-treated HFD mice and HG-treated microglia resulted in the further activation of the IFNAR1-STAT1 pathway and consequently increased proinflammatory microglial activation.

CONCLUSIONS

HFD upregulated the IFNAR1-STAT1 pathway and induced proinflammatory microglia, leading to synaptic damage and causing anxiety and cognitive deficits. The upregulated TREM2 inT2DM mice brain exerted a negative regulation of the IFNAR1-STAT1 pathway. Mice with T2DM combined with OSA exacerbated anxiety via the downregulation of TREM2, causing heightened IFNAR1-STAT1 pathway activation and consequently increasing proinflammatory microglia.

Association of obstructive sleep apnea and sleep quality with cognitive function: a study of middle-aged and elderly persons in India

INTRODUCTION

Symptoms of obstructive sleep apnea (OSA) and poor sleep quality affect around one in ten people in India. We aimed to determine if OSA symptoms and poor sleep quality are independently associated with cognition in middle-aged and elderly urban Indian populations.

METHODS

We studied the cross-sectional association between OSA symptoms (by Berlin Questionnaire), poor sleep quality (by Pittsburgh Sleep Quality Index), and cognitive function in adults ≥ 50 years. Using a standard neuropsychological battery for cognitive function, a G-factor was derived as the first rotated principal component assessing domains of information processing, memory, and executive function. The associations of exposures with cognitive measures were modeled using linear regression, adjusted for metabolic risk factors, lifestyle factors, and psychosocial problems, followed by stratified analysis by decadal age group.

RESULTS

A total of 7505 adults were enrolled. Excluding those with MMSE < 26 (n 710), of 6795 individuals (49.2% women), mean (SD) age 64.2 (9.0) years, 38.3% had high risk of OSA symptoms, and 15.9% had poor sleep quality. OSA symptoms were negatively associated with cognitive domains of information processing (adjusted beta coefficient of z-score - 0.02, p-value 0.006), memory (- 0.03, 0.014), and G-factor (- 0.11, 0.014) in full-model. Stratified analysis by age group showed significant adverse effects of OSA symptoms on cognition for middle-aged people (50-60 years) (- 0.26, 0.001), but not in later age groups. Poor sleep quality was also associated with lower cognitive scores for G-factor (- 0.48, < 0.001), memory (- 0.08, 0.005), and executive domains (- 0.12, < 0.001), but not with information domain.

CONCLUSION

The findings suggest that both symptoms of OSA and poor sleep quality have a direct adverse impact on cognition in an Indian setting. A modest effect of age on the relationship of OSA and cognition was also observed.

Glucose Metabolism and Cognitive Decline in Progressive Supranuclear Palsy and Corticobasal Syndrome: A Preliminary Study

Multiple studies have analyzed the possible correlations between diabetes and Alzheimer's disease. Less is known about the context of cognitive deterioration among patients with atypical Parkinsonian syndromes and glucose metabolism impairment. The aim of this study was to evaluate the association between the impaired glucose metabolism and cognitive decline among patients with progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS). The study included 22 patients with PSP and CBS with disease durations varying from 3 to 6 years. The levels of glycated hemoglobin (HbA1C), fasting blood glucose, fasting C-peptide and the presence of microalbuminuria were evaluated, and oral glucose tolerance tests (OGTT) were performed. Based on the OGTT results, the glycemic variability, mean glycemia, glycemia standard deviation (SD) and coefficient of variation (%CV) were calculated. All patients underwent a three-Tesla brain magnetic resonance (MRI) examination and neuropsychological cognitive assessment with the use of standardized scales: Montreal Cognitive Assessment (MoCA), Mini-Mental State Examination (MMSE) and Frontal Assessment Battery (FAB). A statistical analysis revealed that poor control of glycemia with high glycemic variability and increased atrophy of the medial temporal lobe among patients with PSP and CBS correlated with worse cognitive performance independent of age or sex, even among patients who did not fulfill the criteria for diabetes. The study results indicate the importance of glucose metabolism control and optimal treatment in the context of cognition maintenance among patients with PSP and CBS. Due to the relatively small number of analyzed patients, the issue requires further assessment. To the best of our knowledge, this is the first study discussing the role of glycemic variability in atypical Parkinsonian syndromes.

Potential risk factors for mild cognitive impairment among patients with type 2 diabetes experiencing hypoglycemia

AIMS

This study examined the association between hypoglycemia and mild cognitive impairment (MCI) among patients with type 2 diabetes mellitus (T2DM) and identified risk factors for MCI in patients with hypoglycemia.

METHODS

In this retrospective study, 328 patients with T2DM were screened in 2019 and followed up in 2022. Cognitive performance was assessed using the Montreal Cognitive Assessment (MoCA). The diagnosis of MCI was based on established criteria. Risk ratio (RR) with 95 % confidence intervals (CI) was calculated to estimate the risk of MCI. Univariate and multivariate logistic regression analyses were conducted to identify risk factors for MCI in those with hypoglycemia.

RESULTS

Patients with hypoglycemia had lower cognitive performance 3 years later. The RR of MCI was 2.221 (95 % CI 1.269-3.885). Multivariate logistic analysis showed that low grip strength, existing diabetic retinopathy (DR), and multiple hypoglycemia episodes were associated with higher odds of MCI in patients with hypoglycemia (adjusted odds ratio [OR] 0.909 [95 % CI 0.859-0.963]), 3.078 [95 % CI 1.158-12.358], and 4.642 [95 % CI 1.284-16.776], respectively, all P < 0.05).

CONCLUSIONS

Hypoglycemia increased MCI risk among patients with T2DM. Low grip strength, DR, and multiple hypoglycemia episodes may be potential risk factors for hypoglycemia-associated MCI.

Age-group-specific association of oral health and systemic health on cognitive function: a cross-sectional study of Korean elders

BACKGROUND

Although the importance of oral and systemic healthcare for elderly people is increasing owing to the rapid ageing of the population in South Korea, studies on the relationship between oral health, systemic health, and cognitive function, as well as on the prediction of cognitive function by oral and systemic health depending upon age groups are lacking.

METHODS

We included 5,975 out of 6,488 participants from the 8th wave of the Korean Longitudinal Study of Aging (KLoSA) panel data, divided the participants into three age groups, and performed a hierarchical multiple linear regression analysis to explain cognitive function with four types of predictors: oral health status, sociodemographic factors, objective health status, and subjective health status.

RESULTS

Oral health status was positively correlated with systemic health status and cognitive function. Of all ages over 54, cognitive function was significantly predicted by oral health variables, such as the number of functional teeth, masticatory ability, and Geriatric Oral Health Assessment Index (GOHAI); sociodemographic variables, such as age, sex, education level, and residence; and systemic health variables, such as diagnosis of diabetes mellitus, cancer or malignant tumours, cerebrovascular disease and rheumatoid arthritis, depressive symptom, and self-rated health status. Oral health variables explained cognitive function differently by age group; GOHAI appeared important predictor in the group aged < 75 years, whereas the number of functional teeth did in the group aged ≥ 75 years. Educational level, masticatory ability, depressive symptoms, and self-rated health status were pivotal factors age-independently.

CONCLUSIONS

The general and age-group-specific association between oral health, systemic health, and cognitive function were confirmed, suggesting that age-group-specific oral healthcare should be emphasized for the effective management of systemic and cognitive health in the elderly group.

Healthy lifestyle and all-cause and cause-specific dementia in individuals with type 2 diabetes and the roles of diabetes duration and insulin use in UK Biobank cohort

AIMS

To examine the effect of a healthy lifestyle score derived from seven lifestyle factors recommended by the diabetes management guidelines on all-cause and cause-specific dementia in individuals with type 2 diabetes mellitus (T2DM), and how diabetes duration and insulin use status modify their association.

MATERIALS AND METHODS

This study analysed data of 459 840 participants from the UK Biobank. We used Cox proportional hazards models to estimate hazard ratios (HRs) and 95% confidence intervals for the association of an overall healthy lifestyle score with all-cause and cause-specific dementia of Alzheimer's disease, vascular dementia and non-Alzheimer non-vascular dementia.

RESULTS

Using diabetes-free participants who scored 5-7 as the reference group, in diabetes-free participants, we observed higher healthy lifestyle score was related to lower risk of all-cause and cause-specific dementia. However, in people with T2DM, those scored 2-3, 4 and 5-7 all had around the two-time risk of all-cause dementia (HR: 2.20-2.36), while those scored 0-1 had over a three-time risk (HR: 3.14, 95% confidence interval 2.34-4.21). A dose-response trend was observed with vascular dementia (each 2-point increase: 0.75, 0.61-0.93) and no significant association with Alzheimer's disease (0.95, 0.77-1.16). The reduced risk of all-cause and cause-specific dementia with higher lifestyle score was observed in patients with a diabetes duration less than 10 years, or in patients with no insulin use.

CONCLUSION

In people with T2DM, higher healthy lifestyle score was associated with lower risk of all-cause dementia. Diabetes duration and insulin use moderated the association between healthy lifestyle score and risk of dementia.

Association of insomnia with incident chronic cognitive impairment in older adults with type 2 diabetes mellitus: A prospective study of the Hong Kong Diabetes Register

AIMS

To examine the risk association of insomnia with incident chronic cognitive impairment in older adults with type 2 diabetes mellitus (T2D).

METHODS

Between July 2010 and June 2015, patients with T2D aged ≥60 years enrolled in the Hong Kong Diabetes Register completed the Insomnia Severity Index (ISI) questionnaire. Patients were considered having insomnia if they had ISI score > 14. We prospectively followed up the cohort and censored outcome through reviewing diagnoses and clinical notes entered by attending physicians in electronic medical record to identify incident cases of mild cognitive impairment and dementia.

RESULTS

After excluding shift workers and those with established chronic cognitive impairment at baseline, we included 986 patients with T2D in this study (58.3 % men, mean age ± standard deviation: 62.5 ± 2.6 years, disease duration of diabetes: 10.7 ± 8.2 years, HbA1c: 7.4 ± 1.3 %, insulin users: 28.7 %, insomnia: 9.1 %). After a median follow-up of 7.6 (interquartile range = 2.0) years, 41 (4.2 %) developed chronic cognitive impairment. Using Cox regression analysis, insomnia (hazard ratio, HR 2.909, p = 0.012) and HbA1c ≥ 7 % (HR 2.300, p = 0.038) were positively associated with incident chronic cognitive impairment while insulin use (HR 0.309, p = 0.028) showed negative association.

CONCLUSIONS

Insomnia, suboptimal glycemic control and non-insulin use are independent risk factors for incident chronic cognitive impairment in older adults with T2D.

Sleep-associated insulin resistance promotes neurodegeneration

Lifestyle modification can lead to numerous health issues closely associated with sleep. Sleep deprivation and disturbances significantly affect inflammation, immunity, neurodegeneration, cognitive depletion, memory impairment, neuroplasticity, and insulin resistance. Sleep significantly impacts brain and memory formation, toxin excretion, hormonal function, metabolism, and motor and cognitive functions. Sleep restriction associated with insulin resistance affects these functions by interfering with the insulin signalling pathway, neurotransmission, inflammatory pathways, and plasticity of neurons. So, in this review, We discuss the evidence that suggests that neurodegeneration occurs via sleep and is associated with insulin resistance, along with the insulin signalling pathways involved in neurodegeneration and neuroplasticity, while exploring the role of hormones in these conditions.

Sleep disturbances, glycaemic control, stress, and coping among diabetic patients: A structural equation modelling approach

BACKGROUND

Sleep disturbances are more prevalent in diabetic patients than in the general population and may consequently be comorbid with hyperglycaemia.

OBJECTIVE

The two study aims were to (1) verify the factors associated with sleep disturbances and glycaemic control and (2) further understand the mediation effects of coping and social support in the relationship among stress, sleep disturbances, and glycaemic control.

METHODS

A cross-sectional study design was used. Data were collected at two metabolic clinics in southern Taiwan. The study recruited 210 patients with type II diabetes mellitus who were aged 20 years or above. Demographic information and data on stress, coping, social support, sleep disturbances, and glycaemic control were collected. The Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality, and PSQI scores >5 were considered to indicate sleep disturbances. Structural equation modelling (SEM) approaches were employed to analyse the path association for sleep disturbances in diabetic patients.

RESULTS

The mean age of the 210 participants was 61.43 (standard deviation, SD 11.41) years old, and 71.9 % reported sleep disturbances. The final path model had acceptable model fit indices. Stress perception was divided into stress perceived positively and negatively. Stress perceived positively was associated with coping (β = 0.46, p < .01) and social support (β = 0.31, p < .01), whereas stress perceived negatively was significantly associated with sleep disturbances (β = 0.40, p < .001).

CONCLUSIONS

The study shows that sleep quality is essential to glycaemic control, and stress perceived negatively might play a critical role to sleep quality.

The impact of sleep components, quality and patterns on glymphatic system functioning in healthy adults: A systematic review

OBJECTIVE

The glymphatic system is thought to be responsible for waste clearance in the brain. As it is primarily active during sleep, different components of sleep, subjective sleep quality, and sleep patterns may contribute to glymphatic functioning. This systematic review aimed at exploring the effect of sleep components, sleep quality, and sleep patterns on outcomes associated with the glymphatic system in healthy adults.

METHODS

PubMed®, Scopus, and Web of Science were searched for studies published in English until December 2021. Articles subjectively or objectively investigating sleep components (total sleep time, time in bed, sleep efficiency, sleep onset latency, wake-up after sleep onset, sleep stage, awakenings), sleep quality, or sleep pattern in healthy individuals, on outcomes associated with glymphatic system (levels of amyloid-β, tau, α-synuclein; cerebrospinal fluid, perivascular spaces; apolipoprotein E) were selected.

RESULTS

Out of 8359 records screened, 51 studies were included. Overall, contradictory findings were observed according to different sleep assessment method. The most frequently assessed sleep parameters were total sleep time, sleep quality, and sleep efficiency. No association was found between sleep efficiency and amyloid-β, and between slow-wave activity and tau. Most of the studies did not find any correlation between total sleep time and amyloid-β nor tau level. Opposing results correlated sleep quality with amyloid-β and tau.

CONCLUSIONS

This review highlighted inconsistent results across the studies; as such, the specific association between the glymphatic system and sleep parameters in healthy adults remains poorly understood. Due to the heterogeneity of sleep assessment methods and the self-reported data representing the majority of the observations, future studies with universal study design and sleep methodology in healthy individuals are advocated.

The lymphatic system: a therapeutic target for central nervous system disorders

The lymphatic vasculature forms an organized network that covers the whole body and is involved in fluid homeostasis, metabolite clearance, and immune surveillance. The recent identification of functional lymphatic vessels in the meninges of the brain and the spinal cord has provided novel insights into neurophysiology. They emerge as major pathways for fluid exchange. The abundance of immune cells in lymphatic vessels and meninges also suggests that lymphatic vessels are actively involved in neuroimmunity. The lymphatic system, through its role in the clearance of neurotoxic proteins, autoimmune cell infiltration, and the transmission of pro-inflammatory signals, participates in the pathogenesis of a variety of neurological disorders, including neurodegenerative and neuroinflammatory diseases and traumatic injury. Vascular endothelial growth factor C is the master regulator of lymphangiogenesis, a process that is critical for the maintenance of central nervous system homeostasis. In this review, we summarize current knowledge and recent advances relating to the anatomical features and immunological functions of the lymphatic system of the central nervous system and highlight its potential as a therapeutic target for neurological disorders and central nervous system repair.

Maternal sleep during pregnancy and adverse pregnancy outcomes: a systematic review and meta-analysis

AIM/INTRODUCTION

Sleep problem is an important public health concern worldwide. We conducted a meta-analysis to quantitatively evaluate whether sleep duration associated with pregnancy outcomes, and the associations were modified by important characteristics of studies.

MATERIALS AND METHODS

Basing on PubMed, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL) databases, we searched for the published literature related to maternal sleep duration and adverse pregnancy outcomes before 30 June, 2021. We conducted risk of bias assessment, subgroup analyses and sensitivity analysis. The relative risks (RR) or odds ratios (OR) with 95% confidence intervals (CI) were used to estimate the pooled effects.

RESULTS

5246 references were identified through databases searching, 41 studies were included in the study. Pregnant with short sleep duration had 1.81 times (95% CI 1.35-2.44, P < 0.001) risk of gestational diabetes mellitus (GDM). The association between short sleep duration and the risk of gestational hypertension (GH), cesarean section (CS), low birthweight (LBW), preterm birth (PTB) and small for gestational age (SGA) were not significant (P > 0.05). Furthermore, long sleep duration was significantly correlated with GDM (OR 1.24. 95% CI 1.12-1.36, P < 0.001) and CS (OR 1.13. 95% CI 1.04-1.22, P = 0.004), while long sleep duration was not linked with GH, LBW, PTB and SGA (P > 0.05).

CONCLUSIONS

Short / long sleep duration appeared to be associated with adverse pregnancy outcome, specifically with an increased risk of GDM. Sleep should be systematically screened in the obstetric population.

Association of cognitive impairment with sleep quality, depression and cardiometabolic risk factors in individuals with type 2 diabetes mellitus: A cross sectional study

AIM

The aim of this study was to evaluate the association of cognitive impairment with sleep quality, depression, and cardiometabolic risk factors among participants with type 2 diabetes mellitus.

METHODS

Subjects underwent clinical interview to capture socio-demographic details, medical history, sleep quality, presence of depression, along with anthropometric and biochemical measurements. A detailed neuropsychological assessment [Montreal cognitive assessment scale (MoCA), Trail making A and B, Digit span, Spatial span, Letter Number Sequencing] was done. Cognitive impairment was defined as MoCA score of <23.

RESULTS

Participants (n=250, 50% women, 63.6% middle-age) had a mean (±SD) age of 53.6 (±9.1) years and HbA1c of 55.1±6.8mmol/mol (7.2±0.6%). Cognitive impairment was present in 57 (22.8%) participants. In the middle-age subgroup, cognitive impairment was higher (23.9%) than those in the fourth decade (6.3%), but comparable (24.0%) to the older age (60-70years) individuals. Diabetes-related vascular complications [Odds ratio (95% CI) 2.03 (1.05, 3.94)]; hypertension [2.00 (1.04, 3.84)], depression [2.37 (1.24, 4.55)] and lower education [2.73 (1.42, 5.23)] had a significant association with cognitive impairment on multivariate logistic regression analysis.

CONCLUSION

The high burden of cognitive impairment calls for an urgent need to establish longitudinal cohorts in midlife to understand this population's cognitive trajectories and see the influence of various bio-psychosocial variables.

Health Science Community Will Miss This Bright and Uniting Star: In Memory of Professor Gjumrakch Aliev, M.D, Ph.D

It is with deep sadness that we offer our memorial on the unexpected demise of our dear colleague, Professor Gjumrakch Aliev [...].

Effectiveness of acceptance and commitment therapy (ACT) on depression and sleep quality in painful diabetic neuropathy: a randomized clinical trial

Background

Neuropathic pain is a complicated phenomenon in patients with diabetes. These patients have many problems, especially depression and Sleep disturbance. This study aimed to assess the effectiveness of Acceptance and Commitment Therapy on depression and Sleep disturbance in patients with painful diabetic neuropathy.

Methods

The current paper was conducted according to the clinical trial method with 50 participants. Participants were separated into intervention and control groups randomly. Based on the diagnosis of neurologists, all participants received standard medications to regulate neuropathic pain. The intervention group received ACT for eight sessions. The results were evaluated in the pre-test, post-test, and follow-up. The tools used were the Pittsburgh sleep quality index (PSQI) and Beck's depression inventory. Statistical analysis includes descriptive statistics, and repeated-measures (ANOVA) conducted by SPSS (version 26) software. Results: Results showed that in the intervention group, the treatment led to improved depressive symptoms (F = 6.81, P < 0.05). Besides, for sleep quality, treatment in all subscales, except for the Hypnotic medicine subscale, significantly improved the intervention group's situations. It was also observed that the overall quality of sleep in the ACT group showed a more significant improvement (P < 0.05). All the above results remained the same until the end of the follow-up period (P < 0.05).

Conclusion

ACT, as a complementary treatment, can improve the psychiatric symptoms and problems in people with neuropathic pain. Therefore, it is necessary to include psychotherapy services along with medical treatment in outpatient and hospitalization units.

Trial registration number

IRCT201802050388630N4. Registered in 02/05/2018.