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

Specification curve analysis to identify heterogeneity in risk factors for dementia: findings from the UK Biobank

BACKGROUND

In 2020, the Lancet Commission identified 12 risk factors as priorities for prevention of dementia, and other studies identified APOE e4/e4 genotype and family history of Alzheimer's disease strongly associated with dementia outcomes; however, it is unclear how robust these relationships are across dementia subtypes and analytic scenarios. Specification curve analysis (SCA) is a new tool to probe how plausible analytical scenarios influence outcomes.

METHODS

We evaluated the heterogeneity of odds ratios for 12 risk factors reported from the Lancet 2020 report and two additional strong associated non-modifiable factors (APOE e4/e4 genotype and family history of Alzheimer's disease) with dementia outcomes across 450,707 UK Biobank participants using SCA with 5357 specifications across dementia subtypes (outcomes) and analytic models (e.g., standard demographic covariates such as age or sex and/or 14 correlated risk factors).

RESULTS

SCA revealed variable dementia risks by subtype and age, with associations for TBI and APOE e4/e4 robust to model specification; in contrast, diabetes showed fluctuating links with dementia subtypes. We found that unattributed dementia participants had similar risk factor profiles to participants with defined subtypes.

CONCLUSIONS

We observed heterogeneity in the risk of dementia, and estimates of risk were influenced by the inclusion of a combination of other modifiable risk factors; non-modifiable demographic factors had a minimal role in analytic heterogeneity. Future studies should report multiple plausible analytic scenarios to test the robustness of their association. Considering these combinations of risk factors could be advantageous for the clinical development and evaluation of novel screening models for different types of dementia.

The relationship between diabetes and the dementia risk: a meta-analysis

BACKGROUND

The link between diabetes and dementia risk is not well understood. This study evaluates the factors linking diabetes to dementia onset, providing guidance for preventing dementia in diabetic patients.

METHODS

This analysis utilized databases such as PubMed, Embase, Web of Science, and the Cochrane Library to review literature from January 31, 2012, to March 5, 2023. Articles were rigorously assessed using specific inclusion and exclusion criteria. The Newcastle-Ottawa Scale (NOS) was used to evaluate the quality of the studies. Data analysis was performed with STATA 15.0.

RESULTS

The study analyzed 15 articles, covering 10,103,868 patients, with 8,821,516 diagnosed with diabetes. The meta-analysis reveals a substantial association between diabetes and an increased risk of dementia [RR: 1.59, 95%CI (1.40-1.80), P < 0.01, I²=96.4%]. A diabetes duration of less than five years is linked to a higher dementia risk [RR: 1.29, 95%CI (1.20-1.39), P < 0.01, I²=92.6%]. Additionally, hypoglycemia significantly raises dementia risk [RR: 1.56, 95%CI (1.13-2.16), P < 0.01, I²=51.5%]. Analyses of blood sugar control, glycated hemoglobin, and fasting blood sugar indicated no significant effects on the onset of dementia.

CONCLUSION

Diabetes notably increases dementia risk, particularly where diabetes duration is under five years or hypoglycemia is present.

REGISTRATION

The research protocol was registered with PROSPERO and assigned the registration number CRD42023394942.

Glycemic control and dementia risk in patients aged above and below 75 years

Background

There is a lack of data about the treatment effect of glycemic control on incident dementia in patients with advanced age.

Methods

In a nationwide Korean cohort of 79,076 diabetic patients 75 years or older and a representative cohort of 74,672 diabetics aged 50 to 74 years, multivariable-adjusted incidence of overt dementia was estimated across yearly-averaged on-treatment fasting blood glucose (FBG) levels.

Results

During 9-year follow-up, overt dementia was noted in 24,710 (31.2%) patients 75 years or older and in 5237 (7.0%) patients aged 50 to 74 years. For dementia risk, J-shaped associations were observed across on-treatment FBG levels (80-99, 100-109, 110-125, 126-139, 140-159, 160-179, and 180-900 mg/dl) in patients 75 years or older (respective incidence: 49.3, 45.7, 45.9, 45.7, 48.5, 51.5, and 57.9 per 1000 person-years) and in those aged 50 to 74 years (respective incidence: 8.9, 8.3, 7.7, 7.6, 8.0, 8.6, and 10.6 per 1000 person-years) with a significant interaction of FBG level and age group (P = 0.001). For all-cause mortality, the J-shaped association curve was left-shifted in patients 75 years or older (respective incidence: 64.9, 59.1, 57.6, 60.4, 64.0, 70.9, and 90.4 per 1000 person-years) relative to that in patients aged 50 to 74 years (respective incidence: 15.7, 13.4, 12.3, 12.2, 13.4, 15.7, and 21.8 per 1000 person-years; P < 0.001 for interaction).

Conclusion

The achieved glycemic level with the lowest risk for dementia and mortality was lower in older patients, and absolute risk increase related to poorly controlled glucose was greater in the elderly compared with younger patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13340-023-00684-4.

Risk of Dementia Among Patients With Diabetes in a Multidisciplinary, Primary Care Management Program

Importance

Although poorly controlled diabetes is associated with a higher incidence of dementia, few studies have examined the association of diabetes management interventions with dementia incidence.

Objective

To examine the association of receiving a multidisciplinary diabetes management program (the Risk Assessment and Management Program-Diabetes Mellitus [RAMP-DM]) that enables better glycemic control with subsequent risk of dementia incidence and the association of dementia with glycemic control.

Design, Setting, and Participants

This territory-wide, retrospective, matched cohort study with more than 8 years of follow-up was conducted using electronic health care records from all the patients who used public health care services in Hong Kong from 2011 to 2019. Eligible participants included all patients with type 2 diabetes (T2D) who were managed in primary care settings. Patients who received RAMP-DM were matched in a 1:1 ratio with patients who received usual care only. Data analysis occurred from April 2023 to July 2023.

Exposures

Diagnosis of T2D, hemoglobin A1C (HbA1C) level, and attendance at a general outpatient clinic or family medicine clinic. Patients received either RAMP-DM or usual care.

Main Outcomes and Measures

Incidence of all-cause dementia and subtypes of dementia were compared between the RAMP-DM and usual care participants using a Cox proportional hazard model with other baseline characteristics, biomarkers, and medication history adjusted. HbA1C levels were measured as a secondary outcome.

Results

Among the 55 618 matched participants (mean [SD] age, 62.28 [11.90] years; 28 561 female [51.4%]; 27 057 male [48.6%]), including the 27 809 patients in the RAMP-DM group and 27 809 patients in the usual care group, patients had been diagnosed with T2D for a mean (SD) of 5.90 (4.20) years. During a median (IQR) follow-up period of 8.4 (6.8-8.8) years, 1938 patients in the RAMP-DM group (6.97%) and 2728 patients in the usual care group (9.81%) received a diagnosis of dementia. Compared with those receiving usual care, RAMP-DM participants had a lower risk of developing all-cause dementia (adjusted hazard ratio [aHR], 0.72; 95% CI, 0.68-0.77; P < .001), Alzheimer disease (aHR, 0.85; 95% CI, 0.76-0.96; P = .009), vascular dementia (aHR, 0.61; 95% CI, 0.51-0.73; P < .001), and other or unspecified dementia (aHR, 0.71; 95% CI, 0.66-0.77; P < .001). Compared with having a mean HbA1C level during the first 3 years after cohort entry between 6.5% and 7.5%, a higher risk of dementia incidence was detected for patients with a 3-year mean HbA1C level greater than 8.5% (aHR, 1.54; 95% CI, 1.31-1.80]), between 7.5% and 8.5% (aHR, 1.33; 95% CI, 1.19-1.48), between 6% and 6.5% (aHR, 1.17; 95% CI, 1.07-1.29), and 6% or less (aHR, 1.39; 95% CI, 1.24-1.57).

Conclusions and Relevance

In this cohort study of patients with T2D, the findings strengthened evidence of an association of glycemic control with dementia incidence, and revealed that a multidisciplinary primary care diabetes management program was associated with beneficial outcomes for T2D patients against dementia and its major subtypes. A moderate glycemic control target of HbA1C between 6.5% and 7.5% was associated with lower dementia incidence.

Fasting glucose variability and risk of dementia in Parkinson's disease: a 9-year longitudinal follow-up study of a nationwide cohort

Background

Diabetes is associated with an increased risk of Parkinson's disease dementia (PDD); however, it is unknown whether this association is dependent on continuous hyperglycemia, hypoglycemic events, or glycemic variability. We aimed to investigate the relationship between visit-to-visit fasting glucose variability and PDD development in patients with Parkinson's disease (PD).

Methods

Using data from the Korean National Health Insurance Service, we examined 9,264 patients aged ≥40 years with de novo Parkinson's disease (PD) who underwent ≥3 health examinations and were followed up until December 2019. Glucose variability was measured using the coefficient of variation, variability independent of the mean, and average real variability. Fine and Gray competing regression analysis was performed to determine the effect of glucose variability on incident PDD.

Results

During the 9.5-year follow-up period, 1,757 of 9,264 (19.0%) patients developed PDD. Patients with a higher visit-to-visit glucose variability had a higher risk of future PDD. In the multivariable adjusted model, patients with PD in the highest quartile (subdistribution hazard ratio [SHR] = 1.50, 95% CI 1.19 to 1.88), quartile 3 (SHR = 1.29, 95% CI 1.02 to 1.62), and quartile 2 (SHR = 1.30, 95% CI 1.04 to 1.63) were independently associated with a higher risk of PDD than those in the lowest quartile.

Conclusion

We highlighted the effect of long-term glucose variability on the development of PDD in patients with PD. Furthermore, our findings suggest that preventive measures for constant glucose control may be necessary to prevent PDD.

Correlation between long-term glycemic variability and cognitive function in middle-aged and elderly patients with type 2 diabetes mellitus: a retrospective study

Objective

To investigate the correlation between long-term glycemic variability and cognitive function in middle-aged and elderly patients with type 2 diabetes mellitus (T2DM).

Methods

This retrospective analysis includes 222 patients hospitalized at Second Affiliated Hospital of Anhui Medical University from June 2021 to June 2023. Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE). All patients were categorized into the MCI group and the non-MCI group based on their MoCA score. Long-term blood glucose fluctuations were measured using glycated hemoglobin A1c standard deviation (HbA1c-SD) and fasting plasma glucose standard deviation (FPG-SD). The study compared general clinical data, blood biochemical indicators, and glycemic variability indicators between the two groups. The differences between the groups were compared using t-test, Chi-Square Test, or Mann-Whitney U test. Kendall's correlation analysis, multivariate logistic regression analysis and ROC curve correlation analysis were further used to analyze the correlation and diagnostic power.

Results

The differences in age, MoCA scores, MMSE scores, HOMA-β, HbA1c-M, HbA1c-SD, FPG-M, FPG-SD, eGFR, Smoking, GLP-1RA and SGLT-2i usage were statistically significant between the two groups (P < 0.05). Kendall's correlation analysis showed that age, HbA1c-M, HbA1c-SD, FPG-M, and FPG-SD was negatively correlated with MoCA scores; meanwhile, the HOMA-β, and eGFR was positively correlated with MoCA scores. Multiple logistic regression analysis revealed that HbA1c-SD, FPG-SD and Smoking were risk factors for cognitive dysfunction, while eGFR, GLP-1RA and SGLT-2i usage was a protective effect. The area under the curve (AUC) values for predicting MCI prevalence were 0.830 (95% CI [0.774-0.877], P < 0.001) for HbA1c-SD, 0.791 (95% CI [0.655-0.808], P < 0.001) for FPG-SD, and 0.698 (95% CI [0.633-0.757], P < 0.001) for eGFR. The optimal diagnostic values were 0.91, 1.32, and 74.81 ml/min/1.73 m2 for HbA1c-SD, FPG-SD, and eGFR, respectively.

Conclusions

Cognitive function in middle-aged and elderly T2DM patients is influenced by long-term blood glucose variability, with poorer cognitive function observed in individuals with higher blood glucose variability. The impact of HbA1c-SD on MCI exhibited a greater magnitude compared to that of PFG-SD and smoking. Additionally, renal function, GLP-1RA and SGLT-2i usage exert positive effects on cognitive function.

Sarcopenia and diabetes-induced dementia risk

This study aimed to investigate whether sarcopenia independently increases the risk of diabetes-induced dementia in elderly individuals diagnosed with type 2 diabetes mellitus. The study cohort consisted of a large sample of elderly individuals aged 60 years and above, who were diagnosed with type 2 diabetes mellitus between 2008 and 2018. To minimize potential bias and achieve covariate balance between the sarcopenia and non-sarcopenia groups, we employed propensity score matching. Various statistical analyses, including Cox regression models to assess dementia risk and associations, competing risk analysis to account for mortality and Poisson regression analysis for incidence rates, were used. Before propensity score matching, the study included 406 573 elderly type 2 diabetes mellitus patients, with 20 674 in the sarcopenia group. Following propensity score matching, the analysis included a total of 41 294 individuals, with 20 647 in the sarcopenia group and 20 647 in the non-sarcopenia group. Prior to propensity score matching, elderly type 2 diabetes mellitus patients with sarcopenia exhibited a significantly higher risk of dementia (adjusted hazard ratio: 1.12, 95% confidence interval: 1.07-1.17). After propensity score matching, the risk remained significant (adjusted hazard ratio: 1.14, 95% confidence interval: 1.07-1.21). Incidence rates of dementia were notably higher in the sarcopenia group both before and after propensity score matching, underscoring the importance of sarcopenia as an independent risk factor. Our study highlights sarcopenia as an independent risk factor for diabetes-induced dementia in elderly type 2 diabetes mellitus patients. Advanced age, female gender, lower income levels, rural residency, higher adapted diabetes complication severity index and Charlson Comorbidity Index scores and various comorbidities were associated with increased dementia risk. Notably, the use of statins was linked to a reduced risk of dementia. This research underscores the need to identify and address modifiable risk factors for dementia in elderly type 2 diabetes mellitus patients, offering valuable insights for targeted interventions and healthcare policies.

Associations of socioeconomic status and healthy lifestyle with incident early-onset and late-onset dementia: a prospective cohort study

BACKGROUND

Modifiable risk factor estimates are sparse for early-onset dementia incidence. This study aimed to estimate and compare the risk factor profiles of early-onset dementia and late-onset dementia, and to explore the complex relationships between socioeconomic status, lifestyles, and early-onset dementia risk.

METHODS

In this prospective cohort study, we used data from the UK Biobank for analysis of early-onset dementia and late-onset dementia. For early-onset dementia analyses, data were collected on those aged younger than 60 years without prevalent dementia at baseline. For late-onset dementia analyses, data were collected on those aged 65 years or older at the end of follow-up. Participants with missing information on socioeconomic factors were excluded. Two models were used to test associations between early-onset dementia incidence and socioeconomic status. The first model tested associations between socioeconomic status and early-onset and late-onset dementia incidence, adjusting for covariates. Participant socioeconomic status was defined using education level, income, and employment status via latent class analysis. The second model additionally included a healthy lifestyle score, which was constructed using data on smoking, alcohol consumption, physical activity, and the Healthy Diet Index. Incident early-onset dementia was defined as a dementia case diagnosed before 65 years of age. Multivariable-adjusted Cox proportional hazard regression models were used to estimate the hazard ratio (HR) for risk of dementia. We used multivariable-adjusted Cox proportional-hazard regression models to estimate the HR for risk of both early-onset dementia and late-onset dementia.

FINDINGS

Between 2007 and 2010, 257 345 individuals were included in the analysis of early-onset dementia, and 294 133 older individuals were included in the analysis of late-onset dementia. During a mean follow-up of 11·9-12·5 years, 502 early-onset dementia cases and 5768 late-onset dementia cases were documented. Risk factor profiles were typically dissimilar between early-onset dementia and late-onset dementia. For instance, the age and sex adjusted HR for low socioeconomic status (vs high) was 4·40 (95% CI 3·43-5·65) for early-onset dementia and 1·90 (1·74-2·07) for late-onset dementia, yielding a ratio of HRs of 2·32 (1·78-3·02). After adjusting for various risk factors, participants with low socioeconomic status (vs high) had increased risk for early-onset dementia (3·38, 2·61-4·37), and overall lifestyle mediated 3·2% (1·8-5·7) of the association. Individuals with both low socioeconomic status and unhealthy lifestyles had a higher risk of early-onset dementia (5·40, 3·66-7·97). No significant interaction was observed between lifestyle and socioeconomic status. The association between socioeconomic status and early-onset dementia seemed to be more pronounced in individuals with type 2 diabetes (HR 11·21, 95% CI 2·70-46·57).

INTERPRETATION

Early-onset dementia and late-onset dementia might have different risk factor profiles; although risk factors were similar, the magnitude of associations between risk factors and dementia incidence was greater for early-onset dementia. Only a small proportion of the socioeconomic inequity in dementia risk was mediated by healthy lifestyles, which indicates that measures other than healthy lifestyle promotion to improve social determinants of health are warranted.

FUNDING

The National Key Research and Development Program of China, the National Natural Science Foundation of China, the Hubei Province Science Fund for Distinguished Young Scholars, and the Fundamental Research Funds for the Central Universities.

Dementia risk in patients with type 2 diabetes: Comparing metformin with no pharmacological treatment

INTRODUCTION

Metformin has been suggested as a therapeutic agent for dementia, but the relevant evidence has been partial and inconsistent.

METHODS

We established a national cohort of 210,237 type 2 diabetes patients in the UK Clinical Practice Research Datalink. Risks of incident dementia were compared between metformin initiators and those who were not prescribed any anti-diabetes medication during follow-up.

RESULTS

Compared with metformin initiators (n = 114,628), patients who received no anti-diabetes medication (n = 95,609) had lower HbA1c and better cardiovascular health at baseline. Both Cox regression and propensity score weighting analysis showed metformin initiators had lower risk of dementia compared to those non-users (adjusted hazard ratio = 0.88 [95% confidence interval: 0.84-0.92] and 0.90 [0.84-0.96]). Patients on long-term metformin treatment had an even lower risk of dementia.

DISCUSSION

Metformin may act beyond its glycemic effect and reduce dementia risk to an even lower level than that of patients with milder diabetes and better health profiles.

HIGHLIGHTS

Metformin initiators had a significantly lower risk of dementia compared with patients not receiving anti-diabetes medication. Compared with metformin initiators, diabetes patients not receiving pharmacological treatment had better glycemic profiles at baseline and during follow-up. Patients on long-term metformin treatment had an even lower risk of subsequent dementia incidence. Metformin may act beyond its effect on hyperglycemia and has the potential of being repurposed for dementia prevention.

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Astragaloside IV-mediated inhibition of oxidative stress by upregulation of ghrelin in type 2 diabetes-induced cognitive impairment

This study is to observe the upregulation effect of astragaloside IV on ghrelin in diabetic cognitive impairment (DCI) rats and to investigate the pathway in prevention and treatment by reducing oxidative stress. The DCI model was induced with streptozotocin (STZ) in conjunction with a high-fat and high-sugar diet and divided into three groups: model, low-dose (40 mg/kg), and high-dose (80 mg/kg) astragaloside IV. After 30 days of gavage, the learning and memory abilities of rats, as well as their body weight and blood glucose levels, were tested using the Morris water maze and then detection of insulin resistance, SOD activity, and serum MDA levels. The whole brain of rats was sampled for hematoxylin-eosin and Nissl staining to observe pathological changes in the hippocampal CA1 region. Immunohistochemistry was used to detect ghrelin expression in the hippocampal CA1 region. A Western blot was used to determine changes in GHS-R1α/AMPK/PGC-1α/UCP2. RT-qPCR was used to determine the levels of ghrelin mRNA. Astragaloside IV reduced nerve damage, increased superoxide dismutase (SOD) activity, decreased MDA levels, and improved insulin resistance. Ghrelin levels and expression increased in serum and hippocampal tissues, and ghrelin mRNA levels increased in rat stomach tissues. According to Western blot, it increased the expression of the ghrelin receptor GHS-R1α and upregulated the mitochondrial function associated-protein AMPK-PGC-1α-UCP2. Astragaloside IV increases ghrelin expression in the brain to reduce oxidative stress and delay diabetes-induced cognitive impairment. It may be related to the promotion of ghrelin mRNA levels.

Relationship between daytime napping with the occurrence and development of diabetes: a systematic review and meta-analysis

OBJECTIVE

To determine the relationship of napping with incident diabetes risk and glycaemic control in people with diabetes.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

MEDLINE (PubMed), EMBASE, Web of Science and the Cochrane Library were searched for studies published from database inception to 9 May 2023.

ELIGIBILITY CRITERIA

Observational studies reporting the relationship of napping with diabetes or glycaemic control in patients with diabetes in adult populations were included.

DATA EXTRACTION AND SYNTHESIS

Two reviewers independently screened the literature, extracted data and assessed the quality of the included studies. The results were reported as ORs and 95% CIs, which were pooled by using fixed and random effects models, and subgroup analyses were performed. The Grading of Recommendations Assessment, Development and Evaluation method was used to assess the quality of the evidence.

RESULTS

Forty studies were included in our review. Habitual napping was associated with an increased diabetes risk (OR 1.20, 95% CI 1.14 to 1.27) and poor glycaemic control in patients with diabetes (OR 2.05, 95% CI 1.55 to 2.73). Nap durations less than 30 min were unrelated to diabetes (OR 1.05, 95% CI 0.97 to 1.14). Nap durations of 30-60 min were associated with diabetes risk (OR 1.09, 95% CI 1.02 to 1.17), but there were differences in the subgroup analysis results. Nap durations of more than 60 min significantly increased the risk of diabetes (OR 1.31, 95% CI 1.20 to 1.44).

CONCLUSIONS

Napping is associated with increased diabetes risk and poor glycaemic control, and future research will need to confirm whether there are sex and regional differences. Nap durations of more than 60 min significantly increases the risk of diabetes, and the relationship between nap duration and glycaemic control in patients with diabetes needs to be further explored in the future.

PROSPERO REGISTRATION NUMBER

CRD42021292103.

Twenty-year trajectories of cardio-metabolic factors among people with type 2 diabetes by dementia status in England: a retrospective cohort study

To assess 20-year retrospective trajectories of cardio-metabolic factors preceding dementia diagnosis among people with type 2 diabetes (T2D). We identified 227,145 people with T2D aged > 42 years between 1999 and 2018. Annual mean levels of eight routinely measured cardio-metabolic factors were extracted from the Clinical Practice Research Datalink. Multivariable multilevel piecewise and non-piecewise growth curve models assessed retrospective trajectories of cardio-metabolic factors by dementia status from up to 19 years preceding dementia diagnosis (dementia) or last contact with healthcare (no dementia). 23,546 patients developed dementia; mean (SD) follow-up was 10.0 (5.8) years. In the dementia group, mean systolic blood pressure increased 16-19 years before dementia diagnosis compared with patients without dementia, but declined more steeply from 16 years before diagnosis, while diastolic blood pressure generally declined at similar rates. Mean body mass index followed a steeper non-linear decline from 11 years before diagnosis in the dementia group. Mean blood lipid levels (total cholesterol, LDL, HDL) and glycaemic measures (fasting plasma glucose and HbA1c) were generally higher in the dementia group compared with those without dementia and followed similar patterns of change. However, absolute group differences were small. Differences in levels of cardio-metabolic factors were observed up to two decades prior to dementia diagnosis. Our findings suggest that a long follow-up is crucial to minimise reverse causation arising from changes in cardio-metabolic factors during preclinical dementia. Future investigations which address associations between cardiometabolic factors and dementia should account for potential non-linear relationships and consider the timeframe when measurements are taken.

Dementia in Diabetes: The Role of Hypoglycemia

Hypoglycemia, a common consequence of diabetes treatment, is associated with severe morbidity and mortality and has become a major barrier to intensifying antidiabetic therapy. Severe hypoglycemia, defined as abnormally low blood glucose requiring the assistance of another person, is associated with seizures and comas, but even mild hypoglycemia can cause troubling symptoms such as anxiety, palpitations, and confusion. Dementia generally refers to the loss of memory, language, problem-solving, and other cognitive functions, which can interfere with daily life, and there is growing evidence that diabetes is associated with an increased risk of both vascular and non-vascular dementia. Neuroglycopenia resulting from a hypoglycemic episode in diabetic patients can lead to the degeneration of brain cells, with a resultant cognitive decline, leading to dementia. In light of new evidence, a deeper understating of the relationship between hypoglycemia and dementia can help to inform and guide preventative strategies. In this review, we discuss the epidemiology of dementia among patients with diabetes, and the emerging mechanisms thought to underlie the association between hypoglycemia and dementia. Furthermore, we discuss the risks of various pharmacological therapies, emerging therapies to combat hypoglycemia-induced dementia, as well as risk minimization strategies.

Glycemic Control Over Multiple Decades and Dementia Risk in People With Type 2 Diabetes

Importance

The levels of glycemic control associated with the lowest risk of dementia in people with type 2 diabetes are unknown. This knowledge is critical to inform patient-centered glycemic target setting.

Objective

To examine the associations between cumulative exposure to various ranges of glycated hemoglobin (HbA1c) concentrations with dementia risk across sex and racial and ethnic groups and the association of current therapeutic glycemic targets with dementia risk.

Design, Setting, and Participants

This cohort study included members of the Kaiser Permanente Northern California integrated health care system with type 2 diabetes who were aged 50 years or older during the study period from January 1, 1996, to September 30, 2015. Individuals with fewer than 2 HbA1c measurements during the study period, prevalent dementia at baseline, or less than 3 years of follow-up were excluded. Data were analyzed from February 2020 to January 2023.

Exposures

Time-updated cumulative exposure to HbA1c thresholds. At each HbA1c measurement, participants were categorized based on the percentage of their HbA1c measurements that fell into the following categories: less than 6%, 6% to less than 7%, 7% to less than 8%, 8% to less than 9%, 9% to less than 10%, and 10% or more of total hemoglobin (to convert percentage of total hemoglobin to proportion of total hemoglobin, multiply by 0.01).

Main Outcomes and Measures

Dementia diagnosis was identified using International Classification of Diseases, Ninth Revision codes from inpatient and outpatient encounters. Cox proportional hazards regression models estimated the association of time-varying cumulative glycemic exposure with dementia, adjusting for age, race and ethnicity, baseline health conditions, and number of HbA1c measurements.

Results

A total of 253 211 participants were included. The mean (SD) age of participants was 61.5 (9.4) years, and 53.1% were men. The mean (SD) duration of follow-up was 5.9 (4.5) years. Participants with more than 50% of HbA1c measurements at 9% to less than 10% or 10% or more had greater risk of dementia compared with those who had 50% or less of measurements in those categories (HbA1c 9% to <10%: adjusted hazard ratio [aHR], 1.31 [95% CI, 1.15-1.51]; HbA1c≥10%: aHR, 1.74 [95% CI, 1.62-1.86]). By contrast, participants with more than 50% of HbA1c concentrations less than 6%, 6% to less than 7%, or 7% to less than 8% had lower risk of dementia (HbA1c<6%: aHR, 0.92 [95% CI, 0.88-0.97]; HbA1c 6% to <7%: aHR, 0.79 [95% CI, 0.77-0.81]; HbA1c 7% to <8%: aHR, 0.93 [95% CI, 0.89-0.97]).

Conclusions and Relevance

In this study dementia risk was greatest among adults with cumulative HbA1c concentrations of 9% or more. These results support currently recommended relaxed glycemic targets for older people with type 2 diabetes.

Diabetes mellitus, prediabetes and the risk of Parkinson's disease: a systematic review and meta-analysis of 15 cohort studies with 29.9 million participants and 86,345 cases

A diagnosis of diabetes mellitus and prediabetes has been associated with increased risk of Parkinson's disease (PD) in several studies, but results have not been entirely consistent. We conducted a systematic review and meta-analysis of cohort studies on diabetes mellitus, prediabetes and the risk of PD to provide an up-to-date assessment of the evidence. PubMed and Embase databases were searched for relevant studies up to 6th of February 2022. Cohort studies reporting adjusted relative risk (RR) estimates and 95% confidence intervals (CIs) for the association between diabetes, prediabetes and Parkinson's disease were included. Summary RRs (95% CIs) were calculated using a random effects model. Fifteen cohort studies (29.9 million participants, 86,345 cases) were included in the meta-analysis. The summary RR (95% CI) of PD for persons with diabetes compared to persons without diabetes was 1.27 (1.20-1.35, I2 = 82%). There was no indication of publication bias, based on Egger's test (p = 0.41), Begg's test (p = 0.99), and inspection of the funnel plot. The association was consistent across geographic regions, by sex, and across several other subgroup and sensitivity analyses. There was some suggestion of a stronger association for diabetes patients reporting diabetes complications than for diabetes patients without complications (RR = 1.54, 1.32-1.80 [n = 3] vs. 1.26, 1.16-1.38 [n = 3]), vs. those without diabetes (pheterogeneity=0.18). The summary RR for prediabetes was 1.04 (95% CI: 1.02-1.07, I2 = 0%, n = 2). Our results suggest that patients with diabetes have a 27% increased relative risk of developing PD compared to persons without diabetes, and persons with prediabetes have a 4% increase in RR compared to persons with normal blood glucose. Further studies are warranted to clarify the specific role age of onset or duration of diabetes, diabetic complications, glycaemic level and its long-term variability and management may play in relation to PD risk.

Association of Type 2 Diabetes Subgroups With Cognitive Status Without Modification From Lifestyle Intervention

CONTEXT

Type 2 diabetes is a risk factor for incident dementia but whether risk and treatment/prevention strategies differ by diabetes subgroup is unknown.

OBJECTIVE

We assessed (1) whether specific type 2 diabetes (T2D) subgroups are associated with mild cognitive impairment (MCI) or probable dementia (PD), and (2) whether T2D subgroups modified the association of the Action for Health in Diabetes (Look AHEAD) multidomain intensive lifestyle intervention (ILI) with MCI/PD.

METHODS

We included 3760 Look AHEAD participants with T2D and overweight or obesity randomly assigned to 10 years of ILI or diabetes support and education. We used k-means clustering techniques with data on age of diabetes diagnosis, body mass index, waist circumference, and glycated hemoglobin (HbA1c) to characterize diabetes subgroups at randomization. Prevalent MCI/PD were centrally adjudicated based on standardized cognitive tests and other health information 10 to 13 years after randomization. We estimated marginal probabilities for prevalent MCI/PD among T2D subgroups with adjustment for potential confounders and attrition and examined whether ILI modified any associations.

RESULTS

Four distinct T2D subgroups were identified, characterized by older age at diabetes onset (43% of sample), high HbA1c (13%), severe obesity (23%), and younger age at onset (22%). Unadjusted prevalence of MCI/PD (314 cases, 8.4%) differed across T2D subgroup (older onset = 10.5%, severe obesity = 9.0%, high HbA1c = 7.9%, and younger onset = 4.0%). Adjusted probability for MCI/PD within T2D subgroup was highest for the severe obesity subgroup and lowest for the younger onset subgroup but did not differ by ILI arm (interaction P value = 0.84).

CONCLUSIONS

Among individuals with T2D and overweight or obesity, probability of MCI/PD differed by T2D subgroup. Probability of MCI/PD was highest for a subgroup characterized by severe obesity.

CLINICALTRIALS.GOV IDENTIFIER

NCT00017953.

Association of Type 2 Diabetes Mellitus with Cognitive Function in Adults: A Prospective Cohort Study

BACKGROUND

Cognitive role of untreated type 2 diabetes mellitus (T2DM) has been less well substantiated.

OBJECTIVE

We sought to explore the prospective association of T2DM and untreated T2DM with cognitive function among middle-aged and older Chinese adults.

METHODS

Data of 7,230 participants without baseline brain damage, mental retardation, or memory-related diseases in China Health and Retirement Longitudinal Study (CHARLS) from 2011- 2012 to 2015, were analyzed. Fasting plasma glucose and self-reported information on T2DM diagnosis and treatment were assessed. Participants were categorized into normoglycemia, impaired fasting glucose (IFG), and T2DM (including untreated and treated T2DM) groups. Episodic memory and executive function were assessed by modified Telephone Interview for Cognitive Status every two years. We used generalized estimating equation model to examine the association of baseline T2DM status with cognitive function in succeedingyears.

RESULTS

Compared to those with normoglycemia, T2DM was associated with worse overall cognitive function after controlling for demographic variables, lifestyles, follow-up time, major clinical factors, and baseline cognitive function, although the associations were statistically non-significant (β= -0.19, 95% CI: -0.39, 0.00). However, a significant association was mainly observed for those with untreated T2DM (β= -0.26, 95% CI: -0.47, -0.04), especially in the domain of executive function (β= -0.19, 95% CI: -0.35, -0.03). In general, IFG and treated T2DM individuals had similar levels of cognitive function with normoglycemia participants.

CONCLUSION

Our findings supported a detrimental role of untreated T2DM on cognitive function among middle-aged and older adults. Screening and early treatment for T2DM are warranted for maintaining better cognitive function in later life.

Management of Type 2 Diabetes Mellitus in the Very Elderly: One Practice's Experience

OBJECTIVE

Type 2 diabetes mellitus (T2DM) affects 25% of adults over age 65. Nevertheless, few clinical trials include patients over age 75.

METHODS

This case series reports retrospective data on a cohort of 85 patients aged 80 and over (mean 88.1, range 80-104) with T2DM, managed by a single endocrinologist. The practice's computerized data base was searched for all patients 80 years of age and older with a diagnosis of T2DM.

RESULTS

The major observations were the significant decrease in the use of agents associated with hypoglycemia, (sulfonylureas and insulin), and the beneficial and well-tolerated use of glucagon like peptide-1 receptor analogues (GLP-1 RA). The mean A1c in the entire cohort dropped from 7.6% to 6.6% over a mean of 9 months. Nearly one-half of the cohort were treated with GLP1-RA, reflecting studies demonstrating the safety and efficacy of this class of drugs in less elderly patients. At presentation, 75% were on sulfonylurea and/or insulin; this number was reduced to 27%. Furthermore, none of the patients required short-acting (bolus) insulin to achieve the individualized A1c target.

CONCLUSION

Patients with T2DM aged 80 and over respond well to GLP1-RA drugs, drastically reducing the need for agents associated with hypoglycemia. The important question, which will require larger and prospective studies, is whether the lowering of A1c, as shown in this paper, and the use of GLP-1 RA specifically, are associated with improved morbidity and mortality in the very elderly.

Associations of Mid- and Late-Life Severe Hypoglycemic Episodes With Incident Dementia Among Patients With Type 2 Diabetes: A Population-Based Cohort Study

OBJECTIVE

Severe hypoglycemia is associated with an increased risk of dementia. We examined if the association is consistently present in mid- and late-life hypoglycemia.

RESEARCH DESIGN AND METHODS

Using health care data from Population Data BC, we created a base cohort of patients age ≥40 years with incident type 2 diabetes. Exposure was the first occurrence of severe hypoglycemia (hospitalization or physician visit). We assessed exposure versus no exposure in mid- (age 45-64 years) and late-life (age 65-84 years) cohorts. Index date was the later of the 45th birthday (midlife cohort), 65th birthday (late-life cohort), or diabetes diagnosis. Those with hypoglycemia or dementia before the index date were excluded. Patients were followed from index date until dementia diagnosis, death, emigration, or 31 December 2018. Exposure was modeled as time dependent. We adjusted for confounding using propensity score weighting. Dementia risk was estimated using cause-specific hazards models with death as a competing risk.

RESULTS

Of 221,683 patients in the midlife cohort, 1,793 experienced their first severe hypoglycemic event. Over a median of 9.14 years, 3,117 dementia outcomes occurred (32 among exposed). Of 223,940 patients in the late-life cohort, 2,466 experienced their first severe hypoglycemic event. Over a median of 6.7 years, 15,997 dementia outcomes occurred (158 among exposed). The rate of dementia was higher for those with (vs. without) hypoglycemia in both the mid- (hazard ratio 2.85; 95% CI 1.72-4.72) and late-life (2.38; 1.83-3.11) cohorts.

CONCLUSIONS

Both mid- and late-life hypoglycemia were associated with approximately double the risk of dementia, indicating the need for prevention throughout the life course of those with diabetes.

Differences in the Cognitive Function of Mexican Adults Aged 60 and Older with Self-Reported Diabetes in 2001 and 2018

BACKGROUND

The prevalence of type 2 diabetes in Mexico has nearly doubled for adults aged ≥60. Increases in education and healthcare resources to manage chronic conditions have contributed to population-level increases in the cognitive functioning of older adults. However, research has not focused on older adults with chronic conditions such as diabetes.

OBJECTIVE

Our objective was to compare the cognitive functioning of Mexican adults aged ≥60 with diabetes in 2001 and 2018.

METHODS

Data came from Mexican Health and Aging Study. Our study used a cross-sectional design and included participants aged ≥60 with self-reported diabetes during the 2001 (n = 1,052, mean age = 68.4, female = 59.6%) and 2018 (n = 2,469, mean age = 70.6, female = 62.0%) observation waves. Five cognitive tests were used to create a score of global cognition. Generalized estimating equations were used to compare global cognition in 2001 to 2018.

RESULTS

Older adults in 2018 had more education and were more likely than older adults in 2001 to take oral medication for diabetes, insulin, and to check blood sugar weekly. Older adults in 2018 had higher global cognition than in 2001 when adjusting for age, gender, education, and health insurance coverage (b = 0.38, SE = 0.02). This statistically significant difference remained after adjusting for health conditions, health behaviors, and diabetes management behaviors.

CONCLUSIONS

Older adults in Mexico with self-reported diabetes in 2018 had higher cognitive function than in 2001. Future research is needed to investigate causes of the cohort differences in cognitive functioning among Mexican older adults with self-reported diabetes.

[Geriatric aspects for the management of diabetes mellitus (Update 2023)]

There is a high prevalence of diabetes mellitus in the elderly population of industrial countries. The present article provides recommendations for the screening, prevention and treatment of elderly diabetic patients according to current scientific evidence.

Application of Grey Relational Analysis to Predict Dementia Tendency by Cognitive Function, Sleep Disturbances, and Health Conditions of Diabetic Patients

Background: The number of elderly diabetic patients has been increasing recently, and these patients have a higher morbidity of dementia than those without diabetes. Diabetes is associated with an increased risk for the development of dementia in elderly individuals, which is a serious health problem. Objectives: The primary aim was to examine whether diabetes is a risk factor for dementia among elderly individuals. The secondary aim was to apply grey theory to integrate the results and how they relate to cognitive impairments in elderly diabetic patients and to predict which participants are at high risk of developing dementia. Methods: Two hundred and twenty patients aged 50 years or older who were diagnosed with diabetes mellitus were recruited. Information on demographics, disease characteristics, activities of daily living, Mini Mental State Examination, sleep quality, depressive symptoms, and health-related quality of life was collected via questionnaires. The grey relational analysis approach was applied to evaluate the relationship between the results and health outcomes. Results: A total of 13.6% of participants had cognitive disturbances, of whom 1.4% had severe cognitive dysfunction. However, with regard to sleep disorders, 56.4% had sleep disturbances of varying degrees from light to severe. Further investigation is needed to address this problem. A higher prevalence of sleep disturbances among diabetic patients translates to a higher degree of depressive symptoms and a worse physical and mental health-related quality of life. Furthermore, based on the grey relational analysis, the grey relation coefficient varies from 0.6217~0.7540. Among the subjects, Participant 101 had the highest value, suggesting a need for immediate medical care. In this study, we observed that 20% of the total participants, for whom the grey relation coefficient was 0.6730, needed further and immediate medical care.

Sugar-Sweetened Coffee Intake and Blood Glucose Management in Korean Patients with Diabetes Mellitus

One of the most frequently consumed beverages by Korean adults is 3-in-1 coffee (mixed coffee) with sugar and creamer. Hence, understanding the effect of sugar-sweetened coffee (SSC) consumption on blood sugar levels in patients with diabetes mellitus (DM) is important. This study was conducted using the Korea National Health and Nutrition Examination Survey data from 2008 to 2020. In total, 5671 patients with DM were included in the analysis. Coffee consumption patterns were assessed using a 24 h recall. Fasting blood glucose (FBG) and hemoglobin A1c (HbA1c) levels were used to evaluate whether patients reached the glycemic control targets defined by the Korean Diabetes Association. In total, 46.57% of patients with DM included in this analysis consumed SSC. Patients who frequently consumed SSC had significantly higher FBG and HbA1c levels than those who did not (both p for trend <0.01). In a multivariate logistic regression model, the odds ratios of not achieving the target FBG and HbA1c levels were 1.24 (95% confidence interval [CI]: 1.03−1.48, p for trend = 0.01) and 1.29 (95% CI: 1.05−1.58, p for trend = 0.009), respectively. Frequent consumption of SSC can cause difficulty in FBG and HbA1c management in patients with DM.

A Diabetes Genetic Risk Score Is Associated With All-Cause Dementia and Clinically Diagnosed Vascular Dementia in the Million Veteran Program

OBJECTIVE

Diabetes and dementia are diseases of high health care burden worldwide, and studies have shown that diabetes is associated with an increased relative risk of dementia. We set out to examine whether type 2 diabetes-associated genetic variants were associated with dementia and whether they differed by race/ethnicity or clinical dementia diagnosis.

RESEARCH DESIGN AND METHODS

We evaluated associations of two type 2 diabetes genetic risk scores (GRS and GRS-nonAPOE: a score without rs429358, a variant associated with Alzheimer disease [AD]) with three classifications of clinical dementia diagnoses in the Million Veteran Program (MVP): all-cause dementia, vascular dementia (VaD), and AD. We conducted our analysis stratified by European (EUR), African (AFR), and Hispanic (HIS) races/ethnicities.

RESULTS

In EUR, we found associations of the GRS with all-cause dementia (odds ratio [OR] 1.06, P = 1.60e-07) and clinically diagnosed VaD (OR 1.12, P = 5.2e-05) but not with clinically diagnosed AD (OR 1.02, P = 0.43). The GRS was not associated with any dementia outcome in AFR or HIS. When testing with GRS-nonAPOE, we found that effect size estimates in EUR increased and P values decreased for all-cause dementia (OR 1.08, P = 2.6e-12), for VaD (OR 1.14, P = 7.2e-07), and for AD (OR 1.06, P = 0.018). For AFR, the association of GRS-nonAPOE and clinically diagnosed VaD (OR 1.15, P = 0.016) was statistically significant. There were no significant findings for HIS.

CONCLUSIONS

We found evidence suggesting shared genetic pathogenesis of diabetes with all-cause dementia and clinically diagnosed VaD.

Fasting Glucose Variability and the Risk of Dementia in Individuals with Diabetes: A Nationwide Cohort Study

BACKGROUND

We investigated whether fasting glucose (FG) variability could predict the risk of dementia.

METHODS

This cohort study analyzed data from Koreans with diabetes after at least three health examinations by the Korean National Health Insurance Corporation between 2005 and 2010, which included at least one examination between 2009 and 2010. A total of 769,554 individuals were included, excluding those aged <40 years and those with dementia. FG variability was measured using the variability independent of the mean (FG-VIM). The incidence of dementia was defined by the International Classification of Diseases 10th Revision codes and prescription of anti-dementia medication and was subdivided into Alzheimer's disease (AD) and vascular dementia (VD).

RESULTS

During the 6.9-year follow-up, 54,837, 41,032, and 6,892 cases of all-cause dementia, AD, and VD, respectively, were identified. Cox proportional regression analyses showed that as the FG-VIM quartile increased, the risk of dementia serially increased after adjustment for metabolic factors, income status, and diabetes-related characteristics, including the mean FG. Participants in FG-VIM quartile 4 showed a 18%, 19%, and 17% higher risk for all-cause dementia, AD, and VD, respectively, than those in quartile 1; this particularly included non-obese patients with a longer duration of diabetes, high FG levels, dyslipidemia, and those taking glucose-lowering medications. Conversely, the baseline FG status and dementia showed a U-shaped association.

CONCLUSION

Increased FG variability over 5 years can predict the risk of dementia in individuals with diabetes in Korea. This finding was more pronounced in patients with less favorable metabolic profiles.

Hypoglycaemia and the risk of dementia: a population-based cohort study using exposure density sampling

BACKGROUND

Previous studies have shown hypoglycaemia to be associated with an increased risk of dementia; however, there are several design challenges to consider. The objective of this study is to assess the association between hypoglycaemia and dementia while addressing these challenges using a lag period, exposure density sampling (EDS) and inverse probability of treatment weighting (IPTW).

METHODS

This was a population-based cohort using data (1996-2018) from British Columbia, Canada. From a cohort of incident type 2 diabetes patients aged 40-70 years, we created a dynamic sub-cohort of hypoglycaemia-exposed (≥1 episode requiring hospitalization or a physician visit) and unexposed individuals using EDS, in which four unexposed individuals per one exposed were randomly selected into risk sets based on diabetes duration and age. Follow-up was until dementia diagnosis, death, emigration or 31 December 2018. Those diagnosed with dementia within 2 years of follow-up were censored. We adjusted for confounding using IPTW and estimated the hazard ratio (HR, 95% CI) of dementia using weighted conditional cause-specific hazards risk models with death as a competing risk.

RESULTS

Among 13 970 patients with incident type 2 diabetes, 2794 experienced hypoglycaemia. There were 329 dementia events over a median (interquartile range: IQR) follow-up of 5.03 (5.7) years. IPTW resulted in well-balanced groups with weighted incidence rates (95% CI) of 4.59 (3.52, 5.98)/1000 person-years among exposed and 3.33 (2.58, 3.88)/1000 person-years among unexposed participants. The risk of dementia was higher among those with hypoglycaemia (HR, 1.83; 95% CI 1.31, 2.57).

CONCLUSIONS

After addressing several methodological challenges, we showed that hypoglycaemia contributes to an increased risk of all-cause dementia among patients with type 2 diabetes.

The association between sodium-glucose cotransporter 2 inhibitors and incident dementia: A nationwide population-based longitudinal cohort study

BACKGROUND

The association of the use of sodium-glucose cotransporter 2 (SGLT2) inhibitor and incident dementia remains unclear. This study aimed to evaluate the risk of incident dementia with the use of SGLT2 inhibitor.

METHODS

This is a population-based cohort study utilizing Taiwan's National Health Insurance Research Database. Each patient who took SGLT2 inhibitors was assigned to the SGLT2 inhibitor group, whereas 1:1 propensity score-matched randomly selected patients who were nonusers of SGLT2 inhibitors were assigned to the non-SGLT2 inhibitor group. The study outcome was incident dementia.

RESULTS

A total of 976,972 patients newly diagnosed with type 2 diabetes mellitus (DM) between 2011 and 2018 were included in this study. After the patients' propensity score matching by age, sex, duration of DM, comorbidities and drug index date of the patients, a total of 103,247 patients in the SGLT2 inhibitor group and 103,247 in the non-SGLT2 inhibitor group were enrolled for analysis. The SGLT2 inhibitor group was associated with a lower risk of incident dementia (adjusted hazard ratio: 0.89, 95% confidence interval: 0.82-0.96; p = .0021). Diabetic complications were significantly lower in the SGLT2 inhibitor group compared with the non-SGLT2 group. Sensitivity analysis was also consistent with the main analysis.

CONCLUSIONS

Patients with type 2 DM who were prescribed SGLT2 inhibitors were associated with a lower risk of incident dementia compared with those not prescribed SGLT2 inhibitors in real-world practice.

Evaluating diabetic ketoacidosis via a MOF sensor for fluorescence imaging of phosphate and pH

Herein, a new type of composite metal-organic framework sensor for evaluating diabetic ketoacidosis was designed and prepared using in situ fluorescence imaging of phosphate and pH, which provides a new way to effectively evaluate the diabetic complication-ketoacidosis in the early clinical stage.

Association between hypoglycemia and dementia in patients with diabetes: a systematic review and meta-analysis of 1.4 million patients

BACKGROUND

Diabetes mellitus (DM) is known to be a risk factor for dementia. However, it is unclear if hypoglycemic events play a role in the risk of dementia. We aimed to systematically review evidence on the risk of dementia in DM patients based on prior hypoglycemic events.

METHODS

PubMed, Embase, ScienceDirect, CENTRAL, and Google Scholar databases were searched till 15th November 2021 for cohort studies assessing the risk of dementia based on prior hypoglycemic events in DM patients. Adjusted data were pooled in a random-effects model.

RESULTS

Ten studies with a total of 1,407,643 patients were included. Pooled analysis of all ten studies indicated that hypoglycemic episodes were associated with a statistically significant increase in the risk of dementia in DM patients as compared to those not experiencing hypoglycemic episodes (HR: 1.44 95% CI: 1.26, 1.65 I² = 89% p < 0.00001). The results did not change on the exclusion of any study. Sub-group analysis based on the study population, type of study, adjustment for glycated hemoglobin, gender, and the number of hypoglycemic episodes also presented similar results.

CONCLUSIONS

Evidence from observational studies with a large sample size indicates that DM patients with hypoglycemic episodes are at increased risk of dementia. Anti-hyperglycemic drugs should be adequately tailored in these patients to avoid the risk of dementia.

Cognitive impairment and type 2 diabetes mellitus: Focus of SGLT2 inhibitors treatment

Gliflozins are a novel class of oral anti-diabetic drugs, acting as inhibitors of sodium-glucose co-transporters (SGLTs) through the proximal convoluted tubules (PCT) and intestinal epithelium. The sodium-glucose co-transporters 2 (SGLT2) are mainly expressed in S1 and S2 segments of the proximal convoluted tubule in the kidneys. Clinical guidelines recommend their use especially in Type 2 Diabetes mellitus (T2DM) patients with vascular complications and/or heart failure highlighting the importance of sodium-glucose co-transporter 2 inhibitors (SGLT2i) pleiotropic effects. Interestingly, cognitive decline is a widely recognized complication of T2DM and, in addition, to clarify its pathophysiology, there is an urgent need to understand how and if diabetes therapies can control diabetes-related cognitive dysfunction. At the time, although SGLT2 proteins are present in the Central Nervous System (CNS), the SGLT2i effects on cognitive impairments remain partly unknown. In pre-clinical studies, SGLT2i ameliorates cognitive dysfunction in obese and T2DM mice, reducing oxidative stress, neuroinflammation and improving neuronal plasticity and mitochondrial brain pathway. In addition, SGLT2i could bring back mTOR to a physiological state of activation, stopping neurodegenerative diseases' onset or progression. Instead, clinical studies on T2DM-related cognitive dysfunction treated by SGLT2i are much more limited. For these reasons, further studies are needed to better elucidate if SGLT2i therapy can affect T2DM-related cognitive decline. In this scenario, this review aims to summarize the state of knowledge on the role of SGLT2i in T2DM-related cognitive dysfunction and stimulate new clinical trials.

Association of serum 25-hydroxyvitamin D concentrations with risk of dementia among individuals with type 2 diabetes: A cohort study in the UK Biobank

BACKGROUND

Several epidemiological studies have suggested that vitamin D status is associated with risk of dementia in general populations. However, due to the synergistic effect between diabetic pathology and neuroinflammation, and the prothrombotic profile in patients with diabetes, whether vitamin D is associated with risk of dementia among patients with diabetes is unclear. This study aimed to investigate the associations of circulating vitamin D levels with risks of all-cause dementia, Alzheimer disease (AD), and vascular dementia (VD) among adults with type 2 diabetes (T2D).

METHODS AND FINDINGS

This study included 13,486 individuals (≥60 years) with T2D and free of dementia at recruitment (2006-2010) from the UK Biobank study. Serum 25-hydroxyvitamin D (25[OH]D) concentrations were measured using the chemiluminescent immunoassay method at recruitment. Serum 25(OH)D ≥ 75 nmol/L was considered sufficient, according to the Endocrine Society Clinical Practice Guidelines. Incidence of all-cause dementia, AD, and VD cases was ascertained using electronic health records (EHRs). Each participant's person-years at risk were calculated from the date of recruitment to the date that dementia was reported, date of death, date of loss to follow-up, or 28 February 2018, whichever occurred first. Among the 13,486 individuals with T2D (mean age, 64.6 years; men, 64.3%), 38.3% had vitamin D ≥ 50 nmol/L and only 9.1% had vitamin D ≥ 75 nmol/L. During a mean follow-up of 8.5 years, we observed 283 cases of all-cause dementia, including 101 AD and 97 VD cases. Restricted cubic spline analysis demonstrated a nonlinear relationship between serum 25(OH)D and risk of all-cause dementia (Pnonlinearity < 0.001) and VD (Pnonlinearity = 0.007), and the nonlinear association reached borderline significance for AD (Pnonlinearity = 0.06), with a threshold at around a serum 25(OH)D value of 50 nmol/L for all the outcomes. Higher serum levels of 25(OH)D were significantly associated with a lower risk of all-cause dementia, AD, and VD. The multivariate hazard ratios and 95% confidence intervals for participants who had serum 25(OH)D ≥ 50 nmol/L, compared with those who were severely deficient (25[OH]D < 25 nmol/L), were 0.41 (0.29-0.60) for all-cause dementia (Ptrend < 0.001), 0.50 (0.27-0.92) for AD (Ptrend = 0.06), and 0.41 (0.22-0.77) for VD (Ptrend = 0.01). The main limitation of the current analysis was the potential underreporting of dementia cases, as the cases were identified via EHRs.

CONCLUSIONS

In this study, we observed that higher concentrations of serum 25(OH)D were significantly associated with a lower risk of all-cause dementia, AD, and VD among individuals with T2D. Our findings, if confirmed by replication, may have relevance for dementia prevention strategies that target improving or maintaining serum vitamin D concentrations among patients with T2D.

HbA1c Variability and the Risk of Dementia in Patients with Diabetes: A Meta-Analysis

BACKGROUND

Variability of HbA1c has been related to the incidence micro and macrovascular complications in patients with diabetes. However, the association between of visit-to-visit variability of HbA1c and risk of dementia has not been fully determined. A meta-analysis was performed to comprehensively evaluate the above association.

METHODS

Medline, Embase, and Web of Science databases were searched for longitudinal follow-up studies comparing the incidence of dementia in diabetic patients with higher or lower variability of HbA1c. A random-effect model incorporating the potential heterogeneity among the included studies were used to pool the results.

RESULTS

Five retrospective studies with 577592 diabetic patients were included, and 99% of them were with type 2 diabetes mellitus (T2DM). With a mean follow-up duration of 6.3 years, 31963 patients had newly diagnosed dementia. Pooled results showed that diabetic patients with higher HbA1c variability was associated with higher risk of dementia, as evidenced by studies with coefficient of variation (CV: hazard ratio (HR): 1.06; 95% confidence interval (CI): 1.003-1.120; p=0.04; I ² = 47%) and standard deviation (SD : HR: 1.19; 95% CI: 1.06-1.32; p=0.002; I ² = 0%) of HbA1c in continuous variables, and CV of HbA1c (HR: 1.18; 95% CI: 1.08-1.28; p < 0.001; I ² = 31%) in categorized variables.

CONCLUSIONS

Higher variability of HbA1c is associated with a higher incidence of dementia in patients with diabetes.