Understanding depression in type 2 diabetes: a biological approach in observational studies

Emerging global interest: Unraveling the link between diabetes mellitus and depression

BACKGROUND

Studies have shown a strong bidirectional association between diabetes and depression, with diabetes increasing the risk of developing depression and vice versa. Depression among patients with diabetes is associated with poor glycemic control, complications, and poor self-care.

AIM

To explore the present state of research globally concerning diabetes and depression, to aid understanding the current research landscape and identify potential future areas of research.

METHODS

A bibliometric approach was used, utilizing the Scopus database to gather pertinent research articles released from 2004 to 2023. Analyses encompassed publication patterns, significant contributors, research focal points, prevalent themes, and the most influential articles, aimed at discerning emerging research subjects.

RESULTS

A total of 3229 publications that met the search criteria were identified. A significant increase in the number of publications related to diabetes and depression has been observed in the past two decades. The most productive nation was the USA (n = 1015; 31.43%), followed by China (n = 325; 10.07%), the UK (n = 236; 7.31%), and Germany (n = 218; 6.75%). Three principal themes in research on depression and diabetes were delineated by the analysis. First, the exploration of the elevated prevalence and etiology of this comorbidity; second, the focus on interventions, particularly randomized controlled trials, aimed at enhancing diabetes management among individuals with depression; and finally, the investigation of the involved risk factors and biological mechanisms underlying this bidirectional relationship.

CONCLUSION

There has been a recent surge of interest in the relationship between diabetes and depression. This could aid researchers to identify areas lacking in the literature and shape future research.

Associations between HbA1c Reduction and Change in Depressive Symptoms following Glucose-lowering Treatment in Adults: A Systematic Review of Intervention Studies

INTRODUCTION

Hyperglycemia constitutes a likely pathway linking diabetes and depressive symptoms; lowering glycemic levels may help reduce diabetes-comorbid depressive symptoms. Since randomized controlled trials can help understand temporal associations, we systematically reviewed the evidence regarding the potential association of hemoglobin HbA1c lowering interventions with depressive symptoms.

METHODS

PubMed, PsycINFO, CINAHL, and EMBASE databases were searched for randomized controlled trials evaluating HbA1c-lowering interventions and including assessment of depressive symptoms published between 01/2000-09/2020. Study quality was evaluated using the Cochrane Risk of Bias tool. PROSPERO registration: CRD42020215541.

RESULTS

We retrieved 1,642 studies of which twelve met our inclusion criteria. Nine studies had high and three unclear risks of bias. Baseline depressive symptom scores suggest elevated depressive symptoms in five studies. Baseline HbA1c was <8.0% (<64 mmol/mol) in two, 8.0-9.0% (64-75 mmol/mol) in eight, and ≥10.0% (≥86 mmol/mol) in two studies. Five studies found greater HbA1c reduction in the treatment group; three of these found greater depressive symptom reduction in the treatment group. Of four studies analyzing whether the change in HbA1c was associated with the change in depressive symptoms, none found a significant association. The main limitation of these studies was relatively low levels of depressive symptoms at baseline, limiting the ability to show a lowering in depressive symptoms after HbA1c reduction.

CONCLUSIONS

We found insufficient available data to estimate the association between HbA1c reduction and depressive symptom change following glucose-lowering treatment. Our findings point to an important gap in the diabetes treatment literature. Future clinical trials testing interventions to improve glycemic outcomes might consider measuring depressive symptoms as an outcome to enable analyses of this association.

Mesenchymal Stem Cell-Derived Exosomes: A Novel Approach to Diabetes-Associated Cognitive Impairment

The progression of diabetes frequently results in a myriad of neurological disorders, including ischemic stroke, depression, blood-brain barrier impairment, and cognitive dysfunction. Notably, diabetes-associated cognitive impairment, a prevalent comorbidity during the course of diabetes, progressively affects patients' cognitive abilities and may reciprocally influence diabetes management, thereby severely impacting patients' quality of life. Extracellular vesicles, particularly nanoscale exosomes, have garnered considerable attention in recent years. These exosomes carry and transfer various functional molecules, such as proteins, lipids, and diverse non-coding RNAs, serving as novel regulators and communicators in intercellular interactions. Of particular interest, mesenchymal stem cell-derived exosomes (MSC-Exos) have been reported to traverse the blood-brain barrier and ameliorate intracerebral pathologies. This review elucidates the role of MSC-Exos in diabetes-related cognitive impairment, with a focus on their applications as biomarkers, modulation of neuronal regeneration and synaptic plasticity, anti-inflammatory properties, antioxidative effects, and their involvement in regulating the functionality of β-amyloid proteins during the course of cognitive impairment. The immense therapeutic potential of MSC-Exos in the treatment of diabetes-induced cognitive dysfunction is emphasized.

Long-Term Hyperglycemia Causes Depressive Behaviors in Mice with Hypoactive Glutamatergic Activity in the Medial Prefrontal Cortex, Which Is Not Reversed by Insulin Treatment

The etiology of hyperglycemic-induced depressive behaviors is unclear. We hypothesized that long-term hyperglycemia may induce long-lasting disturbances in glutamatergic signaling and neural damages, causing depressive behaviors. To prove our hypothesis, a C57BL/6N mouse model of hyperglycemia was maintained for 4 weeks (equivalent to approximately 3 years in humans), after which insulin treatment was administered for an additional 4 weeks to normalize hyperglycemia-induced changes. Hyperglycemic mice showed depressive-like behaviors. Glutamatergic neurons and glial cells in the medial prefrontal cortex (mPFC) were affected by hyperglycemia. Insulin treatment improved blood glucose, water intake, and food intake to normoglycemic levels, but did not improve depressive-like behaviors. Glutamatergic signaling decreased with long-term hyperglycemia and did not normalize with insulin-induced normoglycemia. Importantly, hyperglycemia-induced changes in the mPFC were almost not reversed by the 4-week insulin treatment. In particular, levels of insulin receptor beta subunit (IRβ), IRS-1, vesicular glutamate transporter 1, glutamine transporter SNAT2, phosphate-activated glutaminase, and GLUT-3 were not changed by insulin. Nitration and the dephosphorylation of IRβ in the PFC also did not improve with insulin treatment. Therefore, our results suggest that hypoactive glutamatergic activity in the mPFC is involved in diabetic-associated depressive behaviors, and it is difficult to cure with glycemic regulation alone.

The relationship between the knowledge of diabetes mellitus and the mental, psychological and emotional status of T2DM patients based on a structural equation model

To explore diabetes-related knowledge levels among patients with type 2 diabetes mellitus (T2DM) and the influencing factors, correlations and paths of patients' mental and emotional status based on a structural equation model. A total of 1512 patients with T2DM in 18 tertiary general hospitals in Hunan Province. A descriptive correlational study. The study was conducted and surveyed with the general information questionnaires, including the Audit of Diabetes Knowledge (AD knowl), the Problem Areas in Diabetes 5 scale (PAID-5) and the World Health Organization Five-Item Well-Being Index (WHO-5). The structural equation model showed that PAID-5 and WHO-5 scores (P < 0.05) were affected by diabetes self-management, medical history/treatment and knowledge. According to the model, the common risk factors affecting the mental and emotional status of diabetic patients were general demographic characteristics (less exercise time and greater economic burden), medical history/treatment of diabetes (longer course of disease, more hospitalizations due to diabetes, and more acute or chronic complications), and lower levels of diabetes-related knowledge. In addition, solitude was also a risk factor for low levels of happiness. The diabetes-related knowledge levels of T2DM patients are very low, and these patients generally experience emotional disorders, which deserves close attention. The structural equation model can be used to explore the influencing factors and correlations of the psychological and emotional status of diabetic patients.

Risk factors for cognitive decline in type 2 diabetes mellitus patients in Brazil: a prospective observational study

BACKGROUND

Type 2 Diabetes Mellitus (T2DM) patients are twice as likely to develop dementia. The study's goal was to evaluate cognitive performance and risk factors for cognitive decline in this population.

METHODS

Prospective observational study was conducted with 400 T2DM adults, of whom, during routine baseline and follow-up appointments, had socio-demographic, clinical, and laboratory data collected, and underwent physical examination, screening for depression symptoms (Patient Health Questionaire-9-PHQ-9), and cognitive tests: Mini-Mental State Examination (MMSE), Semantic Verbal Fluency Test, Trail Making Test A/B, and Word Memory Tests. Each cognitive test score was converted to a z-score and its average resulted in a new variable called Global Cognitive z-Score [GCS(z)]. Averages of the cognitive test scores and GCS(z) at both moments were compared by the Student's T-Test for paired samples. Multivariate binary logistic regression models were built to assess the association of GCS(z) < zero with risk factors for cognitive decline at the baseline and follow-up.

RESULTS

After exclusions, 251 patients were eligible, being 56.6% female, mean age of 61.1 (± 9.8) years, 12.6 (± 8.9) years of DM duration, and 7.6 (± 4.2) years of school education. Follow-up had 134 patients reevaluated and took place after a mean of 18.4(± 5.0) months. Eleven (14%) patients with a GCS(z) ≥ 0 at baseline turned into a GCS(z) < 0 at follow-up. There were no significant differences between the means of cognitive test scores and GCS(z) at the two evaluation moments. At the baseline, the multivariate logistic regression model identified five risk factors associated with GCS(z) < zero: age ≥ 65 years, schooling ≤ 6 years, arterial hypertension, depression symptoms, and diabetic retinopathy (DR), with odds ratio (OR) and 95% confidence interval (CI95%) respectively: 5.46 (2.42-12.34); 12.19 (5.62-26.46); 2.55 (0.88-7.39); 3.53 (1.55-8.07) e 2.50 (1.18-5.34). At follow-up, the risk factors for GCS(z) < zero were: schooling ≤ 6 years, DM duration ≥ 10 years, depression symptoms, arterial hypertension, and cardiovascular disease (CVD), OR and CI95% respectively: 10.15 (3.68-28.01); 2.68 (0.96-7.48); 4.92 (1.77-13.70); 7.21 (1.38-35.71) e 5.76 (1.93-17.18).

CONCLUSIONS

Based on our results, cognitive evaluation and follow-up should be incorporated on the routine of T2DM patients, especially for those with advanced age, low education level, prolonged DM duration, arterial hypertension, depression symptoms, CVD, and DR.

Cerebral Blood Flow Alterations in Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis of Arterial Spin Labeling Studies

Objective

Arterial spin labeling (ASL) studies have revealed inconsistent regional cerebral blood flow (CBF) alterations in patients with type 2 diabetes mellitus (T2DM). The aim of this systematic review and meta-analysis was to identify concordant regional CBF alterations in T2DM.

Methods

A systematic review was conducted to the published literatures comparing cerebral perfusion between patients with T2DM and healthy controls using ASL. The seed-based d mapping (SDM) was further used to perform quantitative meta-analysis on voxel-based literatures and to estimate the regional CBF alterations in patients with T2DM. Metaregression was performed to explore the associations between clinical characteristics and cerebral perfusion alterations.

Results

A total of 13 studies with 14 reports were included in the systematic review and 7 studies with 7 reports were included in the quantitative meta-analysis. The qualitative review found widespread CBF reduction in cerebral lobes in T2DM. The meta-analysis found increased regional CBF in right supplementary motor area and decreased regional CBF in bilateral middle occipital gyrus, left caudate nucleus, right superior parietal gyrus, and left calcarine fissure/surrounding cortex in T2DM.

Conclusion

The patterns of cerebral perfusion alterations, characterized by the decreased CBF in occipital and parietal lobes, might be the neuropathology of visual impairment and cognitive aging in T2DM.

The association between diabetes mellitus and incidence of depressive episodes is different based on sex: insights from ELSA-Brasil

OBJECTIVE

To investigate the association between diabetes mellitus (DM) and incidence of depressive episodes among men and women.

METHODS

Data were used from 12,730 participants (5866 men and 6864 women) at baseline (2008-2010) and follow-up 1 (2012-2014) of the Longitudinal Study of Adult Health (ELSA-Brasil), a multicenter cohort of Brazilian civil servants. Participants were classified for diabetes using self-reported and clinical information, and evaluated for presence of depressive episodes by the Clinical Interview Schedule-Revised (CIS-R). Associations were estimated by means of logistic regression models (crude and adjusted for socio-demographic variables).

RESULTS

Women classified as with DM prior to the baseline were at 48% greater risk (95% confidence interval (CI) = 1.03-2.07) of depressive episodes in the crude model and 54% greater risk (95% CI = 1.06-2.19) in the final adjusted model compared to women classified as non-DM. No significant associations were observed for men. The regression models for duration of DM and incidence of depressive episodes (n = 2143 participants; 1160 men and 983 women) returned no significant associations.

CONCLUSION

In women classified as with prior DM, the greater risk of depressive episodes suggests that more frequent screening for depression may be beneficial as part of a multi-factorial approach to care for DM.

Pathomechanisms of Vascular Depression in Older Adults

Depression in older individuals is a common complex mood disorder with high comorbidity of both psychiatric and physical diseases, associated with high disability, cognitive decline, and increased mortality The factors predicting the risk of late-life depression (LLD) are incompletely understood. The reciprocal relationship of depressive disorder and age- and disease-related processes has generated pathogenic hypotheses and provided various treatment options. The heterogeneity of depression complicates research into the underlying pathogenic cascade, and factors involved in LLD considerably differ from those involved in early life depression. Evidence suggests that a variety of vascular mechanisms, in particular cerebral small vessel disease, generalized microvascular, and endothelial dysfunction, as well as metabolic risk factors, including diabetes, and inflammation that may induce subcortical white and gray matter lesions by compromising fronto-limbic and other important neuronal networks, may contribute to the development of LLD. The "vascular depression" hypothesis postulates that cerebrovascular disease or vascular risk factors can predispose, precipitate, and perpetuate geriatric depression syndromes, based on their comorbidity with cerebrovascular lesions and the frequent development of depression after stroke. Vascular burden is associated with cognitive deficits and a specific form of LLD, vascular depression, which is marked by decreased white matter integrity, executive dysfunction, functional disability, and poorer response to antidepressive therapy than major depressive disorder without vascular risk factors. Other pathogenic factors of LLD, such as neurodegeneration or neuroimmune regulatory dysmechanisms, are briefly discussed. Treatment planning should consider a modest response of LLD to antidepressants, while vascular and metabolic factors may provide promising targets for its successful prevention and treatment. However, their effectiveness needs further investigation, and intervention studies are needed to assess which interventions are appropriate and effective in clinical practice.

Is there a place for cellular therapy in depression?

Although efforts have been made to improve the pharmacological treatment of depression, approximately one-third of patients with depression do not respond to conventional therapy using antidepressants. Other potential non-pharmacological therapies have been studied in the last years, including the use of mesenchymal stem cell therapies to treat depression. These therapies are reviewed here since it is clinically relevant to develop innovative therapeutics to treat psychiatric patients. Experimental data corroborate that mesenchymal stem cell therapy could be considered a potential treatment for depression based on its anti-inflammatory and neurotrophic properties. However, some clinical trials involving treatment of depression with stem cells are in progress, but with no published results. These studies and other future clinical investigations will be crucial to define how much mesenchymal stem cells can effectively be used in psychiatric clinics as a strategy for supporting depression treatment.

Hemoglobin A1c-levels and subsequent risk of depression in individuals with and without diabetes

BACKGROUND

It has been suggested that long-term glycemic load as reflected in plasma levels of Glycosylated Hemoglobin, Type A1C (HbA1c) is associated with higher risk of depression, however results have been conflicting. We examined the potential association between HbA1c and risk of depression in a large population-based cohort without baseline diabetes (the Glostrup cohort) defined by either self-reported diabetes, registry diagnosis of diabetes or use of antidiabetic medication at baseline and in a national diabetes cohort (the Danish Adult Diabetes Database).

METHODS

A total of 16,124 middle-aged individuals from the Glostrup cohort and 93,544 patients registered in the Danish Adult Diabetes Database were followed from the first registered HbA1c measurement (1999-2014) for subsequent diagnosis of depression or use of antidepressant medication in nation-wide Danish registers. The association was analyzed using a Cox proportional hazards regression model with HbA1c on both a continuous scale using restricted cubic splines and categorized based on the groups found in the spline model. We adjusted for relevant sociodemographic and clinical variables including previous depression and tested for interaction of both gender, insulin use and diabetes type.

RESULTS

During follow-up, 2694 (17%) in the Glostrup cohort and 29,234 (31%) in the diabetes cohort developed depression. In the Glostrup cohort, we found an indication of a positive linear association between HbA1c and depression in women, while no clear association was found in men. In patients with diabetes, we found a U-shaped association between HbA1c and depression in both men and women with the lowest risk estimates for HbA1c levels of 58 mmol/mol (7.5%) in men and of 60 mmol/mol (7.6%) in women. When HbA1c was categorized, men with the highest HbA1c-levels had significantly elevated risk of depression (HR_HbA1c>9.4 1.16 (95%CI 1.10-1.23)) after multifactorial adjustment compared to the reference group with HbA1c of 42.1-56.2 mmol/mol (6.0-7.3%). Women in the lowest and highest category of HbA1c had significantly higher risk of depression HR_HbA1c<6.0 1.15 (95% CI 1.09-1.22) and HR_HbA1c>9.3 1.10 (95% CI 1.04-1.16), respectively, compared to the reference group with HbA1c 42.1-55.0 mmol/mol (7.2-9.3%). There was a significant interaction with gender, but no interaction for insulin use or diabetes type.

CONCLUSIONS

In a population without baseline diabetes, higher HbA1c levels seemed associated with higher depression risk in women, whereas a U-shaped association was found in patients with known diabetes.

Psychiatric disorders as risk factors for type 2 diabetes: An umbrella review of systematic reviews with and without meta-analyses

Having a psychiatric disorder may increase the risk of developing type 2 diabetes[T2D] and this umbrella review aims to determine whether people with a psychiatric disorder have an increased risk of developing T2D and to investigate potential underlying mechanisms. A literature search was performed to identify systematic reviews of longitudinal studies investigating different psychiatric disorders as risk factors for incident T2D in humans (≥18 years). A total of 8612 abstracts were identified, 180 full-text articles were read, and 25 systematic reviews were included. Six categories of psychiatric disorders were identified. Except for eating disorders, all psychiatric disorders were associated with increased risk of incident T2D ranging from RR = 1.18 [95% CI 1.12-1.24] to RR = 1.60 [95% CI 1.37-1.88] for depression; from RR = 1.27 [95% CI 1.19-1.35] to OR = 1.50 [95% CI 1.08-2.10] for use of antidepressant medication; from OR = 1.93 [1.37-2.73] to OR = 1.94 [1.34-2.80] for use of antipsychotic medication; from RR = 1.55 [95% CI 1.21-1.99] to RR = 1.74 [95% CI 1.30-2.34] for insomnia, and finally showed OR = 1.47 [95% CI 1.23-1.75] for anxiety disorders. Plausible underlying mechanisms were discussed, but in most reviews corrections for mechanisms did not explain the association. Notable, only 16% of the systematic reviews had a high methodological quality.

Interaction Between APOE Genotype and Diabetes in Longevity

BACKGROUND

While both apolipoprotein E (APOE) genotype and diabetes affect longevity as well as Alzheimer's disease, their relationship remains to be elucidated.

OBJECTIVE

The current study investigated the potential interaction between diabetes and APOE for lifespan and their relationship with cognitive status.

METHODS

We reviewed the National Alzheimer's Coordinating Center (NACC) dataset, which documents longitudinally clinical records of 24,967 individuals with APOE genotype and diabetic status.

RESULTS

Diabetes was associated with shorter lifespan in APOE3 carriers (n = 12,415, HR = 1.29, 95%CI = 1.17-1.42, p < 0.001) and APOE2 carriers (n = 2,390, HR = 1.37, 95%CI = 1.10-1.69, p = 0.016), while such associations were weaker and not significant in APOE4 carriers (n = 9,490, HR = 1.11, 95%CI = 0.99-1.24, p = 0.162). As there is a significant interactive effect of cognitive status and diabetes on lifespan (p < 0.001), we stratified subjects by cognitive status and observed persistent APOE-dependent harmful effects of diabetes in nondemented individuals but not demented individuals. Notably, questionnaire-based activity status, with which we previously observed an association between APOE genotype and longevity, was also significantly affected by diabetes only in non-APOE4 carriers.

CONCLUSION

The effects of diabetes on longevity vary among APOE genotype. These effects are observed in nondemented individuals and are potentially associated with activity status during their lifespan.

The association of hyperglycaemia and insulin resistance with incident depressive symptoms over 4 years of follow-up: The Maastricht Study

AIMS/HYPOTHESIS

Depression is twice as common in individuals with type 2 diabetes as in the general population. However, it remains unclear whether hyperglycaemia and insulin resistance are directly involved in the aetiology of depression. Therefore, we investigated the association of markers of hyperglycaemia and insulin resistance, measured as continuous variables, with incident depressive symptoms over 4 years of follow-up.

METHODS

We used data from the longitudinal population-based Maastricht Study (n = 2848; mean age 59.9 ± 8.1 years, 48.8% women, 265 incident depression cases, 10,932 person-years of follow-up). We assessed hyperglycaemia by fasting and 2 h post-load OGTT glucose levels, HbA_1c and skin autofluorescence (reflecting AGEs) at baseline. We used the Matsuda insulin sensitivity index and HOMA-IR to calculate insulin resistance at baseline. Depressive symptoms (nine-item Patient Health Questionnaire score ≥10) were assessed at baseline and annually over 4 years. We used Cox regression analyses, and adjusted for demographic, cardiovascular and lifestyle risk factors.

RESULTS

Fasting plasma glucose, 2 h post-load glucose and HbA_1c levels were associated with an increased risk for incident depressive symptoms after full adjustment (HR 1.20 [95% CI 1.08, 1.33]; HR 1.25 [1.08, 1.44]; and HR 1.22 [1.09, 1.37] per SD, respectively), while skin autofluorescence, insulin sensitivity index and HOMA-IR were not (HR 0.99 [0.86, 1.13]; HR 1.02 [0.85, 1.25]; and HR 0.93 [0.81, 1.08], per SD, respectively).

CONCLUSIONS/INTERPRETATION

The observed temporal association between hyperglycaemia and incident depressive symptoms in this study supports the presence of a mechanistic link between hyperglycaemia and the development of depressive symptoms. Graphical abstract.

Curcumin administration and the effects on psychological status and markers of inflammation and oxidative damage in patients with type 2 diabetes and coronary heart disease

INTRODUCTION

This study assessed the effects of curcumin intake on psychological status, markers of inflammation and oxidative damage in patients with type 2 diabetes mellitus (T2DM) and coronary heart disease (CHD).

METHOD

This randomized, double-blind, placebo-controlled trial was performed in 60 patients with T2DM and CHD, aged 45-85 years with 2- and 3-vessel CHD. Patients were randomized into two groups to receive either 1000 mg/day curcumin (n = 30) or placebo (n = 30) for 12 weeks. Using RT-PCR method, gene expression related to insulin metabolism and inflammatory markers on mononuclear cells from peripheral blood was evaluated.

RESULT

Curcumin intake significantly decreased Pittsburgh Sleep Quality Index (PSQI) (β -1.27; 95% CI, -2.27, -0.31; P = 0.01) compared to the placebo group. Curcumin intake caused a significant reduction in malondialdehyde (MDA) (β -0.20 μmol/L; 95% CI, -0.36, -0.04; P = 0.01), significant increase in total antioxidant capacity (TAC) (β 75.82 mmol/L; 95% CI, 3.400, 148.25; P = 0.04) and glutathione (GSH) levels (β 63.48 μmol/L; 95% CI, 26.58, 100.37; P = 0.001) when compared with the placebo. Additionally, curcumin intake upregulated peroxisome proliferator-activated receptor gamma (PPAR-γ) (P = 0.01).

CONCLUSION

Curcumin intake for 12 weeks in patients with T2DM and CHD had beneficial effects on PSQI, TAC, GSH, MDA values, and gene expression of PPAR-γ. This study was retrospectively registered in the Iranian website (www.irct.ir) for registration of clinical trials (http://www.irct.ir: IRCT20170513033941N63).

Cerebral microvascular complications of type 2 diabetes: stroke, cognitive dysfunction, and depression

Adults with type 2 diabetes are at an increased risk of developing certain brain or mental disorders, including stroke, dementia, and depression. Although these disorders are not usually considered classic microvascular complications of diabetes, evidence is growing that microvascular dysfunction is one of the key underlying mechanisms. Microvascular dysfunction is a widespread phenomenon in people with diabetes, including effects on the brain. Cerebral microvascular dysfunction is also apparent in adults with prediabetes, suggesting that cerebral microvascular disease processes start before the onset of diabetes. The microvasculature is involved in the regulation of many cerebral processes that when impaired predispose to lacunar and haemorrhagic stroke, cognitive dysfunction, and depression. Main drivers of diabetes-related cerebral microvascular dysfunction are hyperglycaemia, obesity and insulin resistance, and hypertension. Increasing amounts of data from observational studies suggest that diabetes-related microvascular dysfunction is associated with a higher risk of stroke, cognitive dysfunction, and depression. Cerebral outcomes in diabetes might be improved following treatments targeting the pathways through which diabetes damages the microcirculation. These treatments might include drugs that reduce dicarbonyl compounds, augment cerebral insulin signalling, or improve blood-brain barrier permeability and cerebral vasoreactivity.