Diabetes mellitus and risk of dementia: A meta-analysis of prospective observational studies

Comparison of cognitive status of diabetic and non-diabetic elderly in the last ten years in primary health care in Iran

Introduction. Cognitive disorders and chronic diseases such as diabetes are common problems of aging. The aim of this study was to determine and compare the cognitive status of diabetic and non-diabetic elderly in the past ten years in primary health care in Iran. Method: This cross-sectional study was performed on people aged 60 years and older in Kerman, Iran in 2020. In total, this study was performed on 200 patients (100 diabetic and 100 non-diabetic) meeting inclusion criteria. The Short Mental Status Questionnaire (MMSE) and The Informant Questionnaire for Cognitive Decline in the Elderly (IQCODE) were used to assess cognitive function. The validity and reliability of the questionnaires were confirmed in this study. Data were analyzed using Chi-square, T-test, and ANOVA analysis in SPSS 21 software. Results. The results showed that there was a statistically significant difference between diabetic and non-diabetic groups in the current cognitive status and cognitive status in the last ten years. The mean scores of cognitive function from the short mental status questionnaire in the diabetic group were lower than in the non-diabetic group (p = 0.001). The mean scores of the cognitive deficit screening questionnaire in diabetic elderly were higher than in non-diabetic elderly (p < 0.001). Conclusion. Based on the results of this study, health care providers and family physicians should focus on controlling diabetes and identifying any cognitive impairment in the early stages of comprehensive care of diabetic patients.

4. Comprehensive Medical Evaluation and Assessment of Comorbidities: Standards of Medical Care in Diabetes-2022

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee (https://doi.org/10.2337/dc22-SPPC), are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction (https://doi.org/10.2337/dc22-SINT). Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

The Ketogenic Diet and Alzheimer's Disease

INTRODUCTION

Alzheimer's disease (AD) is a progressive neurodegenerative disease that is the most common form of dementia. There are currently FDA-approved symptomatic therapies for AD and a recently approved, potentially disease-modifying drug, Aducanumab; however, there are no curative or preventative therapies. Research suggests that diet may play a role in AD, but it is inconclusive relative to which dietary approach provides the most neuroprotective effects. There are other life-style approaches that have been found to possibly play a role in AD prevention/treatment. These include exercise, brain training, and social interaction. A combined approach may be more effective than any one modality alone. The ketogenic diet (KD) is one specific diet that has been studied vis a vis neurodegenerative diseases. Similar benefits to those of a KD can also be achieved through consuming a normal diet and supplementing with ketogenic agents. The purpose of this review is to compare the methods of inducing hyperketonemia and their impact on AD prevention/treatment, as well as to explore the possible benefits of a combined approach.

METHODS

The PubMed database was searched for clinical trials and randomized, controlled trials involving the KD or exogenous ketone administration and AD. Key search terms used included "ketogenic diet and Alzheimer's disease," "ketosis and Alzheimer's disease," "MCT and Alzheimer's disease," and "exercise and diet and Alzheimer's disease." Only studies involving patients diagnosed with AD were included in this paper, but for the combined approach section, studies included patients diagnosed with MCI due to a paucity of combined approach studies involving AD patients alone.

RESULTS

There is evidence that the KD and exogenous ketone supplementation may provide treatment benefits in AD patients. It is unclear whether one method is better than the other. The specific food composition of the KD should be considered, because certain types of fat sources are healthier than others. Many forms of the KD require strict monitoring of carbohydrate intake, which would often fall under the responsibility of the caregiver. Future studies may be more feasible in an institutional setting, where it would be easier to administer and to monitor a dietary protocol. Exogenous supplementation may be more likely to be adhered to as a long-term treatment, because the dietary changes are not as drastic. A multidomain approach may be the most effective in possibly preventing/delaying AD and in improving/stabilizing and possibly slowing disease progression in those with AD.

CONCLUSION

Most current studies are small, often uncontrolled, and only look at the short-term effects of ketosis on cognition. Large, long-term, randomized, controlled trials relative to the impact of the KD in patients with cognitive impairment and AD are lacking and thus needed. Combined approaches may prove to be more beneficial in possibly preventing/delaying AD and in improving/stabilizing and possibly slowing disease progression in those with MCI or AD. Future research should investigate the effect of additional combined approaches relative to neurocognitive decline in AD patients.

Dementia risk reduction: why haven't the pharmacological risk reduction trials worked? An in-depth exploration of seven established risk factors

Identifying the leading health and lifestyle factors for the risk of incident dementia and Alzheimer's disease has yet to translate to risk reduction. To understand why, we examined the discrepancies between observational and clinical trial evidence for seven modifiable risk factors: type 2 diabetes, dyslipidemia, hypertension, estrogens, inflammation, omega-3 fatty acids, and hyperhomocysteinemia. Sample heterogeneity and paucity of intervention details (dose, timing, formulation) were common themes. Epidemiological evidence is more mature for some interventions (eg, non-steroidal anti-inflammatory drugs [NSAIDs]) than others. Trial data are promising for anti-hypertensives and B vitamin supplementation. Taken together, these risk factors highlight a future need for more targeted sample selection in clinical trials, a better understanding of interventions, and deeper analysis of existing data.

Adropin transgenesis improves recognition memory in diet-induced obese LDLR-deficient C57BL/6J mice

Obesity-related metabolic dysregulation causes mild cognitive impairment and increased risk for dementia. We used an LDLR-deficient C57BL/6J mouse model (LDLRKO) to investigate whether adropin, a neuropeptide linked to neurodegenerative diseases, improves cognitive function in situations of metabolic dysregulation. Adropin transgenic mice (AdrTG) were crossed with LDLRKO; male and female progeny were fed a high fat diet for 3-months. Male chow-fed wild type (WT) mice were used as controls. Diet-induced obesity and LDLR-deficiency caused severe dyslipidemia, irrespective of sex. The AdrTG prevented reduced adropin protein levels in LDLRKO cortex. In males, metabolic dysregulation and AdrTG genotype significantly and bi-directionally affected performance in the novel object recognition (NOR) test, a declarative hippocampal memory task (discrimination index mean ± SE for WT, 0.02 ± 0.088; LDLRKO, -0.115 ± 0.077; AdrTG;LDLRKO, 0.265 ± 0.078; genotype effect, p = 0.009; LDLRKO vs. AdrTG;LDLRKO, P < 0.05). A 2-way ANOVA (fixed variables: sex, AdrTG genotype) indicated a highly significant effect of AdrTG (P = 0.003). The impact of the diet-genotype interaction on the male mouse brain was investigated using RNA-seq. Gene-ontology analysis of transcripts showing fold-changes of>1.3 or <-1.3 (P < 0.05) indicated metabolic dysregulation affected gene networks involved in intercellular/neuronal signaling, immune processes, angiogenesis, and extracellular matrix organization. The AdrTG selectively attenuated the impact of metabolic dysregulation on intercellular/neuronal signaling pathways. Intercellular/neuronal signaling pathways were also the predominant processes overrepresented when directly comparing AdrTG;LDLRKO with LDRKO. In summary, adropin overexpression improves cognitive function in severe metabolic dysregulation through pathways related to cell-cell communication and neuronal processes, and independently of preventing inflammatory responses.

Thromboxane A2 synthase inhibition ameliorates endothelial dysfunction, memory deficits, oxidative stress and neuroinflammation in rat model of streptozotocin diabetes induced dementia

RATIONALE

Vascular dementia (VaD) is the second leading cause of dementia worldwide. It is very important to find the possible pharmacological agents which may be useful in management and therapy of VaD.

OBJECTIVES

The present study investigates the effect of ozagrel, a selective thromboxane A2 (TXA2) synthase inhibitor, in a rat model of VaD.

METHODS

Single intraperitoneal injection of streptozotocin [STZ, (50 mg/kg)] was administered to Wistar rats to induced diabetes-associated vascular endothelial dysfunction and memory impairment. Morris water maze (MWM) test was employed to assess learning and memory. Endothelial dysfunction was assessed in the isolated aorta by observing endothelial-dependent vasorelaxation and levels of serum nitrite. Various biochemical and histopathological estimations were also performed.

RESULTS

STZ treatment produced endothelial dysfunction, impairment of learning and memory, reduction in body weight and serum nitrite/nitrate, and increase in serum glucose, brain oxidative stress (increased brain thiobarbituric acid reactive species and decreased reduced glutathione levels), brain acetylcholinesterase activity and brain myeloperoxidase activity. Further a significant rise in brain tumor necrosis factor-α & interleukin-6 levels and brain neutrophil infiltration were also observed. Treatment of ozagrel (10 & 20 mg/kg, p. o.)/donepezil (0. 5 mg/kg, i.p., serving as standard) ameliorated STZ induced endothelial dysfunction; memory deficits; biochemical and histopathological changes.

CONCLUSIONS

It may be concluded that ozagrel markedly improved endothelial dysfunction; learning and memory; biochemical and histopathological alteration associated with STZ induced dementia and that TXA2 can be considered as an important therapeutic target for the management of VaD.

Glycated haemoglobin (HbA1c ), diabetes and neuropsychological performance in community-dwelling older adults

AIMS

Given that diabetes is associated with cognitive impairment and dementia in later life, we aimed to investigate the relationship between glycated haemoglobin (HbA_1c ), diabetes and domain-specific neuropsychological performance in older adults.

METHODS

Cross-sectional cohort study using data from the Trinity-Ulster-Department of Agriculture (TUDA) study. Participants underwent detailed cognitive and neuropsychological assessment using the Mini-Mental State Examination (MMSE), Frontal Assessment Battery (FAB) and Repeatable Assessment for Neuropsychological Status (RBANS). Linear regression was used to assess associations between HbA_1c , diabetes status and neuropsychological performance, with adjustment for important clinical covariates.

RESULTS

Of 4938 older adults (74.1 ± 8.3 years; 66.9% female), 16.3% (n = 803) had diabetes (HbA_1c  ≥ 6.5%; 48 mmol/mol), with prediabetes (HbA_1c  ≥ 5.7%-6.4%; 39-47 mmol/mol) present in 28.3% (n = 1395). Increasing HbA_1c concentration was associated with poorer overall performance on the FAB [β: -0.01 (-0.02, -0.00); p = 0.04 per % increase] and RBANS [β = -0.66 (-1.19, -0.13); p = 0.02 per % increase]. Increasing HbA_1c was also associated with poorer performance on immediate memory, visuo-spatial, language and attention RBANS domains. Diabetes was associated poorer performance on neuropsychological tests of immediate memory, language, visual-spatial and attention.

CONCLUSIONS

Both increasing HbA_1c and the presence of diabetes were associated with poorer cognitive and domain-specific performance in older adults. HbA_1c , and not just diabetes status per se, may represent an important target in the promotion of optimal brain health in older adults.

Potential new therapeutic target for Alzheimer's disease: Glucagon-like peptide-1

Increasing evidence shows a close relationship between Alzheimer's disease (AD) and type 2 diabetes mellitus (T2DM). Recently, glucagon-like peptide-1 (GLP-1), a gut incretin hormone, has become a well-established treatment for T2DM and is likely to be involved in treating cognitive impairment. In this mini review, the similarities between AD and T2DM are summarised with the main focus on GLP-1-based therapeutics in AD.

Neurocognitive dysfunction among type 2 diabetes patients attending primary health care in Jeddah, Saudi Arabia

CONTEXT

Identification of modifiable risk factors of neurocognitive dysfunction (NCDs) that would help in preventing neurocognitive dysfunction by means of appropriate measures.

OBJECTIVES

The study aims to provide an insight into the extent and cofactors ofNCDs among Saudi type II diabetes (T2DM) patients at the primary care level.

SETTINGS AND DESIGN

A cross-sectional study was conducted at five randomly selected primary health care centers (PHCCs) of Jeddah, Saudi Arabia.

SUBJECT AND METHODS

T2DM patients above 40 years, who were followed for T2DM diagnosed ≥ 1 year ago were recruited. The Arabic version of the Mini-Mental State Evaluation (MMSE) was used for screening NCDs, using education-adjusted cut-offs.

STATISTICAL ANALYSIS USED

Sociodemographic, diabetes-related, and other clinical and lifestyle factors were analyzed as cofactors of NCDs.

RESULTS

The study included 236 T2DM patients, who had mean ± SD age of 60.29 ± 9.45 years. The majority (61.0%) were female, and mean ± SD duration of T2DM was 14.1 ± 8.4 years (range = 1-45 years). The prevalence of NCDs was 35.2% (95% CI = 29.1%, 41.6%), and 5.1% of the participants had MMSE scores ≤ 10 indicating severe neurocognitive impairment. The congruence of significant sociodemographic factors delineated a high-risk profile, and multivariate regression analysis showed female gender, low educational level, longer duration of diabetes, geriatric age at T2DM diagnosis, inadequate glycemic control, and sedentary lifestyle as the independent risk factors for NCDs.

CONCLUSIONS

The population of middle-aged and older T2DM patients is highly exposed to NCDs, with the great contribution of other comorbidities and higher risk incurred by older, lowly educated females with long diabetes duration. Further improvements should be achieved to enhance the care offered to diabetic patients by improving glycemic control, screening for comorbidities, and early detection of neurocognitive decline.

The Janus-like Association between Proton Pump Inhibitors and Dementia

Early pharmacoepidemiological studies suggested that Proton Pump Inhibitors (PPIs) might increase the risk of Alzheimer’s Disease (AD) and non-AD related dementias. These findings were supported by preclinical studies, specifically stressing the proamyloidogenic and indirect anticholinergic effects of PPIs. However, further large-scale pharmacoepidemiological studies showed inconsistent results on the association between PPIs and dementia. Pharmacodynamically, these findings might be related to the LXR/RXR-mediated amyloid clearance effect and anti-inflammatory action of PPIs. Further aspects that influence PPI effects on AD are related to patient-specific pharmacokinetic and pharmacogenomic characteristics. In conclusion, a personalized (individualized) medicinal approach is necessary to model and predict the potential harmful or beneficial effects of PPIs in AD and non-AD-related dementias in the future.

Differential involvement of insulin receptor substrate (IRS)-1 and IRS-2 in brain insulin signaling is associated with the effects on amyloid pathology in a mouse model of Alzheimer's disease

Insulin signaling has been implicated in the metabolism as well as aging and longevity. Type 2 diabetes mellitus and its core pathology, insulin resistance, has also been implicated in the development of Alzheimer's disease (AD) and amyloid-β deposition in humans. By contrast, genetic ablation of the insulin/IGF-1 signaling (IIS) pathway components, e.g. insulin receptor substrate (IRS)-2, has been documented to suppress amyloid-β accumulation in the brains of transgenic mice overexpressing AD mutant β-amyloid precursor protein (APP). Therefore, the brain IIS may be a key modifiable molecular target in the pathophysiology of AD. IRS-1 and IRS-2 are critical nodes in IIS as substrates for insulin receptor and IGF-1 receptor, although the functional differences between IRS-1 and IRS-2 in the adult brain are yet to be explored. To examine their relative contribution to the brain IIS activity and AD pathomechanism, we generated APP transgenic mice lacking either IRS-1 or IRS-2. IRS-1 deficiency had little effects on the brain IIS pathway associated with compensatory activation of IRS-2, whereas IRS-2 deficiency was not fully compensated by activation of IRS-1, and the downstream activation of Akt also was significantly compromised. Pathological analyses of the cortical tissues showed that the biochemical levels of soluble and insoluble amyloid-β, the amyloid-β histopathology, and tau phosphorylation were not affected by the absence of IRS-1, in contrast to the marked alteration in IRS-2 deleted mice. These results suggest the predominance of IRS-2 in the brain IIS, and support the hypothesis that reduced IIS exerts anti-amyloid effects in the brain.

Corneal Nerve and Brain Imaging in Mild Cognitive Impairment and Dementia

Background:

Visual rating of medial temporal lobe atrophy (MTA) is an accepted structural neuroimaging marker of Alzheimer’s disease. Corneal confocal microscopy (CCM) is a non-invasive ophthalmic technique that detects neuronal loss in peripheral and central neurodegenerative disorders.

Objective:

To determine the diagnostic accuracy of CCM for mild cognitive impairment (MCI) and dementia compared to medial temporal lobe atrophy (MTA) rating on MRI.

Methods:

Subjects aged 60–85 with no cognitive impairment (NCI), MCI, and dementia based on the ICD-10 criteria were recruited. Subjects underwent cognitive screening, CCM, and MTA rating on MRI.

Results:

182 subjects with NCI (n = 36), MCI (n = 80), and dementia (n = 66), including AD (n = 19, 28.8%), VaD (n = 13, 19.7%), and mixed AD (n = 34, 51.5%) were studied. CCM showed a progressive reduction in corneal nerve fiber density (CNFD, fibers/mm²) (32.0±7.5 versus 24.5±9.6 and 20.8±9.3, p < 0.0001), branch density (CNBD, branches/mm²) (90.9±46.5 versus 59.3±35.7 and 53.9±38.7, p < 0.0001), and fiber length (CNFL, mm/mm²) (22.9±6.1 versus 17.2±6.5 and 15.8±7.4, p < 0.0001) in subjects with MCI and dementia compared to NCI. The area under the ROC curve (95% CI) for the diagnostic accuracy of CNFD, CNBD, CNFL compared to MTA-right and MTA-left for MCI was 78% (67–90%), 82% (72–92%), 86% (77–95%) versus 53% (36–69%) and 40% (25–55%), respectively, and for dementia it was 85% (76–94%), 84% (75–93%), 85% (76–94%) versus 86% (76–96%) and 82% (72–92%), respectively.

Conclusion:

The diagnostic accuracy of CCM, a non-invasive ophthalmic biomarker of neurodegeneration, was high and comparable with MTA rating for dementia but was superior to MTA rating for MCI.

Metformin a Potential Pharmacological Strategy in Late Onset Alzheimer's Disease Treatment

Alzheimer's disease (AD) is one of the most devastating brain disorders. Currently, there are no effective treatments to stop the disease progression and it is becoming a major public health concern. Several risk factors are involved in the progression of AD, modifying neuronal circuits and brain cognition, and eventually leading to neuronal death. Among them, obesity and type 2 diabetes mellitus (T2DM) have attracted increasing attention, since brain insulin resistance can contribute to neurodegeneration. Consequently, AD has been referred to "type 3 diabetes" and antidiabetic medications such as intranasal insulin, glitazones, metformin or liraglutide are being tested as possible alternatives. Metformin, a first line antihyperglycemic medication, is a 5'-adenosine monophosphate (AMP)-activated protein kinase (AMPK) activator hypothesized to act as a geroprotective agent. However, studies on its association with age-related cognitive decline have shown controversial results with positive and negative findings. In spite of this, metformin shows positive benefits such as anti-inflammatory effects, accelerated neurogenesis, strengthened memory, and prolonged life expectancy. Moreover, it has been recently demonstrated that metformin enhances synaptophysin, sirtuin-1, AMPK, and brain-derived neuronal factor (BDNF) immunoreactivity, which are essential markers of plasticity. The present review discusses the numerous studies which have explored (1) the neuropathological hallmarks of AD, (2) association of type 2 diabetes with AD, and (3) the potential therapeutic effects of metformin on AD and preclinical models.

Associations of the Glycaemic Control of Diabetes with Dementia and Physical Function in Rural-Dwelling Older Chinese Adults: A Population-Based Study

Purpose

To examine the associations of impaired fasting glucose (IFG) and glycaemic control of diabetes with dementia, global cognitive function and physical function among rural-dwelling Chinese older adults.

Patients and Methods

This population-based cross-sectional study included 4583 participants (age ≥65 years, 57.3% women) living in Yanlou Town, Yanggu County, western Shandong Province, China. In 2018, data were collected through interviews, clinical examinations, neuropsychological tests, and laboratory tests. Diabetes status was defined by self-reported physician-diagnosed diabetes, current use of antidiabetic agents, and fasting blood glucose tests. Global cognitive function was assessed using the Mini-Mental State Examination. Dementia was diagnosed following DSM-IV criteria, and Alzheimer's disease (AD) was diagnosed following the National Institute on Aging-Alzheimer's Association criteria. Physical function was assessed by the Short Physical Performance Battery. Data were analysed using multiple logistic and general linear regression models.

Results

IFG was found in 267 participants, and diabetes was diagnosed in 658 participants (257 with well-controlled diabetes, 401 with poorly controlled diabetes). Dementia was diagnosed in 166 participants (116 with AD), and physical functional impairment was found in 1973 participants. The multi-adjusted odds ratio (OR) of dementia associated with poorly controlled diabetes (vs without IFG or diabetes) was 2.41 (95% CI 1.52-3.84), and the OR of AD associated with poorly controlled diabetes was 2.32 (1.34-4.04). In addition, the adjusted OR of physical functional impairment was 1.40 (1.06-1.85) for well-controlled diabetes and 1.69 (1.35-2.12) for poorly controlled diabetes. However, IFG was not associated with cognitive or physical function.

Conclusion

The glycaemic control status of diabetes patients was associated with cognitive impairment and physical functional impairment.

The influence of childhood adversities on mid to late cognitive function: From the perspective of life course

Background

The effects of childhood adversities on cognitive function in later life are well reported. However, few studies have examined the cumulative mechanism, especially in Chinese population. This study aims to explore this cumulative effects of childhood adversities on mid to late cognitive decline in China.

Methods

Data were drawn from the second and third wave of the China Health and Retirement Longitudinal Study (CHARLS). We included 9,942 respondents aged 45 and above and retrospectively collected information on childhood adversities. Cognitive function was measured in three dimensions: orientation and calculation, immediate memory, and delayed memory. A structural equation model was employed for analysis.

Results

Age (β = -0.155, P<0.001) and mid to late depressive symptoms (β = -0.041, P<0.001) showed direct effects on cognitive decline. Low mid to late life socioeconomic status (SES) showed a direct effect on mid-late cognitive impairment (β = 0.603, P<0.001) and an indirect effect through depression (β = 0.007, P<0.001). Low childhood SES (β = 0.310, P<0.001), lack of friends (β = 0.208, P<0.001), parental mental health problems (β = 0.008, P<0.001), and poor relationship with parents (β = 0.001, P<0.001) had an indirect effect on cognitive impairment.

Conclusions

Childhood adversities had negative effects on cognitive function among middle aged and elderly population in China. The findings suggest that early counter measures on childhood adversities may lead to an effective reduction of cognitive impairment.

Concurrent cardiac transthyretin and brain β amyloid accumulation among the older adults: The Hisayama study

Previous studies have revealed risk for cognitive impairment in cardiovascular diseases. We investigated the relationship between degenerative changes of the brain and heart, with reference to Alzheimer's disease (AD) pathologies, cardiac transthyretin amyloid (ATTR) deposition, and cardiac fibrosis. A total of 240 consecutive autopsy cases of a Japanese population‐based study were examined. β amyloid (Aβ) of senile plaques, phosphorylated tau protein of neurofibrillary tangles, and ATTR in the hearts were immunohistochemically detected and graded according to the NIH‐AA guideline for AD pathology and as Tanskanen reported, respectively. Cerebral amyloid angiopathy (CAA) was graded according to the Vonsattel scale. Cardiac fibrosis was detected by picrosirius red staining, followed by image analysis. Cardiac ATTR deposition occurred after age 75 years and increased in an age‐dependent manner. ATTR deposition was more common, and of higher grades, in the dementia cases. We subdivided the cases into two age groups: ≤90 years old (n = 173) and >90 years old (n = 67), which was the mean and median age at death of the AD cases. When adjusted for age and sex, TTR deposition grades correlated with Aβ phase score (A2–3), the Consortium to Establish a Registry for AD score (sparse to frequent), and high Braak stage (V–VI) only in those aged ≤90 years at death. No significant correlation was observed between the cardiac ATTR deposition and CAA stages, or between cardiac fibrosis and AD pathologies. Collectively, AD brain pathology correlated with cardiac TTR deposition among the older adults ≤90 years.

Association Between the Prognostic Nutritional Index and Cognitive Function Among Older Adults in the United States: A Population-Based Study

BACKGROUND

Nutritional status has been recognized as an important factor influencing cognitive function-related diseases, but few comprehensive nutrition indicators are available to assess the risk of cognitive decline.

OBJECTIVE

This study aimed to investigate the relationship between the prognostic nutritional index (PNI) and cognitive function in an elderly population, and the differences in nutrient intake between different levels of nutritional risk.

METHODS

Based on cross-sectional data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014, we included 2,564 older participants. The lower quartile of each of the four cognitive tests was considered to have cognitive function impairment (CFI). Binary and multivariate logistic regression models were used to estimate the relationship between the PNI and the odds ratio of CFI.

RESULTS

After adjustment for confounding variables, we found that the odds of CFI were significantly lower for participants with normal PNI levels than for those with low PNI levels. In a comparison of global cognitive impairment scores, participants with a normal PNI had lower ratios of poor cognitive performance than those with a low PNI. By comparing the nutrient intake at different PNI levels, we found a reduction in the intake of protein, dietary fiber, total saturated fatty acids, and multiple micronutrients in the low PNI group.

CONCLUSION

Our study shows that the PNI can be a good predictor of the odds of CFI in the elderly population and that it is a convenient indicator of reduced intake of nutrients which may be important to brain health.

Elevated Plasma Free Fatty Acid Susceptible to Early Cognitive Impairment in Type 2 Diabetes Mellitus

BACKGROUND

Elevated free fatty acid (FFA) induces lipotoxicity, attributed to diabetes and cognitive decline. Sterol regulatory element-binding protein-1c (SREBP-1c) regulates lipid metabolism.

OBJECTIVE

We investigated the roles of FFA in mild cognitive impairment (MCI) of type 2 diabetes mellitus (T2DM) patients and determine its association with rs11868035 polymorphism.

METHODS

We recruited 191 Chinese T2DM patients into two groups through Montreal Cognitive Assessment. Demographic and clinical data were collected, multiple domain cognitive functions were tested, plasma FFA levels were measured through ELISA, and SREBP-1c rs11868035 genotype was detected using the Seqnome method.

RESULTS

In comparison with the healthy-cognition group (n = 128), the MCI group (n = 63) displayed lower glucose control (p = 0.012) and higher plasma FFA level (p = 0.021), which were independent risk factors of MCI in T2DM patients in multivariate regression analysis (OR = 1.270, p = 0.003; OR = 1.005, p = 0.036). Additionally, the plasma FFA levels of MCI patients were positively correlated with Stroop color word test-C time scores (r = 0.303, p = 0.021) and negatively related to apolipoprotein A1 levels (r = -0.311, p = 0.017), which are associated positively with verbal fluency test scores (r = 0.281, p = 0.033). Both scores reflected attention ability and executive function. Moreover, the G allele carriers of rs11868035 showed higher digit span test scores than non-carriers in T2DM patients (p = 0.019) but without correlation with plasma FFA levels.

CONCLUSION

In T2DM, elevated plasma level of FFA, when combined with lower apolipoprotein A1 level portends abnormal cholesterol transport, were susceptible to early cognitive impairment, especially for attention and execution deficits. The G allele of SREBP-1c rs11868035 may be a protective factor for memory.

Three-dimensional remodeling of functional cerebrovascular architecture and gliovascular unit in leptin receptor-deficient mice

The cerebrovascular sequelae of diabetes render victims more susceptible to ischemic stroke, vascular cognitive impairment, and Alzheimer's disease. However, limited knowledge exists on the progressive changes in cerebrovascular structure and functional remodeling in type 2 diabetes. To ascertain the impact of diabetes on whole-brain cerebrovascular perfusion, leptin-receptor-deficient mice were transcardially injected with tomato-lectin before sacrifice. The whole brain was clarified by the Fast free-of-acrylamide clearing tissue technique. Functional vascular anatomy of the cerebrum was visualized by light-sheet microscopy, followed by analysis in Imaris software. We observed enhanced neovascularization in adult db/db mice, characterized by increased branch level and loop structures. Microvascular hypoperfusion was initially detected in juvenile db/db mice, suggesting early onset of insufficient microcirculation. Furthermore, gliovascular unit remodeling was verified by loss of pericytes and overactivation of microglia and astrocytes in adult diabetic mice. However, the integrity of the blood-brain barrier (BBB) was fundamentally preserved, as shown by a lack of extravasation of IgG into the brain parenchyma. In summary, we, for the first time, reveal that functional cerebrovascular remodeling occurs as early as four weeks in db/db mice and the deficit in gliovascular coupling may play a role in cerebral hypoperfusion before BBB breakdown in 16-week-old db/db mice.

Glycemic Control, Diabetic Complications, and Risk of Dementia in Patients With Diabetes: Results From a Large U.K. Cohort Study

OBJECTIVE

Type 2 diabetes is an established risk factor for dementia. However, the roles of glycemic control and diabetic complications in the development of dementia have been less well substantiated. This large-scale cohort study aims to examine associations of longitudinal HbA_1c levels and diabetic complications with the risk of dementia incidence among patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Data of eligible patients with diabetes, aged ≥50 years in the U.K. Clinical Practice Research Datalink from 1987 to 2018, were analyzed. Time-varying Cox regressions were used to estimate adjusted hazard ratios (HRs) and 95% CIs for dementia risk.

RESULTS

Among 457,902 patients with diabetes, 28,627 (6.3%) incident dementia cases were observed during a median of 6 years' follow-up. Patients with recorded hypoglycemic events or microvascular complications were at higher risk of dementia incidence compared with those without such complications (HR 1.30 [95% CI 1.22-1.39] and 1.10 [1.06-1.14], respectively). The HbA_1c level, modeled as a time-varying exposure, was associated with increased dementia risk (HR 1.08 [95% CI 1.07-1.09] per 1% HbA_1c increment) among 372,287 patients with diabetes with postdiagnosis HbA_1c records. Similarly, a higher coefficient of variation of HbA_1c during the initial 3 years of follow-up was associated with higher subsequent dementia risk (HR 1.03 [95% CI 1.01-1.04] per 1-SD increment).

CONCLUSIONS

Higher or unstable HbA_1c levels and the presence of diabetic complications in patients with type 2 diabetes are associated with increased dementia risk. Effective management of glycemia might have a significant role in maintaining cognitive health among older adults with diabetes.

Microvascular basis of cognitive impairment in type 1 diabetes

The complex computations of the brain require a constant supply of blood flow to meet its immense metabolic needs. Perturbations in blood supply, even in the smallest vascular networks, can have a profound effect on neuronal function and cognition. Type 1 diabetes is a prevalent and insidious metabolic disorder that progressively and heterogeneously disrupts vascular signalling and function in the brain. As a result, it is associated with an array of adverse vascular changes such as impaired regulation of vascular tone, pathological neovascularization and vasoregression, capillary plugging and blood brain barrier disruption. In this review, we highlight the link between microvascular dysfunction and cognitive impairment that is commonly associated with type 1 diabetes, with the aim of synthesizing current knowledge in this field.

The Impact of Obesity on Microglial Function: Immune, Metabolic and Endocrine Perspectives

Increased life expectancy in combination with modern life style and high prevalence of obesity are important risk factors for development of neurodegenerative diseases. Neuroinflammation is a feature of neurodegenerative diseases, and microglia, the innate immune cells of the brain, are central players in it. The present review discusses the effects of obesity, chronic peripheral inflammation and obesity-associated metabolic and endocrine perturbations, including insulin resistance, dyslipidemia and increased glucocorticoid levels, on microglial function.

Alzheimer’s disease and type 2 diabetes mellitus: Pathophysiologic and pharmacotherapeutics links

At present, Alzheimer’s disease (AD) and type 2 diabetes mellitus (T2DM) are two highly prevalent disorders worldwide, especially among elderly individuals. T2DM appears to be associated with cognitive dysfunction, with a higher risk of developing neurocognitive disorders, including AD. These diseases have been observed to share various pathophysiological mechanisms, including alterations in insulin signaling, defects in glucose transporters (GLUTs), and mitochondrial dysfunctions in the brain. Therefore, the aim of this review is to summarize the current knowledge regarding the molecular mechanisms implicated in the association of these pathologies as well as recent therapeutic alternatives. In this context, the hyperphosphorylation of tau and the formation of neurofibrillary tangles have been associated with the dysfunction of the phosphatidylinositol 3-kinase and mitogen-activated protein kinase pathways in the nervous tissues as well as the decrease in the expression of GLUT-1 and GLUT-3 in the different areas of the brain, increase in reactive oxygen species, and production of mitochondrial alterations that occur in T2DM. These findings have contributed to the implementation of overlapping pharmacological interventions based on the use of insulin and antidiabetic drugs, or, more recently, azeliragon, amylin, among others, which have shown possible beneficial effects in diabetic patients diagnosed with AD.

Effect of Garcinia mangostana pericarp extract on glial NF-κB levels and expression of serum inflammation markers in an obese-type 2 diabetes mellitus animal model

Type 2 diabetes mellitus (T2DM) is an age-related disease associated with cerebral inflammation and Alzheimer's disease. Garcinia mangostana pericarp (GMP) possesses antihyperglycemic, antidiabetic and anti-inflammatory effects. The aim of the present study was to evaluate the effect of GMP extract on cerebral inflammation in Wistar rats with T2DM by examining the expression levels of glial nuclear factor-κB (NF-κB), interleukin (IL)-6, tumor necrosis factor-α (TNF-α) and superoxide dismutase (SOD). A total of 36 8-10-week-old male Wistar rats were randomly divided into six groups and provided a standard diet (normal control; C1), high-fat diet (HFD) with 200 g/kg GMP extract BW/day (GMP control; C2), HFD with streptozotocin-nicotinamide (diabetic control; C3), and HFD with 100 (M1), 200 (M2) or 400 g/kg body weight (BW)/day (M3) GMP extract for Wistar rats with diabetes. GMP extract was administered for 8 weeks after induction of T2DM was confirmed. Glial NF-κB activity was assessed by immunohistochemical staining, and by measuring IL-6 levels, TNF-α levels and SOD activity in the serum using ELISA. BW significantly increased following HFD treatment. After 7 weeks, the BW remained significantly higher compared with the normal control and GMP extract-treated groups, but decreased continuously in the T2DM groups. Glial NF-κB immunoreaction in the hippocampal region was significantly higher in the diabetic Wistar rats compared with the normal control Wistar rats, and 200 g/kg BW/day GMP significantly reduced its activity. The T2DM Wistar rats showed significantly higher expression levels of serum IL-6 and TNF-α and lower activity of SOD compared with the normal control Wistar rats. Meanwhile, rats in GMP groups M1, M2 and M3 exhibited significant reductions in the levels of IL-6 and TNF-α expression, and increases in SOD activity. GMP extract treatment effectively reduced hippocampal NF-κB, IL-6 and TNF-α levels and increased antioxidant SOD activity. These results suggest that GMP extract prevents cerebral inflammation in T2DM Wistar rats.

The Association Between Second-Line Oral Antihyperglycemic Medication on Types of Dementia in Type 2 Diabetes: A Nationwide Real-World Longitudinal Study

BACKGROUND

There are few reports that evaluated the association between various types of dementia and dual oral therapy with antihyperglycemic medication.

OBJECTIVE

The goal of this study was to investigate the association between treatment of dual antihyperglycemic medication and dementia subclass in type 2 diabetes mellitus using the Korean National Health Insurance System.

METHODS

This study included 701,193 individuals with diabetes prescribed dual oral therapy between 2009 and 2012 from the Korean National Health Insurance Service Database, which were tracked until 2017. All-cause, Alzheimer's (AD) and vascular dementia (VaD) were investigated by dual oral therapy. Adjustments were made for age, sex, income, diabetes duration, hypertension, dyslipidemia, smoking, drinking, exercise, body mass index, glucose level, and estimated glomerular filtration rate.

RESULTS

Dual therapy with metformin (Met) + dipeptidyl peptidase-4 inhibitor (DPP-4i), Met + thiazolidinedione (TZD), and sulfonylurea (SU) + thiazolidinediones (TZD) were significantly associated with all-cause dementia (HR = 0.904, 0.804, and 0.962, respectively) and VaD (HR = 0.865, 0.725, and 0.911, respectively), compared with Met + SU. Met + DPP-4i and Met + TZD were associated with significantly lower risk of AD (HR = 0.922 and 0.812), compared with Met + SU. Dual therapy with TZD was associated with a significantly lower risk of all-cause dementia, AD, and VaD than nonusers of TZD (HR = 0.918, 0.925 and 0.859, respectively).

CONCLUSION

Adding TZD or DPP-4i instead of SU as second-line anti-diabetic treatment may be considered for delaying or preventing dementia. Also, TZD users relative to TZD non-users on dual oral therapy were significantly associated with lower risk of various types of dementia.

Cognitive performance in midlife type 2 diabetes: results from the ENBIND study

AIMS

To establish the impact of uncomplicated type 2 diabetes on cognitive and neuropsychological performance in midlife.

METHODS

We performed a cross-sectional study of middle-aged adults with uncomplicated type 2 diabetes and a cohort of healthy control participants. General cognition was assessed using the Montreal Cognitive Assessment test and neuropsychological assessment was undertaken using a detailed neuropsychological assessment battery.

RESULTS

A total of 152 participants (102 with type 2 diabetes and 50 controls) were recruited (mean age 52 ± 8 years, 51% women). Participants with midlife type 2 diabetes were more than twice as likely to make an error on the Montreal Cognitive Assessment test [incidence rate ratio 2.44 (95% CI 1.54 to 3.87); P < 0.001]. Further, type 2 diabetes was also associated with significantly lower memory composite score [β: -0.20 (95% CI -0.39 to -0.01); P = 0.04] and paired associates learning score [β: = -1.97 (95% CI -3.51, -0.43); P = 0.01] on the neuropsychological assessment battery following adjustment for age, sex, BMI, educational attainment and hypercholesterolaemia.

CONCLUSIONS

Even in midlife, type 2 diabetes was associated with small but statistically significant cognitive decrements. These statistically significant decrements, whilst not clinically significant in terms of objective cognitive impairment, may have important implications in selecting out individuals most at risk of later cognitive decline for potential preventative interventions in midlife.

The association between triglyceride glucose index and depression: data from NHANES 2005-2018

BACKGROUND

The association between triglyceride glucose (TyG) index and depression is unclear. We conducted this analysis to explore whether higher TyG index is associated with a higher odd of depression.

METHODS

This was an observational study using data from the National Health and Nutrition Examination Survey (2005-2018), a cross-sectional and nationally representative database. Depression was assessed using the Patient Health Questionnaire-9 (PHQ-9). TyG index was calculated based on the equation as follows: ln [triglyceride (mg/dL) × fasting blood glucose (mg/dL)/2], and participants were divided into quartiles based on TyG index. Weighted multivariable logistic regression models were used to explore the relationship between the TyG index and depression.

RESULTS

A total of 13,350 patients were included, involving 1001 (7.50%) individuals with depression. Higher TyG index is significantly associated with elevated depressive symptoms in U.S. adults. Multivariate-adjusted HRs for patients in the TyG index 4th quartile were higher for depression (OR = 1.46; 95% confidence interval (CI) 1.30, 1.64) compared with the 1st quartile of TyG index. Similar results were seen in men and women, across age groups, and baseline comorbidities.

CONCLUSION

In this large cross-sectional study, our result suggests that population with higher TyG index are significantly more likely to have depressive symptoms in U.S. adults.

Risk factors for hyperglycemia and hypoglycemia in adults with pharmacologically treated type 2 diabetes mellitus: a quantitative systematic review protocol

OBJECTIVE

The objective of this review is to identify and synthesize the risk factors for hyperglycemia or hypoglycemia in adults with pharmacologically treated type 2 diabetes mellitus in any scenarios and environments for health care.

INTRODUCTION

Studies around the world have investigated which factors are associated with episodes of alteration of blood glucose level. It is through the characterization of these factors that nurses can plan and intervene accurately in the control of serum glucose levels in people with diabetes.

INCLUSION CRITERIA

This review will include studies conducted among adults with pharmacologically treated type 2 diabetes mellitus in any scenarios and environments for health care. Studies should focus on risk factors for the variation of fasting glycemic levels lower than 3.9 mmol/L and higher than 7.21 mmol/L, as well as postprandial glycemic levels lower than 3.9 mmol/L and higher than 10 mmol/L.

METHODS

Databases to be searched include MEDLINE, Embase, CINAHL, PsycINFO, Web of Science, Scopus, LILACS, and ScienceDirect. Following the search, titles and abstracts will be screened by two independent reviewers for assessment against the inclusion criteria for the review. The full text of selected citations will be assessed in detail against the inclusion criteria, and studies selected for retrieval will be assessed by two independent reviewers for methodological validity using JBI critical appraisal tools. Studies will not be excluded based on their quality assessment. Data will be extracted using the standardized data extraction tools. Quantitative data will, where possible, be pooled in statistical meta-analysis.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO (CRD42019134755).

Insulin Resistance and Diabetes Mellitus in Alzheimer's Disease

Type 2 diabetes mellitus is a progressive disease that is characterized by the appearance of insulin resistance. The term insulin resistance is very wide and could affect different proteins involved in insulin signaling, as well as other mechanisms. In this review, we have analyzed the main molecular mechanisms that could be involved in the connection between type 2 diabetes and neurodegeneration, in general, and more specifically with the appearance of Alzheimer's disease. We have studied, in more detail, the different processes involved, such as inflammation, endoplasmic reticulum stress, autophagy, and mitochondrial dysfunction.

Increased Plasma Level of 24S-Hydroxycholesterol and Polymorphism of CYP46A1 SNP (rs754203) Are Associated With Mild Cognitive Impairment in Patients With Type 2 Diabetes

Background

Abnormal cholesterol metabolism is common in type 2 diabetes mellitus (T2DM) and causes dementia. Cholesterol 24S-hydroxylase (CYP46A1) converts cholesterol into 24S-hydroxycholesterol (24-OHC) and maintains cholesterol homeostasis in the brain.

Objective

This study aimed to investigate the roles of 24-OHC and the CYP46A1 (rs754203) polymorphism in patients with T2DM and mild cognitive impairment (MCI).

Methods

A total of 193 Chinese patients with T2DM were recruited into two groups according to the Montreal Cognitive Assessment (MoCA). Demographic and clinical data were collected, and neuropsychological tests were conducted. Enzyme-linked immunosorbent assay (ELISA) and Seqnome method were used to detect the concentration of plasma 24-OHC and the CYP46A1 rs754203 genotype, respectively.

Results

Compared with 118 healthy cognition participants, patients with MCI (n = 75) displayed a higher plasma level of 24-OHC and total cholesterol concentration (all p = 0.031), while no correlation was found between them. In the overall diabetes population, the plasma level of 24-OHC was negatively correlated with MoCA (r = −0.150, p = 0.039), and it was further proved to be an independent risk factor of diabetic MCI (OR = 1.848, p = 0.001). Additionally, patients with MCI and the CC genotype of CYP46A1 rs754203 showed the highest plasma level of 24-OHC even though the difference was not statistically significant, and they obtained low scores in both the verbal fluency test and Stroop color and word test A (p = 0.008 and p = 0.029, respectively).

Conclusion

In patients with T2DM, high plasma level of 24-OHC and the CC genotype carrier of CYP46A1 rs754203 may portend a high risk of developing early cognitive impairment, including attention and executive deficits.

Non-Coding RNAs Based Molecular Links in Type 2 Diabetes, Ischemic Stroke, and Vascular Dementia

This article reviews recent advances in the study of microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and their functions in type 2 diabetes mellitus (T2DM), ischemic stroke (IS), and vascular dementia (VaD). miRNAs and lncRNAs are gene regulation markers that both regulate translational aspects of a wide range of proteins and biological processes in healthy and disease states. Recent studies from our laboratory and others have revealed that miRNAs and lncRNAs expressed differently are potential therapeutic targets for neurological diseases, especially T2DM, IS, VaD, and Alzheimer's disease (AD). Currently, the effect of aging in T2DM, IS, and VaD and the cellular and molecular pathways are largely unknown. In this article, we highlight results from the works on the molecular connections between T2DM and IS, and IS and VaD. In each disease, we also summarize the pathophysiology and the differential expressions of miRNAs and lncRNAs. Based on current research findings, we hypothesize that 1) T2DM bi-directionally and age-dependently induces IS and VaD, and 2) these changes are precursors to the onset of dementia in elderly people. Research into these hypotheses is required to examine further whether research efforts on reducing T2DM, IS, and VaD may affect dementia and/or delay the AD disease process in the aged population.

Prevalence and Incidence of Dementia in People with Diabetes Mellitus

BACKGROUND

Few studies have shown that an increased risk of dementia is associated with diabetes mellitus.

OBJECTIVE

To estimate the prevalence and incidence of dementia in people with diabetes in primary care in the UK.

METHODS

We conducted a descriptive study using the UK The Health Improvement Network (THIN) database. People diagnosed with diabetes from 2000 to 2016 were included in the study. Prevalence and incidence rates of dementia were calculated annually, stratified by age and gender.

RESULTS

The prevalence of dementia was 0.424% [95% CI (0.420%-0.427%)] in 2000 and 2.508% [95% CI (2.501%-2.515%)] in 2016. The highest prevalence was in those aged 85+ from 2.9% [95% CI (2.890%-2.974%)] in 2000 to 11.3% [95% CI (11.285%-11.384%)] in 2016. The incidence of dementia increased 3.7 times, from 0.181 cases per 100 persons [95% CI (0.179-0.183)] in 2000 to 0.683 cases per 100 persons [95% CI (0.679-0.686)] in 2016, respectively. Women had a higher prevalence and incidence of dementia than men 3.138% [95% CI (3.127%-3.150%)] versus 2.014% [95% CI (2.006%-2.022%)] and 0.820 [95% CI (0.814-0.826)] versus 0.576 cases per 100 persons [95% CI (0.571-0.580)] in 2016, respectively.

CONCLUSION

There was a trend of increasing prevalence and incidence of dementia in people with diabetes over the period of 2000 to 2016. This study adds to the evidence on dementia prevalence and incidence, particularly in the diabetic population.

Factors Associated with Mortality Including Nursing Home Transitions: A Retrospective Analysis of 25,418 People Prescribed Anti-Dementia Drugs in Northern Ireland

BACKGROUND

Understanding factors associated with mortality after a dementia diagnosis can provide essential information to the person with dementia, their family, and caregivers. To date very little is known about the factors associated with mortality after a dementia diagnosis in Northern Ireland.

OBJECTIVE

To determine how demographic and other factors such as deprivation and comorbidity medications influence mortality rates after a dementia diagnosis in Northern Ireland and whether these factors are influenced through nursing home transitions.

METHODS

25,418 people prescribed anti-dementia medication were identified through the enhanced prescribing database between 2010 and 2016. The impact of covariates including age, gender, marital status, deprivation measure, urban/rural classification, and comorbidity medications were examined using cox proportional hazard models with hazard ratios (HR) and 95% confidence intervals.

RESULTS

Between 2010 and 2016, 12,129 deaths occurred, with 114 deaths/1,000 person years. Males had significantly higher mortality rates in comparison to females (HR = 1.28; 95% CI = 1.23-1.33); this was true regardless of whether the person with dementia transitioned to a nursing home. People prescribed anti-dementia drugs living with lower levels of deprivation had significantly lower mortality rates in comparison to people living with the highest levels of deprivation (HR = 0.93; 95% CI = 0.89-0.97). Diabetic (HR = 1.18; 95% CI = 1.07-1.29) and anti-arrhythmic (HR = 2.44; 95% CI = 1.01-5.91) medication in particular significantly influenced mortality.

CONCLUSION

Male gender, higher comorbidity medications, and living in areas of higher deprivation significantly increased mortality rates for people prescribed anti-dementia drugs in our study population. When comorbidity medications were classified, only anti-arrhythmia and diabetic medications significantly increased mortality. Future research should continue to investigate factors which influence mortality after a dementia diagnosis.

High Plasma Resistin Levels Portend the Insulin Resistance-Associated Susceptibility to Early Cognitive Decline in Patients with Type 2 Diabetes Mellitus

BACKGROUND

Metabolic disorders, including insulin resistance, obesity, and hyperlipidemia occur frequently prior to hyperglycemia in patients with type 2 diabetes mellitus (T2DM) and cause mild cognitive impairment (MCI).

OBJECTIVE

We investigated the involvement of resistin in these metabolic abnormalities contributes to MCI in patients with T2DM.

METHODS

A total of 138 hospitalized patients with T2DM were enrolled and categorized into MCI and non-MCI groups according to the Montreal Cognitive Assessment (MoCA) score. Metabolic indicators and cognitive state were assessed, and plasma resistin levels were determined by ELISA.

RESULTS

The resistin levels and homeostasis model assessment of insulin resistance (HOMA-IR) scores of MCI and gender-stratified subgroups were significantly higher than those of controls without MCI (all p < 0.01). Correlation analysis showed that the resistin level was negatively associated with majority of cognitive domains, e.g., MoCA (r = -0.693, p < 0.001) and Mini-Mental State Examination (r = -0.571, p < 0.001), and was related to HOMA-IR (r = 0.667, p < 0.001) but not to obesity and lipid indices. Multivariable regression analysis indicated that resistin (β= -0.675, p < 0.001) and educational level (β= 0.177, p = 0.003) were independent risk factors of MoCA in patients with T2DM.

CONCLUSIONS

High plasma resistin levels portend the insulin resistance-related susceptibility to early cognitive decline in Chinese patients with T2DM. The involvement of this adipokine in other metabolic disorders leading to diabetic MCI and its clinical value for early disease screening must be further studied.

Insulin Signaling as a Therapeutic Target in Glaucomatous Neurodegeneration

Glaucoma is a multifactorial disease that is conventionally managed with treatments to lower intraocular pressure (IOP). Despite these efforts, many patients continue to lose their vision. The degeneration of retinal ganglion cells (RGCs) and their axons in the optic tract that characterizes glaucoma is similar to neurodegeneration in other age-related disorders of the central nervous system (CNS). Identifying the different molecular signaling pathways that contribute to early neuronal dysfunction can be utilized for neuroprotective strategies that prevent degeneration. The discovery of insulin and its receptor in the CNS and retina led to exploration of the role of insulin signaling in the CNS. Historically, insulin was considered a peripherally secreted hormone that regulated glucose homeostasis, with no obvious roles in the CNS. However, a growing number of pre-clinical and clinical studies have demonstrated the potential of modulating insulin signaling in the treatment of neurodegenerative diseases. This review will highlight the role that insulin signaling plays in RGC neurodegeneration. We will focus on how this pathway can be therapeutically targeted to promote RGC axon survival and preserve vision.

Ozagrel a thromboxane A2 synthase inhibitor extenuates endothelial dysfunction, oxidative stress and neuroinflammation in rat model of bilateral common carotid artery occlusion induced vascular dementia

The present study investigates the potential of ozagrel, a thromboxane A2 (TXA2) synthase inhibitor, in bilateral common carotid artery occlusion (BCCAo) induced vascular dementia (VaD). Wistar rats were subjected to BCCAo procedure under anesthesia to induce VaD. Morris water maze (MWM) test was employed on 7th day post-surgery to determine learning and memory. Endothelial dysfunction was assessed in isolated aorta by observing endothelial dependent vasorelaxation and levels of serum nitrite. A battery of biochemical and histopathological estimations was performed. Expression analysis of inflammatory cytokines TNF-α and IL-6 was carried out by RT-PCR. BCCAo produced significant impairment in endothelium dependent vasorelaxation and decrease in serum nitrite levels indicating endothelial dysfunction along with poor performance on MWM represents impairment of learning and memory. There was a significant rise in brain oxidative stress level (indicated by increase in brain thiobarbituric acid reactive species and decrease in reduced glutathione levels); increase in brain acetylcholinesterase activity; brain myeloperoxidase activity; brain TNF-α & IL-6 levels, brain TNF-α & IL-6 mRNA expression and brain neutrophil infiltration (as marker of inflammation) were also observed. Treatment of ozagrel (10 & 20 mg/kg, p. o.)/donepezil (0. 5 mg/kg, i.p., serving as standard) ameliorated BCCAo induced endothelial dysfunction; memory deficits; biochemical and histopathological changes in a significant manner. It may be concluded that ozagrel markedly improved endothelial dysfunction; learning and memory; biochemical and histopathological alteration associated with BCCAo induced VaD and that TXA2 can be considered as an important therapeutic target for the treatment of VaD.

Brain insulin, insulin-like growth factor 1 and glucagon-like peptide 1 signalling in Alzheimer's disease

Although the brain was once considered an insulin-independent organ, insulin signalling is now recognised as being central to neuronal health and to the function of synapses and brain circuits. Defective brain insulin signalling, as well as related signalling by insulin-like growth factor 1 (IGF-1), is associated with neurological disorders, including Alzheimer's disease, suggesting that cognitive impairment could be related to a state of brain insulin resistance. Here, I briefly review key epidemiological/clinical evidence of the association between diabetes, cognitive decline and AD, as well as findings of reduced components of insulin signalling in AD brains, which led to the initial suggestion that AD could be a type of brain diabetes. Particular attention is given to recent studies illuminating mechanisms leading to neuronal insulin resistance as a key driver of cognitive impairment in AD. Evidence of impaired IGF-1 signalling in AD is also examined. Finally, we discuss potentials and possible limitations of recent and on-going therapeutic approaches based on our increased understanding of the roles of brain signalling by insulin, IGF-1 and glucagon-like peptide 1 in AD.

Amyloid-related protein changes associated with dementia differ according to severity of hypoglycemia

INTRODUCTION

Hypoglycemia in type 2 diabetes (T2D) may increase risk for Alzheimer's disease (AD), but no data on changes in AD-related proteins with differing degrees of hypoglycemia exist. We hypothesized that milder prolonged hypoglycemia would cause greater AD-related protein changes versus severe transient hypoglycemia.

RESEARCH DESIGN AND METHODS

Two prospective case-control induced hypoglycemia studies were compared: study 1, hypoglycemic clamp to 2.8 mmol/L (50 mg/dL) for 1 hour in 17 subjects (T2D (n=10), controls (n=7)); study 2, hypoglycemic clamp to 2.0 mmol/L (36 mg/dL) undertaken transiently and reversed in 46 subjects (T2D (n=23), controls (n=23)). Blood sampling at baseline, hypoglycemia and 24-hour post-hypoglycemia, with proteomic analysis of amyloid-related proteins performed.

RESULTS

In control subjects, the percentage change from baseline to hypoglycemia differed between study 1 and study 2 for 5 of 11 proteins in the AD-related panel: serum amyloid A1 (SAA1) (p=0.009), pappalysin (PAPPA) (p=0.002), apolipoprotein E2 (p=0.02), apolipoprotein E3 (p=0.03) and apolipoprotein E4 (p=0.02). In controls, the percentage change from baseline to 24 hours differed between studies for two proteins: SAA1 (p=0.003) and PAPPA (p=0.004); however, after Bonferroni correction only SAA1 and PAPPA remain significant. In T2D, there were no differential protein changes between the studies.

CONCLUSIONS

The differential changes in AD-related proteins were seen only in control subjects in response to iatrogenic induction of hypoglycemic insults of differing length and severity and may reflect a protective response that was absent in subjects with T2D. Milder prolonged hypoglycemia caused greater AD-related protein changes than severe acute hypoglycemia in control subjects.

TRIAL REGISTRATION NUMBERS

NCT02205996, NCT03102801.

Diabetes and Prediabetes Inhibit Reversion from Mild Cognitive Impairment to Normal Cognition

OBJECTIVES

Diabetes and prediabetes contribute to an increased risk of cognitive decline and dementia. Currently, it remains unclear whether elevated blood HbA1c levels, including prediabetes levels, affect reversion from mild cognitive impairment (MCI) to normal cognition. This study, therefore, aimed to examine the prospective associations of diabetes and prediabetes with reversion from MCI to normal cognition among community-dwelling older adults.

DESIGN

Longitudinal cohort study with a 4-year follow-up.

SETTING AND PARTICIPANTS

Community-dwelling older adults with MCI, aged ≥65 years at baseline (n = 787).

METHODS

Participants' medical history of diabetes and blood HbA1c levels at baseline were assessed, and they were classified as control, prediabetes, and diabetes. Objective cognitive screening was performed using a multicomponent neurocognitive test at baseline and follow-up. Reversion from MCI to normal cognition over 4 years was determined. In the longitudinal analysis, we performed multiple imputations to adjust for a selection bias and loss of information.

RESULTS

The reversion rates of MCI in the control, prediabetes, and diabetes groups were 63.4%, 55.6%, and 42.9%, respectively, in the completed follow-up dataset, and 54.6%, 47.2%, and 34.1%, respectively, in the imputed dataset. Multivariate logistic regression showed that diabetes decreases the probability of MCI reversion both before and after multiple imputations [odds ratio (OR) 0.37; 95% confidence interval (CI) 0.18-0.74 for before imputation, OR 0.37; 95% CI 0.19-0.72 for after imputation]. Furthermore, prediabetes also showed significantly decreased probabilities of MCI reversion both before and after multiple imputations (OR 0.57; 95% CI 0.34-0.94 for before imputation, OR 0.60; 95% CI 0.37-0.97 for after imputation).

CONCLUSIONS AND IMPLICATIONS

Diabetes and prediabetes could inhibit MCI reversion. Adequate glycemic control may be effective in enhancing the reversion from MCI to normal cognition in a community setting.

SSAO/VAP-1 in Cerebrovascular Disorders: A Potential Therapeutic Target for Stroke and Alzheimer's Disease

The semicarbazide-sensitive amine oxidase (SSAO), also known as vascular adhesion protein-1 (VAP-1) or primary amine oxidase (PrAO), is a deaminating enzyme highly expressed in vessels that generates harmful products as a result of its enzymatic activity. As a multifunctional enzyme, it is also involved in inflammation through its ability to bind and promote the transmigration of circulating leukocytes into inflamed tissues. Inflammation is present in different systemic and cerebral diseases, including stroke and Alzheimer’s disease (AD). These pathologies show important affectations on cerebral vessels, together with increased SSAO levels. This review summarizes the main roles of SSAO/VAP-1 in human physiology and pathophysiology and discusses the mechanisms by which it can affect the onset and progression of both stroke and AD. As there is an evident interrelationship between stroke and AD, basically through the vascular system dysfunction, the possibility that SSAO/VAP-1 could be involved in the transition between these two pathologies is suggested. Hence, its inhibition is proposed to be an interesting therapeutical approach to the brain damage induced in these both cerebral pathologies.

Type 2 Diabetes and Cognitive Status in the Health and Retirement Study: A Mendelian Randomization Approach

Background

Type 2 diabetes mellitus (T2DM) and dementia are leading causes of mortality and disability in the US. T2DM has been associated with dementia; however, causality has not been clearly established. This study tested inferred causality between T2DM and dementia status using a Mendelian randomization approach.

Methods

Participants (50+ years) from the 2010 wave of the Health and Retirement Study of European or African genetic ancestry were included (n = 10,322). History of T2DM was self-reported. Cognitive status (dementia, cognitive impairment non-dementia, or normal cognition) was defined from clinically validated cognitive assessments. Cumulative genetic risk for T2DM was determined using a polygenic score calculated from a European ancestry T2DM genome-wide association study by Xue et al. (2018). All models were adjusted for age, sex, education, APOE-ε4 carrier status, and genetic principal components. Multivariable logistic regression was used to test the association between cumulative genetic risk for T2DM and cognitive status. To test inferred causality using Mendelian randomization, we used the inverse variance method.

Results

Among included participants, 20.9% had T2DM and 20.7% had dementia or cognitive impairment. Among European ancestry participants, T2DM was associated with 1.66 times odds of cognitive impairment non-dementia (95% confidence interval: 1.55–1.77) relative to normal cognition. A one standard deviation increase in cumulative genetic risk for T2DM was associated with 1.30 times higher odds of T2DM (95% confidence interval: 1.10–1.52). Cumulative genetic risk for T2DM was not associated with dementia status or cognitive-impaired non-dementia in either ancestry (P > 0.05); lack of association here is an important assumption of Mendelian randomization. Using Mendelian randomization, we did not observe evidence for an inferred causal association between T2DM and cognitive impairment (odds ratio: 1.04; 95% confidence interval: 0.90–1.21).

Discussion

Consistent with prior research, T2DM was associated with cognitive status. Prevention of T2DM and cognitive decline are both critical for public health, however, this study does not provide evidence that T2DM is causally related to impaired cognition. Additional studies in other ancestries, larger sample sizes, and longitudinal studies are needed to confirm these results.

2021 Alzheimer's disease facts and figures

This article describes the public health impact of Alzheimer's disease (AD), including incidence and prevalence, mortality and morbidity, use and costs of care, and the overall impact on caregivers and society. The Special Report discusses the challenges of providing equitable health care for people with dementia in the United States. An estimated 6.2 million Americans age 65 and older are living with Alzheimer's dementia today. This number could grow to 13.8 million by 2060 barring the development of medical breakthroughs to prevent, slow or cure AD. Official death certificates recorded 121,499 deaths from AD in 2019, the latest year for which data are available, making Alzheimer's the sixth-leading cause of death in the United States and the fifth-leading cause of death among Americans age 65 and older. Between 2000 and 2019, deaths from stroke, heart disease and HIV decreased, whereas reported deaths from AD increased more than 145%. This trajectory of deaths from AD was likely exacerbated in 2020 by the COVID-19 pandemic. More than 11 million family members and other unpaid caregivers provided an estimated 15.3 billion hours of care to people with Alzheimer's or other dementias in 2020. These figures reflect a decline in the number of caregivers compared with a decade earlier, as well as an increase in the amount of care provided by each remaining caregiver. Unpaid dementia caregiving was valued at $256.7 billion in 2020. Its costs, however, extend to family caregivers' increased risk for emotional distress and negative mental and physical health outcomes - costs that have been aggravated by COVID-19. Average per-person Medicare payments for services to beneficiaries age 65 and older with AD or other dementias are more than three times as great as payments for beneficiaries without these conditions, and Medicaid payments are more than 23 times as great. Total payments in 2021 for health care, long-term care and hospice services for people age 65 and older with dementia are estimated to be $355 billion. Despite years of efforts to make health care more equitable in the United States, racial and ethnic disparities remain - both in terms of health disparities, which involve differences in the burden of illness, and health care disparities, which involve differences in the ability to use health care services. Blacks, Hispanics, Asian Americans and Native Americans continue to have a higher burden of illness and lower access to health care compared with Whites. Such disparities, which have become more apparent during COVID-19, extend to dementia care. Surveys commissioned by the Alzheimer's Association recently shed new light on the role of discrimination in dementia care, the varying levels of trust between racial and ethnic groups in medical research, and the differences between groups in their levels of concern about and awareness of Alzheimer's disease. These findings emphasize the need to increase racial and ethnic diversity in both the dementia care workforce and in Alzheimer's clinical trials.

Effects of physical activity on cognitive function among patients with diabetes in China: a nationally longitudinal study

Background

We aimed to examine the effect of physical activity on different cognitive domains among patients with diabetes.

Methods

We used two waves of data from the Chinese Health and Retirement Longitudinal Study (CHARLS, 2013–2015), a nationally representative dataset of Chinese population aged over 45. Total physical activity scores were calculated based on the International Physical Activity Questionnaire (IPAQ). Executive function and episodic memory were used as measures of cognitive function. We conducted lagged dependent variable models to explore the association between physical activity and cognitive function in full sample as well as two different age groups (45–65, ≥65). Results: 862 diabetic patients were included. We found that diabetic participants who had greater level of physical activity at baseline were associated with better episodic memory function in 2 years (p < 0.05). Moreover, physical activity was significantly associated with less decline in episodic memory in fully adjusted models, and the associations were stronger among patients aged 45–65 years (p < 0.05). No statistically significant association was found between physical activity and executive function in all age groups.

Conclusions

Physical activity may prevent some of the potential decline in episodic memory in diabetic patients. Clinicians and public health departments should strengthen the promotion of physical activity and develop early screening tools among diabetic participants to prevent the progression of cognitive impairment.

Association between trajectory of severe hypoglycemia and dementia in patients with type 2 diabetes: A population-based study

Background

We aimed to investigate associations between exposure to various trajectories of severe hypoglycemic events and risk of dementia in patients with type 2 diabetes.

Methods

In 2002–2003, 677,618 patients in Taiwan were newly diagnosed as having type 2 diabetes. Among them, 35,720 (5.3%) experienced severe hypoglycemic events during the 3-year baseline period following diagnosis. All patients were followed from the first day after baseline period to the date of dementia diagnosis, death, or the end of 2011. A group-based trajectory model was used to classify individuals with severe hypoglycemic events during the baseline period. Cox proportional hazard models with the competing risk method were used to relate dementia risk to various severe hypoglycemia trajectories.

Results

After a median follow-up 6.70 and 6.10 years for patients with and without severe hypoglycemia at baseline, respectively, 1,952 (5.5%) individuals with severe hypoglycemia and 23,492 (3.7%) without developed dementia during follow-up, for incidence rates of 109.80 and 61.88 per 10,000 person-years, respectively. Four groups of severe hypoglycemia trajectory were identified with a proportion of 18.06%, 33.19%, 43.25%, and 5.50%, respectively, for Groups 1 to 4. Groups 3 (early manifestation but with later decrease) and 4 (early and sustained manifestation) were associated with a significantly increased risk of dementia diagnosis, with a covariate-adjusted subdistribution hazard ratio of 1.22 (95% confidence interval, 1.14–1.31) and 1.25 (95% confidence interval, 1.02–1.54), respectively.

Conclusion

Our analysis highlighted that early manifestation of severe hypoglycemic events may contribute more than does late manifestation to the risk of dementia among individuals newly diagnosed as having type 2 diabetes.

Polyphenols and Cognition In Humans: An Overview of Current Evidence from Recent Systematic Reviews and Meta-Analyses

BACKGROUND

There is increasing interest in the impact of dietary influences on the brain throughout the lifespan, ranging from improving cognitive development in children through to attenuating ageing related cognitive decline and reducing risk of neurodegenerative diseases. Polyphenols, phytochemicals naturally present in a host of fruits, vegetables, tea, cocoa and other foods, have received particular attention in this regard, and there is now a substantial body of evidence from experimental and epidemiological studies examining whether their consumption is associated with cognitive benefits.

OBJECTIVE

The purpose of this overview is to synthesise and evaluate the best available evidence from two sources, namely meta-analyses and systematic reviews, in order to give an accurate reflection of the current evidence base for an association between polyphenols and cognitive benefits.

METHOD

Four meta-analyses and thirteen systematic reviews published between 2017-2020 were included, and were categorised according to whether they reviewed specific polyphenol-rich foods and classes or all polyphenols. A requirement for inclusion was assessment of a behavioural cognitive outcome in humans.

RESULTS

A clear and consistent theme emerged that whilst there is support for an association between polyphenol consumption and cognitive benefits, this conclusion is tentative, and by no means definitive. Considerable methodological heterogeneity was repeatedly highlighted as problematic such that the current evidence base does not support reliable conclusions relating to efficacy of specific doses, duration of treatment, or sensitivity in specific populations or certain cognitive domains. The complexity of multiple interactions between a range of direct and indirect mechanisms of action is discussed.

CONCLUSIONS

Further research is required to strengthen the reliability of the evidence base.

Hypoglycaemia in type 2 diabetes exacerbates amyloid-related proteins associated with dementia

AIMS

Hypoglycaemia in diabetes (T2D) may increase the risk of Alzheimer's disease (AD). We hypothesized that hypoglycaemia-induced amyloid-related protein changes would be exacerbated in T2D.

MATERIALS AND METHODS

A prospective, parallel study in T2D (n = 23) and controls (n = 23). Subjects underwent insulin-induced hypoglycaemia with blood sampling at baseline, hypoglycaemia and post-hypoglycaemia; proteomic analysis of amyloid-related proteins was undertaken.

RESULTS

At baseline, amyloid-precursor protein (APP) (P < .01) was elevated and alpha-synuclein (SNCA) (P < .01) reduced in T2D. At hypoglycaemia, amyloid P-component (P < .01) was elevated and SNCA (P < .05) reduced in T2D; APP (P < .01) and noggin (P < .05) were elevated and SNCA (P < .01) reduced in controls. In the post-hypoglycaemia follow-up period, APP and microtubule-associated protein tau normalized in controls but showed a below-baseline decrease in T2D; noggin normalized in both; SNCA normalized in T2D, with a below-baseline decrease in controls.

CONCLUSION

The AD-associated protein pattern found in T2D, with basal elevated APP and reduced SNCA, was exaggerated by hypoglycaemia with increased APP and decreased SNCA. Additional AD-associated protein levels that changed in response to hypoglycaemia, particularly in T2D, included amyloid P-component, microtubule-associated protein tau, apolipoproteins A1 and E3, pappalysin and noggin. These results are in accordance with the reported detrimental effects of hypoglycaemia.

Impact of metabolic dysfunction on cognition in humans

PURPOSE OF REVIEW

The current review evaluates the recent literature on the impact of metabolic dysfunction in human cognition, focusing on epidemiological studies and meta-analyses of these.

RECENT FINDINGS

Worldwide around 50 million people live with dementia, a number projected to triple by 2050. Recent reports from the Lancet Commission suggest that 40% of dementia cases may be preventable primarily by focusing on well established metabolic dysfunction components and cardiovascular risk factors.

SUMMARY

There is robust evidence that type 2 diabetes and midlife hypertension increase risk of dementia in late life. Obesity and elevated levels of LDL cholesterol in midlife probably increase risk of dementia, but further research is needed in these areas. Physical activity, diet, alcohol, and smoking might also influence the risk of dementia through their effect on metabolic dysfunction. A key recommendation is to be ambitious about prevention, focusing on interventions to promote healthier lifestyles combating metabolic dysfunction. Only comprehensive multidomain and staff-requiring interventions are however efficient to maintain or improve cognition in at-risk individuals and will be unrealistic economic burdens for most societies to implement. Therefore, a risk score that identifies high-risk individuals will enable a targeted early intensive intervention toward those high-risk individuals that will benefit the most from a prevention against cardiovascular risk factors and metabolic dysfunction.

Sleep disorders and risk of dementia in patients with new-onset type 2 diabetes: A nationwide population-based cohort study

BACKGROUND

This study examined the relationship between sleep disorders and the risk of dementia in patients with newly diagnosed type 2 diabetes.

METHODS

This study used the Korean Health Screening Cohort data and included 39 135 subjects aged ≥40 years with new-onset type 2 diabetes between 2004 and 2007, with follow-up throughout 2013. Sleep disorders were measured by F51(sleep disorders not due to a substance or known physiological condition) or G47(sleep disorders) under International Classification of Diseases, Tenth Revision (ICD-10) codes as a primary diagnosis, and the adjusted hazard ratio (AHR) and 95% CI of all-cause dementia, Alzheimer disease, vascular dementia, and other dementia were estimated using multivariable Cox proportional hazards regression models.

RESULTS

In the patients with type 2 diabetes with an age range between 42 and 84 years (M = 57.8, SD = 9.5), this study identified 2059 events of dementia during an average follow-up time of 5.7 years. In patients with type 2 diabetes, subjects with sleep disorders were associated with an increased risk of all-cause dementia (AHR, 1.46; 95% CI, 1.19-1.80), Alzheimer disease (AHR, 1.39; 95% CI, 1.02-1.88), and other dementia (AHR, 1.69; 95% CI, 1.23-2.31) compared to those without sleep disorders. Men (AHR, 1.93; 95% CI, 1.42-2.62) and older adults (AHR, 1.70; 95% CI, 1.35-2.15) with sleep disorders were associated with an increased risk of dementia than their counterparts without sleep disorders among patients with type 2 diabetes.

CONCLUSIONS

These findings suggest that sleep disorders are significantly associated with an increased risk of dementia in patients with new-onset type 2 diabetes.

Diabetes, Brain Infarcts, Cognition, and Small Vessels in the Canadian Alliance for Healthy Hearts and Minds Study

BACKGROUND

Diabetes is a risk factor for cerebrovascular disease and cognitive impairment. The anatomical basis for this is uncertain.

METHODS

The Canadian Alliance for Healthy Hearts and Minds collected brain and carotid magnetic resonance imaging (MRI) and 2 cognitive tests (the Digit Symbol Substitution Test and the Montreal Cognitive Assessment test) in a cross-sectional sample of men and women. Brain MRIs identified brain infarcts (BI), lacunar BI, high white matter hyperintensity (WMH), vascular brain injury (VBI; BI or high WMH), and small vessel VBI (lacunar BI or high WMH). Carotid MRIs estimated carotid wall volume, a measure of subclinical atherosclerosis. Cognitive scores were standardized to each site's mean score, and cognitive impairment was identified by 1 or both test scores ≤1 standard deviation below the site's mean score on that test.

RESULTS

The 7733 participants included 495 participants (6.4%) with diabetes, of whom 388 were taking diabetes drugs. After age and sex adjustment, diabetes was independently associated with BI (odds ratio [OR] 1.53, 95% confidence interval [CI] 1.05, 2.24), VBI (OR 1.64, 95% CI 1.26, 2.13), small vessel VBI (OR 1.67, 95% CI 1.28, 2.19), and cognitive impairment (OR 1.47, 95% CI 1.20, 1.80). The association between diabetes and small vessel VBI persisted after adjustment for cerebrovascular disease risk factors and nonlacunar infarcts (OR 1.52, 95% CI 1.15, 2.01), and the association with cognitive impairment persisted after adjustment for small vessel VBI (OR 1.27, 95% CI 1.03, 1.56).

CONCLUSION

Small vessel disease characterizes much of the relationship between diabetes and VBI. However, additional factors are required to disentangle the relationship between diabetes and cognitive impairment.