Diabetes mellitus and risks of cognitive impairment and dementia: A systematic review and meta-analysis of 144 prospective studies

Scientometric analysis and historical review of diabetic encephalopathy research: Trends and hotspots (2004-2023)

BACKGROUND

Diabetic encephalopathy (DE) is a common and serious complication of diabetes that can cause death in many patients and significantly affects the lives of individuals and society. Multiple studies investigating the pathogenesis of DE have been reported. However, few studies have focused on scientometric analysis of DE.

AIM

To analyze literature on DE using scientometrics to provide a comprehensive picture of research directions and progress in this field.

METHODS

We reviewed studies on DE or cognitive impairment published between 2004 and 2023. The latter were used to identify the most frequent keywords in the keyword analysis and explore the hotspots and trends of DE.

RESULTS

Scientometric analysis revealed 1308 research papers on DE, a number that increased annually over the past 20 years, and that the primary topics explored were domain distribution, knowledge structure, evolution, and emergence of research topics related to DE. The inducing factors, comorbidities, pathogenesis, treatment, and animal models of DE help clarify its occurrence, development, and treatment. An increasing number of studies on DE may be a result of the recent increase in patients with diabetes, unhealthy lifestyles, and unhealthy eating habits, which have aggravated the incidence of this disease.

CONCLUSION

We identified the main inducing factors and comorbidities of DE, though other complex factors undoubtedly increase social and economic burdens. These findings provide vital references for future studies.

Association between hospital-treated infectious diseases and risk of neurodegenerative disease among patients with prediabetes and diabetes: A prospective cohort study in UK Biobank

BACKGROUND

Previous evidence suggests that infectious diseases may contribute to the development of neurodegenerative diseases (NDDs) while individuals with hyperglycemia may be at increased risk for both infection and NDDs due to dysregulated inflammation levels. This study aimed to examine the association between hospital-treated infectious diseases and the risk of NDDs among patients with prediabetes and diabetes and whether the associations differed by the number of infections and potential effect modifiers.

STUDY DESIGN AND METHOD

Using data from the UK Biobank, we conducted a prospective study involving 69,731 individuals, consisting of 48,149 participants with prediabetes and 21,582 participants with diabetes. Hospital-treated infectious diseases and NDDs were identified through record linkage to Health Episode Statistics and the Scottish Morbidity Records. Cox regression models were applied to assess the association between hospital-treated infectious diseases and the risk of developing NDDs, and to evaluate the trend of this association in relation to the number of infections. The modification effects by age, sex, smoking status, alcohol consumption, sleep duration, body mass index (BMI), glycated hemoglobin (HbA1c) levels, comorbidities, and diabetes medication use were investigated.

RESULTS

Over a median follow-up of 10.75 years, 1,867 participants (2.57 per 1,000 person-years) were diagnosed with NDDs. We found hospital-treated infectious diseases were significantly associated with an increased risk of NDDs among both individuals with prediabetes or diabetes (adjusted HR [aHR] 3.11, 95 % CI 2.83-3.42). Specifically, hospital-treated infectious diseases were associated with a higher risk of developing Alzheimer's disease, vascular dementia, all-cause dementia, Parkinson's disease, and multiple sclerosis. Moreover, a greater number of infection diagnoses was associated with a higher risk of NDDs. Consistent associations between infection and an increased risk of NDDs were observed, regardless of factors representing age, sex, lifestyle, and diabetes severity.

CONCLUSIONS

Hospital-treated infectious diseases were significantly associated with the risk of NDDs in individuals with diabetes and prediabetes, with similar associations observed for bacterial and viral infections. These findings emphasize the importance of implementing infection prevention strategies and monitoring of infectious comorbidities in the management of NDDs among patients with prediabetes and diabetes.

Diabetes and coronary artery disease as risk factors for dementia

AIMS

Diabetes is associated with an increased risk of dementia, but it is still debated to which degree this risk depends on the presence of atherosclerotic cardiovascular disease (CVD). In this study, we hypothesize that patients with diabetes and coexisting coronary artery disease (CAD), as a marker of systemic atherosclerotic CVD, have a substantially higher risk of developing dementia.

METHODS AND RESULTS

Patients ≥65 years, who underwent coronary angiography, were stratified by diabetes and CAD. Outcomes were all-cause dementia, Alzheimer's dementia, and vascular dementia. We estimated adjusted hazard ratios (aHRs) using patients with neither diabetes nor CAD as a reference. A total of 103 859 patients were included. Of these, 23 189 (22%) had neither diabetes nor CAD, 3876 (4%) had diabetes, 61 020 (59%) had CAD, and 15 774 (15%) had diabetes and CAD. During a median follow-up of 6.3 years, 5592 (5.5%) patients were diagnosed with all-cause dementia. Patients with diabetes and CAD had the highest HR of all-cause dementia [aHR 1.37, 95% confidence interval (CI) 1.24-1.51], including Alzheimer's dementia (aHR 1.41, 95% CI 1.23-1.62) and vascular dementia (aHR 2.03, 95% CI 1.69-2.45). Patients with diabetes alone (aHR 1.14, 95% CI 0.97-1.33) or CAD alone (aHR 1.11, 95% CI 1.03-1.20) had a modestly increased rate of all-cause dementia.

CONCLUSION

The combination of diabetes and CAD is associated with an increased rate of dementia, in particular vascular dementia, suggesting that the diabetes-related risk of dementia is partly mediated through concomitant atherosclerotic CVD. This underscores the importance of atherosclerotic CVD prevention in diabetic patients to reduce cognitive decline.

A network analysis of depressive symptoms and cognitive performance in older adults with multimorbidity: A nationwide population-based study

BACKGROUND

Depression and cognitive impairment are prevalent mental health issues. Older adults in China exhibits a higher prevalence of multimorbidity, which is linked to an increased risk of depression and cognitive impairment. This study aims to investigate association between depressive symptoms and cognitive impairment in older adults with multimorbidity using network analysis, and to identify important bridge symptoms as potential intervention targets.

METHOD

The study included 5729 individuals aged 60 years and above with multimorbidity, drawn from the China Health and Retirement Longitudinal Survey (CHARLS) dataset. Depressive symptoms and cognitive performance were assessed utilizing the CESD-10 (10-item Center for Epidemiologic Studies Depression) and MMSE (Mini Mental State Examination) scales, respectively. We constructed a network structure of depressive symptoms and cognitive performance, and calculated index of strength and bridge strength for each symptom. Furthermore, a comparative analysis of the network structure across gender and age groups were conducted.

RESULTS

D3 (Felt depressed), C1 (Orientation), and D10 (Could not get going) were identified as the central symptoms of the depressive symptoms - cognitive performance network. C1 (Orientation), C5 (Linguistic skills), and D10 (Could not get going) were bridge symptoms connecting the two illnesses. Moreover, significant differences in edge weights were observed across gender and age groups.

CONCLUSIONS

The central symptoms and bridge symptoms in the network may represent the most effective intervention pathway for addressing cognitive impairment and depression in older adults with multimorbidity. Clinical interventions should properly focus on gender and age differences in symptom presentation.

The Diabetic Cognitive Impairment Score for Early Screening of Cognitive Impairment in Type 2 Diabetes Patients

Purpose: Diabetes has been associated with an excess risk of cognitive impairment. The hyperphosphorylation of tau protein leads to neurodegeneration and is closely related to Type 2 diabetes (T2D). This study aimed to characterize the association between P-tau181 and diabetic cognitive impairment and to develop a nomogram-based score to screen cognitive impairment in T2D patients. Methods: We used a cohort of 379 patients diagnosed with T2D as a training dataset to develop a predictive model. Risk factors associated with cognitive impairment were identified using stepwise multivariate logistic regressive analysis. A nomogram was established by incorporating these risk factors, and the diabetic cognitive impairment score (DCIS) was built and externally validated in another cohort. Results: In the training cohort, patients with cognitive impairment had higher levels of P-tau181 (13.3 [10.5-18.7] vs. 10.0 [8.0-13.0], p < 0.001). P-tau181 was negatively correlated with MOCA (r = -0.308, p < 0.001) and MMSE (r = -0.289, p < 0.001), and it was independently associated with cognitive impairment in T2D patients (OR, 1.137 [95% CI, 1.080-1.198]; p < 0.001). Other independent risk factors of diabetic cognitive impairment included age, education level, and diabetic retinopathy. The DCIS was built by nomogram based on the four risk factors, which had an area under the receiver operating characteristic curve (AUC) of 0.795 (95% CI, 0.751-0.840). The optimal cut-off of DCIS for the diagnosis of cognitive impairment in T2D patients was 139.5, with a sensitivity of 72.9% and a specificity of 75.3%. In the validation cohort, the AUC of DCIS for screening diabetic cognitive impairment was 0.770 (95% CI, 0.716-0.824). Conclusions: P-tau181 was independently associated with diabetic cognitive impairment. The DCIS, based on P-tau181, age, education level, and diabetic retinopathy, is effective to identify cognitive impairment in T2D patients.

Factors associated with cognitive function outcomes among older adults in Kuwait: A cross-sectional study

BACKGROUND

The number of people living with dementia and/or cognitive impairment worldwide is rising with a negative effect on quality of life for many older adults. This study aims to examine the factors associated with cognitive function among older adults in Kuwait.

METHODS

This cross-sectional study recruited 253 older adults ≥ 60 years from a Geriatric outpatient unit in Kuwait. Cognitive function (dependent variable) was assessed using the Arabic version of the Mini-Mental State Examination (MMSE) with scores < 24 indicative of cognitive impairment. Biochemical, nutritional, clinical, lifestyle, anthropometric, and sociodemographic independent variables were included.

RESULTS

A normal MMSE score was reported for 51.0% (n = 129) of the sample, with 34.7% and 14.2% of participants having mild and moderate/severe cognitive impairment, respectively. Multivariate ordinal logistic regression analysis indicated that Type 2 diabetes was associated with more than double the odds of cognitive impairment (OR = 2.15, 95% CI: 1.19-3.94; P = 0.01). Each additional level of education was associated with a lower likelihood of cognitive impairment (OR = 0.34, 95% CI: 0.26-0.43; P < 0.001).

CONCLUSION

This study identifies key risk factors associated with cognitive impairment in older Kuwaiti adults. These findings underscore the need for targeted interventions to mitigate cognitive decline in aging populations and provide context-specific data to support policy decisions.

Modifiable risk factors for stroke, dementia and late-life depression: a systematic review and DALY-weighted risk factors for a composite outcome

BACKGROUND

At least 60% of stroke, 40% of dementia and 35% of late-life depression (LLD) are attributable to modifiable risk factors, with great overlap due to shared pathophysiology. This study aims to systematically identify overlapping risk factors for these diseases and calculate their relative impact on a composite outcome.

METHODS

A systematic literature review was performed in PubMed, Embase and PsycInfo, between January 2000 and September 2023. We included meta-analyses reporting effect sizes of modifiable risk factors on the incidence of stroke, dementia and/or LLD. The most relevant meta-analyses were selected, and disability-adjusted life year (DALY) weighted beta (β)-coefficients were calculated for a composite outcome. The β-coefficients were normalised to assess relative impact.

RESULTS

Our search yielded 182 meta-analyses meeting the inclusion criteria, of which 59 were selected to calculate DALY-weighted risk factors for a composite outcome. Identified risk factors included alcohol (normalised β-coefficient highest category: -34), blood pressure (130), body mass index (70), fasting plasma glucose (94), total cholesterol (22), leisure time cognitive activity (-91), depressive symptoms (57), diet (51), hearing loss (60), kidney function (101), pain (42), physical activity (-56), purpose in life (-50), sleep (76), smoking (91), social engagement (53) and stress (55).

CONCLUSIONS

This study identified overlapping modifiable risk factors and calculated the relative impact of these factors on the risk of a composite outcome of stroke, dementia and LLD. These findings could guide preventative strategies and serve as an empirical foundation for future development of tools that can empower people to reduce their risk of these diseases.

PROSPERO REGISTRATION NUMBER

CRD42023476939.

Adaptation of the Florida Cognitive Activities Scale for Latinx adults with chronic diseases

BACKGROUND

Latinx adults experience disparately high rates of chronic diseases and cognitive dysfunction. Participating in cognitive-stimulating activities, such as reading, is thought to improve and preserve cognitive function. However, little is known about cognitively stimulating activities preferred by Latinx adults. In addition, surveys to measure participation in cognitively stimulating activities are not culturally sensitive to Latinx preferences and tend to feature activities that require financial resources and leisure time and may not include cognitively stimulating activities that are more accessible or preferable.

METHODS

We conducted an instrumentation study in three phases to adapt the Florida Cognitive Activities Scale (FCAS): Phase (1) revision and translation of the FCAS for Latinx adults with chronic diseases; Phase (2) feasibility testing; and Phase (3) reliability and validity testing.

RESULTS

Five experts provided input on existing items, with suggestions for changes or items to remove and for new items. The resulting 17 item FCAS-Latinx (FCAS-L) was translated into Spanish and back-translated and determined to be readable at the 6th grade level. The FACS-L was administered to 70 participants (mean age 62.17 years; 57% female; 51% Mexican American) with other surveys that measured cognitive functioning and chronic disease management. To select the final items, we analyzed the item discrimination index, item-to-total correlations, and participants' feedback. The final 20-item Spanish - and English versions of the FCAS-L are internally consistent (Cronbach alpha = 0.74 and 0.81, respectively), showed good construct validity (higher scores on cognitive functioning tests correlated with engaging in more frequent cognitively stimulating activities, r = 0.63, P < .01), and temporal reliability (the interclass correlation coefficient between test and retest times was 0.81).

CONCLUSION

The FCAS-L is a valid and reliable updated measure of cognitively stimulating activities for Spanish- and English-speaking Latinx adults with chronic conditions.

Education level and health profile related to global cognitive impairment in an urban community in West Jakarta, Indonesia

OBJECTIVES

This study aims to investigate the association of global cognitive with chronic conditions, physical impairment, olfactory function, socio-demographics and other factors among older adults in the urban community, West Jakarta.

MATERIALS AND METHODS

The cross-sectional study involved 334 older adults aged 60 years and older who resided in urban community Jakarta, Indonesia. Trained interviewers visited and evaluated the respondents in the sub-district office. Cognitive function is examined using Montreal Cognitive Assessment-Indonesian Version (MoCA-INA). Respondents were clinically examined using a standardized protocol, which included medical history, general physical examination, cognitive assessment, and blood test for diabetes.

RESULTS

Global cognitive impairment was significantly associated with being female (adjusted odd ratio [AOR]: 1.99, 95% CI: 1.14-3.50) and low education (AOR: 4.79, 95% CI: 2.80-8.18). Moreover diabetes, impaired balance, and olfactory dysfunction have AOR:3.23 (95% CI: 1.39-7.51), 2.55% (95% CI: 1.07-6.07), and 2.26 (95% CI: 1.32-3.85) respectively.

CONCLUSION

This paper highlights that cognitively impaired and diabetic as well as low education subject in urban community, West Jakarta, Indonesia. Global cognitive impairment was associated with being female, having obtained low levels of education, having diabetes, impaired balance and olfactory dysfunction.

Inflammation levels in type 2 diabetes mellitus patients with mild cognitive impairment: Assessment followed by amelioration via dapagliflozin therapy

AIMS

To investigate systemic inflammation and the effect of dapagliflozin treatment in (type 2 diabetes mellitus) T2DM patients with mild cognitive impairment (MCI).

METHODS

Between January and December 2023, 200 participants were recruited from the Department of Endocrinology of Hefei First People's Hospital. Baseline data collected included medical history, fasting blood glucose, HbA1c, liver and kidney function, lipid profiles, IL-1β, TNF-α, sVCAM-1 level, and the urinary albumin-creatinine ratio (uACR). Based on their Montreal Cognitive Assessment Scale (MoCA) scores, these participants were categorized into two groups: 127 in the MCI group and 73 in the non-MCI group. MCI group received dapagliflozin (10 mg daily) alongside standard treatment.

RESULTS

The MCI group showed higher age, height, weight, BMI, HbA1c, FBG, disease duration, carotid plaques, stenosis rates, and elevated IL-1β, TNF-α, and sVCAM-1. MoCA scores were significantly lower in the MCI group. Correlation analysis showed a negative correlation of MoCA scores with IL-1β, TNF-α, sVCAM-1, plaques, stenosis, FBG, and HbA1c, and a positive correlation with height. Binary logistic regression identified age, BMI, IL-1β, sVCAM-1, and FBG as predictors of cognitive impairment in T2DM. Dapagliflozin treatment reduced BMI, HbA1c, inflammatory markers, and FBG, improving MoCA scores.

CONCLUSION

Dapagliflozin treatment may improve cognitive function by reducing inflammation.

Association between sleep quality and mild cognitive impairment in Chinese patients with type 2 diabetes mellitus: a cross-sectional study

BACKGROUND

Globally, the number of individuals with type 2 diabetes mellitus (T2DM) is increasing, and they are at a higher risk of developing mild cognitive impairment (MCI) than the general population. Sleep quality is thought to be a modifiable factor that may contribute to MCI, as previous studies have linked it to cognitive function in older adults. However, evidence concerning the association between sleep quality and MCI among patients with T2DM in China is limited. Therefore, this study aims to identify the association between sleep quality and MCI among patients with T2DM in China.

METHODS

This cross-sectional study was conducted among patients with T2DM who were referred to the Endocrinology Department of Xiangya Hospital, Central South University. Data regarding sociodemographic characteristics, lifestyle factors, T2DM-related information, and biochemical indicators were collected. Sleep quality and MCI were evaluated using the Pittsburgh Sleep Quality Index (PSQI) and the Mini-Mental State Examination (MMSE) scale, respectively. The association between sleep quality and MCI was analyzed using univariate and multivariate analyses.

RESULTS

This study included 1,001 patients with T2DM, with a mean age of 60.2 (standard deviation: 10.1) years. Pearson's correlation analysis showed that the total PSQI score was negatively associated with the MMSE score (r=-0.27, P < 0.05). Multivariate analyses based on four models consistently showed that those with higher total PSQI score (aOR = 1.09-1.11, P < 0.05), as well as higher scores on the subjective sleep quality (aOR = 1.32-1.46, P < 0.05), sleep latency (aOR = 1.25-1.32, P < 0.05), sleep duration (aOR = 1.30-1.32, P < 0.05), sleep efficiency (aOR = 1.36-1.41, P < 0.05), sleep disturbance (aOR = 1.66-1.86, P < 0.05), and daily dysfunction (aOR = 1.38-1.48, P < 0.05) were associated with higher rates of MCI.

CONCLUSIONS

Among Chinese patients with T2DM, poor overall sleep quality, subjective sleep quality, sleep latency, sleep duration, sleep efficiency, sleep disturbance, and daily dysfunction were associated with higher rates of MCI. Future studies are needed to examine whether sleep intervention could improve cognitive function in patients with T2DM. It is also suggested for clinicians working with T2DM patients to raise the awareness of cognitive impairment and sleep problems.

Pregnancy as a window of opportunity for dementia prevention: a narrative review

Dementia is a debilitating condition with a disproportionate impact on women. While sex differences in longevity contribute to the disparity, the role of the female sex as a biological variable in disease progression is not yet fully elucidated. Metabolic dysfunctions are drivers of dementia etiology, and cardiometabolic diseases are among the most influential modifiable risk factors. Pregnancy is a time of enhanced vulnerability for metabolic disorders. Many dementia risk factors, such as hypertension or blood glucose dysregulation, often emerge for the first time in pregnancy. While such cardiometabolic complications in pregnancy pose a risk to the health trajectory of a woman, increasing her odds of developing type 2 diabetes or chronic hypertension, it is not fully understood how this relates to her risk for dementia. Furthermore, structural and functional changes in the maternal brain have been reported during pregnancy suggesting it is a time of neuroplasticity for the mother. Therefore, pregnancy may be a window of opportunity to optimize metabolic health and support the maternal brain. Healthy dietary patterns are known to reduce the risk of cardiometabolic diseases and have been linked to dementia prevention, yet interventions targeting cognitive function in late life have largely been unsuccessful. Earlier interventions are needed to address the underlying metabolic dysfunctions and potentially reduce the risk of dementia, and pregnancy offers an ideal opportunity to intervene. This review discusses current evidence regarding maternal brain health and the potential window of opportunity in pregnancy to use diet to address neurological health disparities for women.

Interactions between menopause and high-fat diet on cognition and pathology in a mouse model of Alzheimer's disease

INTRODUCTION

Post-menopausal women constitute about two-thirds of those with Alzheimer's disease (AD). Menopause increases dementia risk by heightening the likelihood of metabolic disease, a well-known risk factor for dementia. We aimed to determine the effects of menopause and high-fat diet (HF) on cognitive and pathological outcomes in an AD mouse model.

METHODS

At 3 months old, AppNL-F mice received 4-vinylcyclohexene diepoxide (menopause model) or vehicle and were placed on a control (10% fat) or an HF diet (60% fat) until 10 months old.

RESULTS

An interaction between HF diet and menopause led to impaired recognition memory. No effects of menopause were observed on amyloid pathology. However, menopause induced alterations in microglial response, white matter, and hippocampal neurogenesis.

DISCUSSION

This work highlights the need to model endocrine aging in animal models of dementia and contributes to further understanding of the interaction between menopause and metabolic health in the context of AD.

HIGHLIGHTS

The combination of menopause and HF diet led to early onset of cognitive impairment. HF diet increased amyloid pathology in the hippocampus. Menopause led to an increase in microglia density and a decrease in myelin in the corpus callosum. Menopause altered hippocampal neurogenesis in a diet-dependent manner.

The association between diabetes mellitus and postoperative cognitive dysfunction: a systematic review and meta-analysis

BACKGROUND

Postoperative cognitive dysfunction (POCD) is a typical consequence following surgery, particularly in cardiac surgeries. Despite its high incidence, the underlying etiology remains unclear. While diabetes mellitus (DM) has been associated with cognitive impairment, its specific function in POCD development remains unidentified. This study aims to evaluate the connection between DM and the risk of POCD.

METHODS

We conducted a comprehensive search of PubMed, Embase, Web of Science, and the Cochrane Library databases for studies of DM and risk with POCD, collecting data up to 14 September 2023. We assessed publication bias, heterogeneity, and study quality, adhering to PRISMA and AMSTAR guidelines.

RESULTS

Our study comprised 38 trials involving 8748 individuals, with 7734 patients undergoing follow-up. The pooled results showed that individuals with DM had an increased incidence of POCD compared to nondiabetic individuals (RR: 1.44, 95% CI: 1.26-1.65). The incidence of POCD was significantly higher in the group of patients with an average age older than 65 years (RR: 1.69, 95% CI: 1.30-2.20) compared with diabetic patients with an average age younger than 65 years (RR: 1.29, 95% CI: 1.09-1.64). Compared with diabetic patients undergoing cardiac surgery (RR: 1.33, 95% CI: 1.15-1.53), patients receiving non-cardiac surgery showed a greater incidence of POCD (RR: 2.01, 95% CI: 1.43-2.84).

CONCLUSION

Current evidence underscores that diabetic patients face a significantly higher risk of POCD compared to their nondiabetic counterparts. Further research is warranted to clarify the precise mechanisms of this relationship and explore potential preventive strategies for diabetic patients.

Revisiting the Montreal Cognitive Assessment in a European cohort of elderly living with type 2 diabetes

BackgroundIndividuals with type 2 diabetes have an increased risk of developing both vascular and Alzheimer's dementia.ObjectiveThis prospective cross-sectional study assessed the screening ability of the standard Montreal Cognitive Assessment (MoCA) score suggestive of mild cognitive impairment (<26) in a European cohort of individuals ≥65 of age with type 2 diabetes.MethodsParticipants of RECOGNISED, a European prospective EU-funded cohort study, were screened using MoCA. In addition, a 13-item Neuropsychological Test Battery (NTB) with the Clinical Dementia Rating was undertaken to categorize participants as normocognitive (NC, n = 128) or mild cognitive impaired (MCI, n = 185). Receiver operating characteristic (ROC) analysis was used to evaluate the ability of MoCA cut-off scores to categorize patients as having MCI or not.ResultsThe standard MoCA cut-off of 25/26 demonstrated a sensitivity of 88% and a specificity of 51%, resulting in a false positive rate of 20%. ROC analysis showed that a MoCA cut-off of 24/25 has a better balance between sensitivity (81%) and specificity (62%), with a lower false positive rate of 16%. NTB results showed that the MCI group had the lowest norm-referenced percentile scores in the visuo-construction domain, a known early feature of Alzheimer's disease and a significant predictor of a rapid rate of disease progression.ConclusionsMoCA as a screening tool in individuals ≥65 with type 2 diabetes, overestimates the prevalence of MCI, even when applying lower cut-offs. More specific screening strategies are necessary, particularly targeting the visuo-construction domain, to effectively identify cognitive impairment in individuals with type 2 diabetes.

Geriatric Syndromes in Older Adults With and Without Diabetes: A Systematic Review and Meta-Analysis

PURPOSE

Diabetes prevalence is increasing among older adults globally. The current study aimed to compare geriatric syndrome prevalence in older adults with and without diabetes.

METHOD

Primary research (2011 to 2024) in English, French, or Spanish was included. We used multiple databases following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Pooled log odds ratios (ORs) and prevalence rates were calculated using random-effects models. Sensitivity analysis explored heterogeneity, and publication bias was assessed.

RESULTS

Older adults with diabetes exhibited higher prevalence rates of cognitive impairment (9.13% vs. 4.22%, log OR: 0.1884), depression (8.96% vs. 5.44%, log OR: 0.3543), falls (11.5% vs. 4.47%, log OR: 0.4237), functional impairment (14.2% vs. 10.6%, log OR: 1.02), urinary incontinence (9.72% vs. 4.35%, log OR: 1.3668), frailty (22.8% vs. 12.1%, log OR: 1.3443), and polypharmacy (22.9% vs. 5.78%, log OR: 2.5420). Diabetes was also associated with a higher comorbidity burden.

CONCLUSION

Multidisciplinary strategies addressing diabetes and associated conditions are crucial for older adults with diabetes. Future research should delve into underlying mechanisms and optimize care strategies. [Research in Gerontological Nursing, 18(2), 99-108.].

Peripheral mitochondrial transplantation alleviates diabetes-associated cognitive dysfunction by suppressing cuproptosis

Mitochondrial dysfunction and neuronal impairment are hallmark features of Diabetes-Associated Cognitive Dysfunction (DACD), mitochondrial transplantation is also a therapeutic intervention for DACD. However, the precise mechanism underlying its therapeutic effects are not fully elucidated. Given that imbalances in copper homeostasis and cuproptosis are associated with various neurodegenerative disorders and diabetic myocardial damage, we hypothesize a role for cuproptosis in the pathogenesis of DACD. We further propose that therapeutic peripheral mitochondrial transplantation may ameliorate DACD by reducing processes of cuproptosis. In this research, the study delved into the expression levels of cuproptosis-associated proteins FDX1, LIAS, and DLAT, as well as the copper content in both type 2 diabetes mellitus (T2DM) mice and primary neuronal cells exposed to high glucose and palmitic acid (HG/Pal). Furthermore, the cognitive capabilities of the mice were evaluated using a series of behavioral tests. The findings revealed that in primary neurons exposed to HG/Pal, the expression of copper levels was elevated, and the levels of FDX1, LIAS, and DLAT were reduced. Post-transplantation of platelet-derived mitochondria (Mito-Plt), a significant reversal of these biomarkers was noted, coincident with an improvement in cognitive deficits in T2DM mice. Significantly, the cuproptosis agonist elesclomol (ES) aggravated these alterations. In summary, the findings collectively suggest a causal connection between DACD and the development of cuproptosis in neurons. The use of exogenous Mito-Plt presents a promising therapeutic approach, capable of rescuing neurons from cuproptosis and thereby potentially alleviating DACD.

Heterogeneous blood pressure treatment effects on cognitive decline in type 2 diabetes: A machine learning analysis of a randomized clinical trial

AIM

We aimed to identify the characteristics of patients with diabetes who can derive cognitive benefits from intensive blood pressure (BP) treatment using machine learning methods.

MATERIALS AND METHODS

Using data from the Action to Control Cardiovascular Risk in Diabetes Memory in Diabetes (ACCORD-MIND) study, 1349 patients with type 2 diabetes who underwent BP treatment (intensive treatment targeting a systolic BP <120 mmHg vs. standard treatment targeting <140 mmHg) were included in the machine learning analysis. Seventy-nine variables correlated with diabetes and cognitive function were used to build the causal forest and causal tree models for identifying heterogeneous BP treatment effects on cognitive decline.

RESULTS

Our analyses identified four variables including urinary albumin-to-creatinine ratio (UACR, mg/g), Framingham 10-year cardiovascular risk score (FRS, %), triglycerides (TG, mmol/L) and diabetes duration, that categorized the participants into five subgroups with different risk benefits for cognitive decline from BP treatments. Subgroup 1 (UACR ≥65 mg/g) had an absolute risk reduction (ARR) of 15.36% (95% CI, 5.01%-25.46%) from intensive versus standard BP treatment (hazard ratio [HR], 0.36; 95% CI, 0.18-0.73). Subgroup 2 (UACR <65 mg/g, FRS ≥26%, TG <2.3 mmol/L and diabetes duration ≥9 years) had an ARR of 14.74% (95% CI, 4.56%-24.59%) from intensive versus standard BP treatment (HR, 0.34; 95% CI, 0.15-0.77). No significant benefits were found for other subgroups.

CONCLUSIONS

Patients with type 2 diabetes with high UACR, or with low UACR and low TG, but high predicted cardiovascular risk and long diabetes duration were likely to derive cognitive benefits from intensive BP treatment.

Hesperetin-Enhanced Metformin to Alleviate Cognitive Impairment via Gut-Brain Axis in Type 2 Diabetes Rats

Diabetes constitutes a risk factor for cognitive impairment, whereas insulin resistance serves as the shared pathogenesis underlying both diabetes and cognitive decline. The use of metformin for treating cognitive impairment remains controversial. The present study found that hesperetin, a flavanone derived from citrus peel, enhanced metformin's efficacy in reducing blood sugar levels, improving insulin sensitivity, and ameliorating cognitive impairment in diabetic rats. Additionally, it reduced the required dosage of metformin to one-third of its conventional dose. Transcriptome analysis and 16S rRNA sequencing revealed that the activation of insulin and cyclic-adenosine monophosphate response element binding protein (CREB)/brain-derived neurotrophic factor (BDNF) pathways benefited from the regulation of gut microbiota and the promotion of short-chain fatty acid (SCFA) producers such as Romboutsia. Furthermore, this study demonstrated that hesperetin supplementation counteracted the upregulation of β-site amyloid precursor protein cleaving enzyme 1 (BACE1), a pathological factor of Alzheimer's disease (AD) that was induced by metformin. Our findings reveal that hesperetin can be used in supplementary treatment for cognitive impairment associated with diabetes.

Chronic β3 adrenergic agonist treatment improves neurovascular coupling responses, attenuates blood-brain barrier leakage and neuroinflammation, and enhances cognition in aged mice

Microvascular endothelial dysfunction, characterized by impaired neurovascular coupling, reduced glucose uptake, blood-brain barrier disruption, and microvascular rarefaction, plays a critical role in the pathogenesis of age-related vascular cognitive impairment (VCI). Emerging evidence points to non-cell autonomous mechanisms mediated by adverse circulating milieu (an increased ratio of pro-geronic to anti-geronic circulating factors) in the pathogenesis of endothelial dysfunction leading to impaired cerebral blood flow and cognitive decline in the aging population. In particular, age-related adipose dysfunction contributes, at least in part, to an unfavorable systemic milieu characterized by chronic hyperglycemia, hyperinsulinemia, dyslipidemia, and altered adipokine profile, which together contribute to microvascular endothelial dysfunction. Hence, in the present study, we aimed to test whether thermogenic stimulation, an intervention known to improve adipose and systemic metabolism by increasing cellular energy expenditure, could mitigate brain endothelial dysfunction and improve cognition in the aging population. Eighteen-month-old C57BL/6J mice were treated with saline or β3-adrenergic agonist (CL 316, 243, CL) for 6 weeks followed by functional analysis to assess endothelial function and cognition. CL treatment improved neurovascular coupling responses and rescued brain glucose uptake in aged animals. In addition, CL treatment also attenuated blood-brain barrier leakage and associated neuroinflammation in the cortex and increased microvascular density in the hippocampus of aged mice. More importantly, these beneficial changes in microvascular function translated to improved cognitive performance in aged mice. Our results suggest that β3-adrenergic agonist treatment improves multiple aspects of cerebromicrovascular function and can be potentially repurposed for treating age-associated cognitive decline.

Metformin's Effects on Cognitive Function from a Biovariance Perspective: A Narrative Review

This study examines the effects of metformin on brain functions focusing on the variability of the results reported in the literature. While some studies suggest that metformin may have neuroprotective effects in diabetic patients, others report an insignificant impact of metformin on cognitive function, or even a negative effect. We propose that this inconsistency may be due to intrinsic cellular-level variability among individuals, which we term "biovariance". Biovariance persists even in demographically homogeneous samples due to complex and stochastic biological processes. Additionally, the complex metabolic actions of metformin, including its influence on neuroenergetics and neuronal survival, may produce different effects depending on individual metabolic characteristics.

Dipeptidyl Peptidase 4 Inhibitors vs Metformin for New-onset Dementia: A Propensity Score-matched Cohort Study

BACKGROUND

Hypoglycemic pharmacotherapy interventions for alleviating the risk of dementia remain controversial, particularly regarding dipeptidyl peptidase 4 (DPP4) inhibitors vs metformin. Our objective was to investigate whether the initiation of DPP4 inhibitors, as opposed to metformin, was linked to a reduced risk of dementia.

METHODS

We included individuals with type 2 diabetes over 40 years old who were new users of DPP4 inhibitors or metformin in the Chinese Renal Disease Data System database between 2009 and 2020. The study employed Kaplan-Meier and Cox regression for survival analysis and the Fine and Gray model for the competing risk of death.

RESULTS

Following a 1:1 propensity score matching, the analysis included 3626 DPP4 inhibitor new users and an equal number of metformin new users. After adjusting for potential confounders, the utilization of DPP4 inhibitors was associated with a decreased risk of all-cause dementia compared to metformin [hazard ratio (HR) 0.63, 95% confidence interval (CI) 0.45-0.89]. Subgroup analysis revealed that the utilization of DPP4 inhibitors was associated with a reduced incidence of dementia in individuals who initiated drug therapy at the age of 60 years or older (HR 0.69, 95% CI 0.48-0.98), those without baseline macrovascular complications (HR 0.62, 95% CI 0.41-0.96), and those without baseline microvascular complications (HR 0.67, 95% CI 0.47-0.98).

CONCLUSION

In this real-world study, we found that DPP4 inhibitors presented an association with a lower risk of dementia in individuals with type 2 diabetes than metformin, particularly in older people and those without diabetes-related comorbidities.

Neuroprotective effects of traditional Chinese medicine Naofucong on diabetic cognitive impairment: Mechanisms involving insulin-degrading enzyme-mediated degradation of Amyloid-β and inhibition of ERK/JNK/p38 MAPK signaling pathway

The increasing prevalence of diabetes and its related cognitive impairments is a significant public health concern. With limited clinical treatment options and an incomplete understanding of the underlying mechanisms, traditional Chinese medicine (TCM) Naofucong is proposed as a potential neuroprotective agent against diabetic cognitive impairment (DCI). This study aims to investigate the therapeutic mechanisms of Naofucong in DCI. We hypothesize that Naofucong may improve cognitive function in diabetic rats by modulating the extracellular regulated protein kinases (ERK)/c-Jun N-terminal kinase (JNK)/p38 mitogen-activated protein kinases (MAPK) signaling pathway, enhancing insulin-degrading enzyme (IDE) expression, reducing amyloid-beta (Aβ) deposition, decreasing phosphorylated Tau (p-Tau) levels, and alleviating oxidative stress. Diabetes was induced in specific-pathogen-free male Sprague-Dawley rats using streptozotocin, and the rats were treated with oral Naofucong for 12 weeks. We assessed cognitive function and measured neuronal damage, oxidative stress injury, and the expression levels of IDE, Aβ, amyloid precursor protein (APP), p-Tau, and components of the ERK/JNK/p38 MAPK pathway. Diabetic rats showed significant declines in cognitive function, neuronal damage, oxidative stress, low IDE expression, Aβ accumulation, high APP expression, abnormal Tau phosphorylation, and overactivation of the ERK/JNK/p38 MAPK pathway. Naofucong treatment significantly reversed these symptoms. Our findings suggest that Naofucong improves cognitive impairment in diabetic rats by inhibiting the ERK/JNK/p38 MAPK pathway, upregulating IDE, reducing Aβ deposition, suppressing APP and p-Tau expression, and alleviating neuronal damage and oxidative stress. This research provides a reference for the clinical prevention and treatment of DCI using TCM Naofucong.

A Narrative Review on Cognitive Impairment in Type 2 Diabetes: Global Trends and Diagnostic Approaches

Diabetes is a chronic disease that affects many people, with both its incidence and prevalence rising globally. Diabetes can lead to various complications, among which cognitive impairment in diabetic patients significantly impacts their daily life and blood glucose management, complicating treatment and worsening prognosis. Therefore, the early diagnosis and treatment of cognitive impairment are essential to ensure the health of diabetic patients. However, there is currently no widely accepted and effective method for the early diagnosis of diabetes-related cognitive impairment. This review aims to summarize potential screening and diagnostic methods, as well as biomarkers, for cognitive impairment in diabetes, including retinal structure and function examination, brain imaging, and peripheral blood biomarkers, providing valuable information and support for clinical decision making and future research.

Association of late-life variability in hemoglobin A1C with postmortem neuropathologies

INTRODUCTION

To study the relationship of late-life hemoglobin A1C (A1C) with postmortem neuropathology in older adults with and without diabetes mellitus (DM).

METHODS

A total of 990 participants from five cohort studies of aging and dementia with at least two annually-collected A1C measures, who had autopsy. Neuropathologic evaluations documented cerebrovascular disease, Alzheimer's disease (AD), and other pathologies. To evaluate the association of A1C mean and variability (standard deviation [SD]) with neuropathology, we used a series of adjusted regression models.

RESULTS

Participants (mean age at death = 90.8 years; education = 15.8 years; 76% women) had six A1C measurements on average. Mean A1C was associated with greater odds of macroinfarcts (estimate = 0.14; p = 0.04) and subcortical infarcts (estimate = 0.16; p = 0.02). A1C variability was not associated with cerebrovascular pathology. A1C mean and variability were inversely associated with AD pathology.

DISCUSSION

The A1C average over time was associated with infarcts, and the A1C average and variability were inversely associated with AD pathology. Future studies should explore the underlying mechanisms linking A1C to dementia-related neuropathologies.

HIGHLIGHTS

Hemoglobin A1C (A1C), a measure of peripheral insulin resistance, is used to assess glycemic control. Higher A1C mean was associated with greater odds of macroscopic subcortical infarcts. A1C variability was not associated with cerebrovascular pathology. Both A1C mean and variability had inverse associations with AD pathology. None of the associations varied by diabetes mellitus status.

Associations of Mid- and Late-Life Fasting Blood Glucose Levels With Dementia Risk Among Patients With Diabetes: Framingham Heart Study

BACKGROUND

Diabetes is an established risk factor for dementia. However, the association has been less consistent at the population level and may vary over the lifespan. The impacts may be influenced by glucose fluctuation over lifetime.

METHODS

We used data from the Framingham Offspring cohort to evaluate the dementia risk associated with fasting blood glucose (FBG) across age ranges. Cox proportional hazards regression models were fitted to investigate the association of diabetes status at each examination with dementia risk, and the associations between FBG levels and dementia across age spans. Group-based trajectory models were used to create FBG trajectories from mid to late-life for comparison.

RESULTS

Higher FBG level at midlife was not associated with an increased risk of dementia. For participants with diabetes, higher FBG at age 60 and 70 years was associated with subsequent dementia (HR: 1.72, 95% CI: 1.07-2.75; HR: 1.91, 95% CI: 1.24-2.91). Diabetic participants with first midlife increasing and then late-life declining patterns of FBG were at greater increased risk of dementia compared to participant without diabetes. (HR: 2.00, 95% CI: 1.04-3.85).

CONCLUSION

The relationship between FBG and dementia risk was heterogeneous across the adult age range. Diabetes at midlife is a risk factor for dementia, but high glucose levels at 60-70 years followed by a decline suggests that less controlled diabetes during high age risk for dementia onset may represent another prodromal risk factor and presymptomatic metabolic indicator of dementia.

The Mechanism and Treatment of Cognitive Dysfunction in Diabetes: A Review

Diabetes mellitus (DM) is one of the fastest growing diseases in terms of global incidence and seriously affects cognitive function. The incidence rate of cognitive dysfunction is up to 13% in diabetes patients aged 65-74 years and reaches 24% in those aged >75 years. The mechanisms and treatments of cognitive dysfunction associated with diabetes mellitus are complicated and varied. Previous studies suggest that hyperglycemia mainly contributes to cognitive dysfunction through mechanisms involving inflammation, autophagy, the microbial-gut-brain axis, brain-derived neurotrophic factors, and insulin resistance. Antidiabetic drugs such as metformin, liraglutide, and empagliflozin and other drugs such as fingolimod and melatonin can alleviate diabetes-induced cognitive dysfunction. Self-management, intermittent fasting, and repetitive transverse magnetic stimulation can also ameliorate cognitive impairment. In this review, we discuss the mechanisms linking diabetes mellitus with cognitive dysfunction and propose a potential treatment for cognitive decline associated with diabetes mellitus.

The cumulative impact of type 2 diabetes and obstructive sleep apnoea on cardiovascular, liver, diabetes-related and cancer outcomes

AIM

A bidirectional relationship exists between obstructive sleep apnoea (OSA) and type 2 diabetes (T2D). We aimed to examine the cumulative impact of having both OSA and T2D on patient outcomes, relative to having either condition alone.

MATERIALS AND METHODS

Using TriNetX, a global federated research network (n = 128 million), we undertook two retrospective cohort studies, using time-to-event analysis. Analysis 1 compared OSA with T2D versus OSA alone; analysis 2 compared T2D with OSA versus T2D alone. Propensity score matching using greedy nearest neighbour (calliper 0.1) balanced the cohorts (1:1) for significant covariates. Primary outcomes were cardiovascular, liver, diabetes-related (microvascular) and cancer events over 1-5 years.

RESULTS

Analysis 1 (n = 179 688): A codiagnosis of T2D/OSA significantly increased risk of all-cause mortality (hazard ratio [HR] 1.52; confidence interval [CI]: 1.48, 1.57), dementia (HR 1.19; CI: 1.12, 1.26), liver (HR 2.20; CI: 1.77, 2.73), pancreatic (HR 1.62; CI: 1.35, 1.93), colon, renal and endometrial cancers; all cardiovascular, microvascular and liver related outcomes versus OSA alone over 1-5 5 years following OSA diagnosis. Analysis 2 (n = 240 094): A codiagnosis of OSA/T2D significantly increased the risk of peripheral (HR 1.39; CI: 1.36, 1.43) and autonomic (HR 1.63; CI: 1.51, 1.75) neuropathy; retinopathy (HR 1.13; CI: 1.09, 1.18), CKD (HR 1.21; CI: 1.18, 1.23); all cardiovascular and liver outcomes; all-cause mortality and several obesity related cancers versus T2D alone.

CONCLUSIONS

T2D significantly potentiates risk of cardiovascular, malignancy and liver-related outcomes in individuals with OSA. OSA, in individuals with T2D, significantly potentiates risk of cardiovascular disease, malignancy, death and several microvascular complications (retinopathy, CKD, peripheral/autonomic neuropathy).

Causal association between insulin sensitivity index and Alzheimer's disease

Evidence from observational and Mendelian randomization (MR) studies suggested that insulin resistance (IR) was associated with Alzheimer's disease (AD). However, the causal effects of different indicators of IR on AD remain inconsistent. Here, we aim to assess the causal association between the insulin sensitivity index (ISI), a measure of post-prandial IR, and the risk of AD. We first conducted primary and secondary univariable MR analyses. We selected 8 independent genome-wide significant (p < 5E-08, primary analyses) and 61 suggestive (p < 1E-05, secondary analyses) ISI genetic variants from large-scale genome-wide association studies (GWAS; N = 53 657), respectively, and extracted their corresponding GWAS summary statistics from AD GWAS, including IGAP2019 (N = 63 926) and FinnGen_G6_AD_WIDE (N = 412 181). We selected five univariable MR methods and used heterogeneity, horizontal pleiotropy test, and leave-one-out sensitivity analysis to confirm the stability of MR estimates. Finally, we conducted a meta-analysis to combine MR estimates from two non-overlapping AD GWAS datasets. We further performed multivariable MR (MVMR) to assess the potential mediating role of type 2 diabetes (T2D) on the association between ISI and AD using two MVMR methods. In univariable MR, utilizing 8 genetic variants in primary analyses, we found a significant causal association of genetically increased ISI with decreased risk of AD (OR = 0.79, 95% CI: 0.68-0.92, p = 0.003). Utilizing 61 genetic variants in secondary analyses, we found consistent findings of a causal effect of genetically increased ISI on the decreased risk of AD (OR = 0.89, 95% CI: 0.82-0.96, p = 0.003). Heterogeneity, horizontal pleiotropy test, and leave-one-out sensitivity analysis ensured the reliability of the MR estimates. In MVMR, we found no causal relationship between ISI and AD after adjusting for T2D (p > 0.05). We provide genetic evidence that increased ISI is significantly and causally associated with reduced risk of AD, which is mediated by T2D. These findings may inform prevention strategies directed toward IR-associated T2D and AD.

High Rosmarinic Acid Content Melissa officinalis L. Phytocomplex Modulates Microglia Neuroinflammation Induced by High Glucose

Diabetic patients experience hyperglycemia, which can affect multiple organs, including brain function, leading to disabling neurological complications. Hyperglycemia plays a key role in promoting neuroinflammation, the most common complication in diabetic individuals, through the activation of microglia. Attenuating hyperglycemia-related neuroinflammation in microglia may reduce diabetes-associated neurological comorbidities. Natural remedies containing phenolic compounds have shown efficacy in mitigating microglia-mediated neuroinflammation. The aim of this study was to investigate the potential of a Melissa officinalis L. (MO) phytocomplex, obtained from plant cell cultures and enriched in its main polyphenolic constituent, rosmarinic acid (RA), in attenuating hyperglycemia-induced neuroinflammation in microglia. A time-course morphological analysis of BV2 microglial cells exposed to high glucose (HG) levels showed a shift towards a proinflammatory phenotype, peaking after 48 h, which was reversed by pretreatment with MO. Biochemical assays revealed increased expression of the microglial marker CD11b (187%), activation of the NF-κB pathway (179%), expression of iNOS (225%), enhanced phosphorylation of ERK1/2 (180%), and increased expression of the proinflammatory cytokine IL-6 (173%). Pretreatment with MO prevented the aberrant expression of these proinflammatory mediators and restored SIRT1 levels. Exposure of neuronal SH-SY5Y cells to the conditioned medium from HG-exposed microglia significantly reduced cell viability. MO counteracted this effect, exhibiting neuroprotective activity. RA showed efficacy comparable to that of MO. In conclusion, MO and RA attenuated microglia-mediated oxidative imbalance and neuroinflammation under HG exposure by inhibiting the morphological shift toward a proinflammatory phenotype induced by HG and abrogating the subsequent activation of the downstream ERK1/2-NF-κB-iNOS pathway.

Cognitive dysfunction in diabetes - the 'forgotten' diabetes complication: a narrative review

BACKGROUND

In addition to peripheral neuropathy of various kinds, diabetes can also cause central neuropathy, which among other things can manifest itself as premature cognitive dysfunction, often linked to vascular dysfunction. Although the link between diabetes and cognitive dysfunction was discovered more than 100 years ago and has important clinical implications, this diabetes complication remains relatively unknown. Recent years have seen research that has clarified cerebral insulin resistance and defective insulin signaling as examples of pathogenic factors behind this cognitive impairment in diabetes.

METHOD

We provide a narrative review of select and contemporary publications with relevance for the interface between diabetes/prediabetes and cognitive function.

RESULTS

Recently published studies show that physical activity can reverse insulin resistance in the brain as well as cognitive impairment and pathological appetite regulation. Pharmacological interventions with, for example, nasal insulin, GLP-1 receptor agonists, SGLT-2 inhibitors, or PPAR-γ agonists have also shown promising results.

CONCLUSION

Optimization of lifestyle factors (e.g. physical activity), as well as several pharmaceutical agents already in clinical use against diabetes, have shown promising results in improving cognitive function in diabetic patients. An important task for primary health care, where most patients with type 2 diabetes are diagnosed, treated, and followed, is to increase awareness and early detection of cognitive dysfunction in these patients for optimizing risk factor control.

Association Between Weight-Adjusted Waist Index and Cognitive Function in Older Adults Without Diabetes: A Cross-Sectional Study

Background

This study investigates the correlation between the weight-adjusted waist index (WWI) and cognitive performance in the senior American population, focusing on those without diabetes from 2011 to 2014.

Methods

We analyzed data from the 2011-2012 and 2013-2014 National Health and Nutrition Examination Surveys (NHANES), focusing on non-diabetic participants aged 60 and older who completed cognitive tests: Establish a Registry for Alzheimer's disease (CERAD), the Animal Fluency test (AFT), and Digit Symbol Substitution test (DSST). WWI was calculated using waist circumference divided by the square root of body weight. We employed linear univariate and multivariate analyses, along with curve fitting, we conducted subgroup and interaction analyses to elucidate the relationships under investigation.

Results

The study incorporated a cohort of 1649 participants aged 60 years and older, each with a complete set of data, enabling a thorough analysis. After adjusting for confounding factors, significant negative correlations were found between WWI and both CERAD (β: -0.48; 95% CI: -0.92 to -0.05; P=0.03) and DSST (β: -1.15; 95% CI: -2.09 to -0.21; P=0.017) scores, suggesting a link to cognitive decline. No association was found with AFT scores. The relationship between WWI and DSST was found to be nonlinear (P for non-linearity=0.022). Additionally, the association between WWI and CERAD was also observed (P for non-linearity=0.042). However, linear relationships were observed between WWI and AFT (P for non-linearity=0.418). The subgroup analysis was overall stable.

Conclusion

Our cross-sectional study indicates a strong link between a high WWI and reduced cognitive function in non-diabetic older Americans, as shown by CERAD and DSST scores. Attaining an optimal WWI may be vital for cognitive decline, highlighting its role in a potential preventative approach.

Clinical Trial Registry Number and Website Where It Was Obtained

The study design and data are publicly accessible at www.cdc.gov/nchs/nhanes/.

Menstrual cycle characteristics across the reproductive lifespan and cognitive function in midlife women

BACKGROUND

Menstrual cycle characteristics are potential indicators of hormonal exposures and may also signal cardiovascular disease risk factors, both of which are relevant to cognitive health. However, there is scarce epidemiological evidence on the association between cycle characteristics and cognitive function.

OBJECTIVE

We studied the associations of menstrual cycle characteristics at 3 stages of a woman's reproductive lifespan with cognitive function in midlife.

STUDY DESIGN

We studied participants from the Nurses' Health Study II, an ongoing longitudinal cohort of female nurses initially enrolled in 1989. Exposures were cycle regularity at 14 to 17 and 18 to 22 years, and cycle length (the interval between 2 consecutive cycles) at 18 to 22 years (all retrospectively reported at enrollment), and current cycle regularity and length at 29 to 46 years (reported in 1993). Outcomes were composite z scores measuring psychomotor speed/attention and learning/working memory obtained with 1 self-administered Cogstate Brief Battery assessment, measured among a subset of participants in 2014 to 2022. We included 19,904 participants with data on at least 1 menstrual cycle characteristic and a cognitive assessment. We estimated mean differences (β, 95% confidence intervals) using linear regression models adjusted for age at cognitive assessment, race and ethnicity, participants' education, wave of cognitive assessment, parental education and occupation, neighborhood socioeconomic status, age at menarche, adiposity, oral contraceptive use, and lifestyle factors (smoking, alcohol intake, physical activity, diet quality).

RESULTS

In the analytical sample, the mean (standard deviation [SD]) age at cognitive assessment was 62.0 (4.9) years. Women with irregular cycles at 29 to 46 years scored lower in learning/working memory (β, -0.05 SD; 95% confidence interval, -0.08 to -0.01) than those with very regular cycles. We did not observe associations for cycle regularity at 14 to 17 or 18 to 22 years. Women with cycle length ≤25 days at 18 to 22 years scored lower in learning/working memory in later life (β, -0.05 SD; -0.09 to -0.02) than those with cycles 26 to 31 days. We did not observe associations of cycle length at 29 to 46 years with later cognitive function. In a secondary analysis, women whose cycles were regular at 14 to 17 or 18 to 22 years but became irregular by 29 to 46 years also had lower learning/working memory scores, compared to women whose cycles remained regular across time points.

CONCLUSION

In this large longitudinal study, cycles ≤25 days at 18 to 22 years and irregular cycles at 29 to 46 years were associated with lower performance in learning/working memory. Future studies in other populations should confirm our findings and investigate the biological processes underlying these associations.

Association between use of sodium-glucose co-transporter-2 inhibitor and the risk of incident dementia: a population-based cohort study

OBJECTIVES

To assess the association between sodium-glucose co-transporter-2 inhibitor (SGLT-2i) use and the risk of incident dementia compared with dipeptidyl peptidase-4 inhibitors (DPP-4i) use among individuals with type 2 diabetes.

DESIGN

A population-based retrospective cohort study.

SETTING

The Clinical Practice Research Datalink (CPRD) Aurum database from the UK.

PARTICIPANTS

Individuals with type 2 diabetes, aged 40 years or older, newly prescribed SGLT-2i or DPP-4i on or after 2013-2021, registered in the CPRD Aurum database.

MAIN OUTCOME MEASURE

The primary outcome was incident dementia, and the secondary outcome was incident mild cognitive impairment (MCI). Cox proportional hazard models were used to estimate the HR and corresponding 95% CI for the primary and secondary outcomes. Propensity score fine stratification weights were used to adjust for confounding.

RESULTS

Among a cohort of 118 006 individuals, the incident rate (IR) of dementia was 0.56/1000 person-years over a median follow-up period of 1.54 years among SGLT-2i users compared with 2.67/1000 person-years in DPP-4i users, over a median follow-up period of 1.79 years. The adjusted HR for SGLT-2i use compared with DPP-4i use for dementia was 0.78 (95% CI 0.55 to 1.12), while for MCI was 0.86 (95% CI 0.80 to 0.92). The age-specific stratified analysis demonstrated the adjusted HR for SGLT-2i use compared with DPP-4i use for the risk of incident dementia among elderly, aged ≥65 years, was 0.50 (95% CI 0.31 to 0.80).

CONCLUSION

Primary findings did not yield conclusive evidence to infer an association between SGLT-2i use and the risk of incident dementia.

Type 2 diabetes mellitus: A cross-sectional analysis of glycemic controls and brain health outcomes

In this cross-sectional analysis, we explored how fluctuations in glycemic levels impact executive functions and psychosocial outcomes in patients with type 2 diabetes mellitus (T2DM). The goal was to understand the relationship between glycemic control and both neuropsychological and psychosocial health. We stratified participants into well-controlled and poorly controlled groups based on glycated hemoglobin (HbA1c) levels and variability, including a healthy control group for comparison. The study consisted of neuropsychological tests and psychosocial assessments. Results indicated that the poorly controlled T2DM group experienced significant executive dysfunction and scored lower on the Tower of London, Wisconsin Card Sorting, and Digit Span Tests, reflecting a broader impact on quality of life and resilience. These findings support the importance of maintaining stable glycemic levels for better executive and psychosocial outcomes and highlight the need for regular neuropsychological and psychosocial assessments in diabetes care.

Machine learning identifies routine blood tests as accurate predictive measures of pollution-dependent poor cognitive function

Background

Several modifiable risk factors for dementia and related neurodegenerative diseases have been identified including education level, socio-economic status, and environmental exposures - however, how these population-level risks relate to individual risk remains elusive. To address this, we assess over 450 potential risk factors in one deeply clinically and demographically phenotyped cohort using random forest classifiers to determine predictive markers of poor cognitive function. This study aims to understand early risk factors for dementia by identifying predictors of poor cognitive performance amongst a comprehensive battery of imaging, blood, atmospheric pollutant and socio-economic measures.

Methods

Random forest modelling was used to determine significant predictors of poor cognitive performance in a cohort of 324 individuals (age 61.6 ± 4.8 years; 150 males, 174 females) without extant neurological disease. 457 features were assessed including brain imaging measures of volume and iron deposition, blood measures of anaemia, inflammation, and heavy metal levels, social deprivation indicators and atmospheric pollution exposure.

Results

Routinely assessed markers of anaemia including mean corpuscular haemoglobin concentration were identified as robust predictors of poor general cognition, where both extremes (low and high) were associated with poor cognitive performance. The strongest, most consistent predictors of poor cognitive performance were environmental measures of atmospheric pollution, in particular, lead, carbon monoxide, and particulate matter. Feature analysis demonstrated a significant negative relationship between low mean corpuscular haemoglobin concentration and high levels of atmospheric pollutants highlighting the potential of routinely assessed blood tests as a predictive measure of pollution-dependent cognitive functioning, at an individual level.

Conclusions

Taken together, these data demonstrate how routine, inexpensive medical testing and local authority initiatives could help to identify and protect at-risk individuals. These findings highlight the potential to identify individuals for targeted, cost effective medical and social interventions to improve population cognitive health.

Lifetime history of gestational diabetes and cognitive function in parous women in midlife

AIMS/HYPOTHESIS

We aimed to determine whether a history of gestational diabetes mellitus (GDM) is associated with cognitive function in midlife.

METHODS

We conducted a secondary data analysis of the prospective Nurses' Health Study II. From 1989 to 2001, and then in 2009, participants reported their history of GDM. A subset participated in a cognition sub-study in 2014-2019 (wave 1) or 2018-2022 (wave 2). We included 15,906 parous participants (≥1 birth at ≥18 years) who completed a cognitive assessment and were free of CVD, cancer and diabetes before their first birth. The primary exposure was a history of GDM. Additionally, we studied exposure to GDM and subsequent type 2 diabetes mellitus (neither GDM nor type 2 diabetes, GDM only, type 2 diabetes only or GDM followed by type 2 diabetes) and conducted mediation analysis by type 2 diabetes. The outcomes were composite z scores measuring psychomotor speed/attention, learning/working memory and global cognition obtained with the Cogstate brief battery. Mean differences (β and 95% CI) in cognitive function by GDM were estimated using linear regression.

RESULTS

The 15,906 participants were a mean of 62.0 years (SD 4.9) at cognitive assessment, and 4.7% (n=749) had a history of GDM. In models adjusted for age at cognitive assessment, race and ethnicity, education, wave of enrolment in the cognition sub-study, socioeconomic status and pre-pregnancy characteristics, women with a history of GDM had lower performance in psychomotor speed/attention (β -0.08; 95% CI -0.14, -0.01) and global cognition (β -0.06; 95% CI -0.11, -0.01) than those without a history of GDM. The lower cognitive performance in women with GDM was only partially explained by the development of type 2 diabetes.

CONCLUSIONS/INTERPRETATION

Women with a history of GDM had poorer cognition than those without GDM. If replicated, our findings support future research on early risk modification strategies for women with a history of GDM as a potential avenue to decrease their risk of cognitive impairment.

Diabetes and cardiovascular disease in older adults

An aging population combined with a rapidly increasing prevalence of diabetes foreshadows a global epidemic of cardiovascular and kidney disease that threatens to halt improvements in life and health-span and will have particularly severe consequences in older adults. The management of diabetes has been transformed with the recent development of newer anti-hyperglycemic agents that have demonstrated superior efficacy. However, the utility of these drugs extends beyond glycemic control to benefits for managing obesity, cardiovascular disease (CVD), chronic kidney disease, and heart failure. Numerous cardiovascular and kidney outcomes trials of these drugs have played an instrumental role in shaping current guidelines for the management of diabetes and CVD. Older adults with diabetes are diverse in terms of their comorbidities, diabetic complications, and cognitive and functional status. Therefore, there is an unmet need for personalized management of diabetes and CVD in this population. In this review, we provide an overview of the epidemiological burden and management of diabetes and CVD in older adults. We then focus on randomized cardiovascular and kidney outcome trials with anti-hyperglycemic agents to propose an evidence-based approach to the management of diabetes in older adults with high risk of cardiovascular and kidney disease.

The role of the neurovascular unit in vascular cognitive impairment: Current evidence and future perspectives

Vascular cognitive impairment (VCI) is a progressive cognitive impairment caused by cerebrovascular disease or vascular risk factors. It is the second most common type of cognitive impairment after Alzheimer's disease. The pathogenesis of VCI is complex, and neurovascular unit destruction is one of its important mechanisms. The neurovascular unit (NVU) is responsible for combining blood flow with brain activity and includes endothelial cells, pericytes, astrocytes and many regulatory nerve terminals. The concept of an NVU emphasizes that interactions between different types of cells are essential for maintaining brain homeostasis. A stable NVU is the basis of normal brain function. Therefore, understanding the structure and function of the neurovascular unit and its role in VCI development is crucial for gaining insights into its pathogenesis. This article reviews the structure and function of the neurovascular unit and its contribution to VCI, providing valuable information for early diagnosis and prevention.

Optimizing infant neuroimaging methods to understand the neurodevelopmental impacts of early nutrition and feeding

There is strong evidence proper nutrition is imperative for healthy infant neurodevelopment, providing the neural foundations for later cognition and behavior. Over the first years of life infants are supported by unique sources of nutrition (e.g., human milk, alternative milk sources). It is during this time that the brain undergoes its most drastic changes during postnatal development. Past research has examined associations between infant feeding and nutrition and morphological features of the brain, yet there remains a paucity of information on functional characteristics of neural activity during feeding. Within this article, we discuss how neuroimaging modalities can be optimized for researching the impacts of infant feeding and nutrition on brain function. We review past research utilizing EEG and fNIRS and describe our efforts to further develop neuroimaging approaches that allow for measurement of brain activity during active feeding with greater spatial resolution (e.g., fMRI and OPM-MEG). We also discuss current challenges, as well as the scientific and logistical limitations of each method. Once protocols have been optimized, these methods will provide the requisite insight into the underlying mechanisms of nutritional and feeding impacts on neurodevelopment, providing the missing piece in the field's efforts to understand this essential and ubiquitous part of early life.

Review of Associations of Diabetes and Insulin Resistance With Brain Health in Three Harmonised Cohort Studies of Ageing and Dementia

Diabetes increases the risk of dementia, and insulin resistance (IR) has emerged as a potential unifying feature. Here, we review published findings over the past 2 decades on the relation of diabetes and IR to brain health, including those related to cognition and neuropathology, in the Religious Orders Study, the Rush Memory and Aging Project, and the Minority Aging Research Study (ROS/MAP/MARS), three harmonised cohort studies of ageing and dementia at the Rush Alzheimer's Disease Center (RADC). A wide range of participant data, including information on medical conditions such as diabetes and neuropsychological tests, as well as other clinical and laboratory-based data collected annually. Neuropathology data are collected in participants who agree to autopsy at death. Recent studies have measured additional peripheral and brain IR data, including multi-omics. This review summarises findings from the RADC cohort studies that investigate the relation of diabetes and IR in older adults to cognition, neuropathology, omics in dementia, and other brain health measures. Examining the risk of clinically diagnosed dementia in older adults, our study found a 65% increased risk of Alzheimer's disease (AD) dementia in individuals with diabetes compared with those without. Regarding cognitive function, we have consistently observed associations of diabetes, as well as both peripheral and brain IR, with worse and declining performance in global cognition and specific cognitive domains, particularly semantic memory and perceptual speed. Studies utilising neuropathological data showed associations of diabetes and peripheral IR with brain infarcts, while brain IR measures, notably alpha serine/threonine-protein kinase1 (AKT1), were associated with both brain infarcts and AD pathology. Multi-omics studies suggested shared causal genes and pathways between diabetes and dementia. Recent epigenetic studies have revealed associations between IR and AD risk, along with distinct 5-hydroxymethylcytosine signatures in diabetes-associated AD. Furthermore, our studies have utilised other available data to investigate the impact of diabetes on neurological outcomes other than cognition and reported worsening of parkinsonian-like signs in diabetes. Recent studies have also explored risk factors for diabetes and have reported associations between lower literacy and decision-making abilities with elevated haemoglobin A1C levels, a peripheral IR measure. Overall, our findings, as summarised in this review, illustrate a range of mechanistic and other insights into the complex relationship of diabetes and IR with brain health. These findings may have important implications for future research on the ageing brain, including the prevention of cognitive decline and dementia in persons at risk for or with diabetes.

13. Older Adults: Standards of Care in Diabetes-2025

The American Diabetes Association (ADA) "Standards of 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, an interprofessional expert committee, 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 and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Metabolic dysfunction and insulin sensitizers in acute and chronic disease

INTRODUCTION

The concept of insulin resistance has been a major topic for more than 5 decades. While there are several treatments that may impact insulin resistance, this pathology is uniquely addressed by mitochondrially directed thiazolidinedione (TZD) insulin sensitizers. Understanding of this mechanism of action and consideration of 'insulin resistance' as a consequence of metabolic inflammation allows a new paradigm for approaching chronic diseases.

AREAS COVERED

We review evolving understanding of the mitochondrial pyruvate carrier (MPC) as a mitochondrial mechanism of action of the TZD insulin sensitizers and discuss how reprogramming of mitochondrial metabolism impacts pleotropic pharmacology in multiple tissues. Additional lines of investigation are proposed.

EXPERT OPINION

A change in paradigm can facilitate rethinking of insulin sensitizers in clinical trials, specifically beyond the treatment of frank type 2 diabetes. There should be broader clinical evaluation of insulin sensitizers in combination with weight loss and lifestyle approaches across diseases/syndromes associated with insulin resistance. Finally, 'connecting all the dots' to unwind the interconnectedness of cell biology involved in the syndromes impacted by metabolic dysfunction and the efficacy of TZD insulin sensitizers may also uncover new molecular targets. New studies should facilitate the discovery and development of novel pharmacologic agents.

Associations between nutritional status and abdominal adiposity with cognitive domains and depressive symptoms in older persons with multimorbidity: Understanding an understudied population

BACKGROUND

Malnutrition is a prevalent issue among older persons and has been linked to adverse outcomes. Limited information exists regarding its connection with cognition and depression in older persons burdened by chronic diseases, experiencing heightened nutritional and psychosocial vulnerability. In this study, we examined the association between nutritional status, cognitive performance, and depressive symptomatology, in a cohort of older persons with multimorbidity.

METHODS

This was a cross-sectional study of 114 pluripathological older persons. Nutritional status was assessed through Mini Nutritional Assessment (MNA), body mass index (BMI) and waist and calf circumferences. Cognition was assessed using Montreal Cognitive Assessment (MoCA) and depressive symptoms were measured with the 15-item Geriatric Depression Scale (GDS-15).

RESULTS

MNA score was positively correlated with the MoCA's visuospatial score (rho=0.262) and, participants with normal nutritional status according to MNA, performed better in orientation (p=0.037) and abstraction (p=0.013) domains. MNA was also associated with depressive symptoms, with odds 8.6 times higher in malnourished participants (AOR 8.6, 95% CI 2.6-28.8, p=0.000). Abdominal obesity, meanwhile, was associated with a decrease of 3.33 points in the overall MoCA score (β -3.33, 95% CI=-5.92; -0.73, p=0.013).

CONCLUSION

In older persons with multimorbidity, abdominal obesity and malnutrition were factors associated with lower global and domain-specific cognitive performance and increased depressive symptomatology.

Olfactory Dysfunction as a Biomarker for Early Diagnosis of Cognitive Impairment in Patients With Type 2 Diabetes: A Systematic Review

Background: Olfactory dysfunction and cognitive impairment (CI) have been associated with Type 2 diabetes (T2DM), but the mechanisms underlying this association are broadly unknown. This systematic review tends to investigate the relationship between the onset of olfactory dysfunction and CI in patients with T2DM and to explore the potential role of olfactory dysfunction as an early diagnosis biomarker of CI. Methods: We conducted a systematic review consulting PubMed and Scopus. The articles considered eligible included patients with T2DM and cognitive and olfactory test. Results: The search identified a total of 145 articles, of which 13 were finally selected. The majority of these studies discovered a correlation between olfactory dysfunction and CI in individuals with T2DM. Additionally, other biomarkers such as functional magnetic resonance imaging demonstrated changes in brain regions associated with the sense of smell in T2DM patients. Conclusions: Olfactory dysfunction could be a biomarker for early diagnosis of CI in T2DM. However, these alterations are highly heterogeneous and more studies that include neuroimaging need to be conducted.

The double life of glucose metabolism: brain health, glycemic homeostasis, and your patients with type 2 diabetes

The maintenance of cognitive function is essential for quality of life and health outcomes in later years. Cognitive impairment, however, remains an undervalued long-term complication of type 2 diabetes by patients and providers alike. The burden of sustained hyperglycemia includes not only cognitive deficits but also the onset and progression of dementia-related conditions, including Alzheimer's disease (AD). Recent research has shown that the brain maintains an independent glucose "microsystem"-evolved to ensure the availability of fuel for brain neurons without interruption by transient hypoglycemia. When this milieu is perturbed, brain hyperglycemia, brain glucotoxicity, and brain insulin resistance can ensue and interfere with insulin signaling, a key pathway to cognitive function and neuronal integrity. This newly understood brain homeostatic system operates semi-autonomously from the systemic glucoregulatory apparatus. Large-scale clinical studies have shown that systemic dysglycemia is also strongly associated with poorer cognitive outcomes, which can be mitigated through appropriate clinical management of plasma glucose levels. Moreover, these studies demonstrated that glucose-lowering agents are not equally effective at preventing cognitive dysfunction. Glucagon-like peptide-1 (GLP-1) receptor analogs and sodium glucose cotransporter 2 inhibitors (SGLT2is) appear to afford the greatest protection; metformin and dipeptidyl peptidase 4 inhibitors (DPP-4is) also significantly improved cognitive outcomes. Sulfonylureas (SUs) and exogenous insulin, on the other hand, do not provide the same protection and may actually worsen cognitive outcomes. In the creation of a treatment plan, comorbid cognitive conditions should be considered. These efficacious treatments create a new gold standard of managing hyperglycemia-one which is consistent with the "complication-centric prescribing" mandates issued in type 2 diabetes treatment guidelines. The increasing longevity enjoyed by our populace places the onus on clinical care to play the "long game" in using targeted treatments for glucose control in patients with, or at risk for, cognitive decline to maintain cognitive wellness later in life. This article reviews critical emerging data for scientists and trialists and translates new enhancements in patient care for practitioners.

Early Detection of Dementia in Populations With Type 2 Diabetes: Predictive Analytics Using Machine Learning Approach

BACKGROUND

The possible association between diabetes mellitus and dementia has raised concerns, given the observed coincidental occurrences.

OBJECTIVE

This study aimed to develop a personalized predictive model, using artificial intelligence, to assess the 5-year and 10-year dementia risk among patients with type 2 diabetes mellitus (T2DM) who are prescribed antidiabetic medications.

METHODS

This retrospective multicenter study used data from the Taipei Medical University Clinical Research Database, which comprises electronic medical records from 3 hospitals in Taiwan. This study applied 8 machine learning algorithms to develop prediction models, including logistic regression, linear discriminant analysis, gradient boosting machine, light gradient boosting machine, AdaBoost, random forest, extreme gradient boosting, and artificial neural network (ANN). These models incorporated a range of variables, encompassing patient characteristics, comorbidities, medication usage, laboratory results, and examination data.

RESULTS

This study involved a cohort of 43,068 patients diagnosed with type 2 diabetes mellitus, which accounted for a total of 1,937,692 visits. For model development and validation, 1,300,829 visits were used, while an additional 636,863 visits were reserved for external testing. The area under the curve of the prediction models range from 0.67 for the logistic regression to 0.98 for the ANNs. Based on the external test results, the model built using the ANN algorithm had the best area under the curve (0.97 for 5-year follow-up period and 0.98 for 10-year follow-up period). Based on the best model (ANN), age, gender, triglyceride, hemoglobin A1c, antidiabetic agents, stroke history, and other long-term medications were the most important predictors.

CONCLUSIONS

We have successfully developed a novel, computer-aided, dementia risk prediction model that can facilitate the clinical diagnosis and management of patients prescribed with antidiabetic medications. However, further investigation is required to assess the model's feasibility and external validity.

Effect of randomised blood pressure lowering treatment and intensive glucose control on dementia and cognitive decline according to baseline cognitive function and other subpopulations of individuals with type 2 diabetes: Results from the ADVANCE trial

Background and aims

Accumulating evidence indicates that reducing high blood pressure (BP) prevents dementia and mild cognitive impairment (MCI). Furthermore, although diabetes is a risk factor for dementia and MCI, there is uncertainty of the effect of intensive glucose control on these endpoints. This study aimed to determine the effects of BP-lowering (vs placebo) and intensive glucose-lowering (vs standard control) treatments according to baseline cognition and other characteristics on dementia and cognitive decline (CD) in people with type 2 diabetes mellitus (T2DM).

Methods

The Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) trial involved 11,140 individuals with T2DM. The effects of BP-lowering and intensive glucose-lowering treatments were explored in subgroups of baseline Mini-Mental State Examination (MMSE), categorised as cognitively normal (scores ≥28) and cognitive impairment (scores <28). The primary outcome was a composite of dementia/CD that accounted for the competing risk of death. Multinomial regression models, adjusted for common cardiovascular risk factors, were used to estimate odds ratios (OR) with 95 % confidence intervals (CI) of the effects of the treatments on dementia/CD. Homogeneity of effects by subgroups were evaluated using interaction terms in the models. A two-sided p value <0.05 was regarded as statistically significant.

Results

BP-lowering treatment (vs. placebo) was associated with a lower odds of dementia/CD in participants with cognitive impairment (OR 0.76, 95 % CI (0.59-0.99)) but not in those cognitively normal (OR 1.05, 95 % CI (0.92-1.21); p for interaction 0.03). Those with a history of cardio-renal-metabolic syndrome did not experience a benefit of active BP lowering treatment compared with placebo on dementia/CD. There were no further subgroup effects of BP-lowering treatment. The effect of intensive glucose lowering (vs standard control) on the odds of dementia/CD did not vary by baseline cognition subgroup. However, it did vary by level of blood glucose at baseline (<7.9 mmol/L OR 1.12, 95 % CI (0.96-1.30) vs ≥ 7.9 mmol/L 0.87 (0.75-1.00); p for interaction 0.02) and duration of T2DM (<10 years OR 0.92 (0.81-1.05) vs ≥10 years 1.16 (0.97-1.38); p for interaction 0.04).

Conclusions

This study suggests greater effects of BP-lowering treatment in those with early loss of cognitive function than in those cognitively normal. There were also differential effects of intensive glucose-lowering on dementia and CD according to levels of blood glucose and duration of diabetes in people with T2DM.

Clinical trial registration

ADVANCE is registered with ClinicalTrials.gov: number NCT00145925.