Linking glycemic control and executive function in rural older adults with diabetes mellitus

Event-Related Potential Changes Following 12-week Yoga Practice in T2DM Patients: A Randomized Controlled Trial

Introduction. Type 2 diabetes patients are more likely to experience cognitive decline (1.5%) and dementia (1.6%) than healthy individuals. Although cognitive impairment adversely affects Type 2 diabetes mellitus (T2DM) patients, it is the least addressed complication of T2DM patients. Objective. The present study attempts to examine the changes in cognitive performance of T2DM patients and the probable factors contributing to the changes following 12-week yoga practice. Methods. The current study is a parallel group randomized controlled trial that compared the outcomes of the participants randomized to a yoga group (YG) (n = 25) and to a wait-list control group (n = 29). The study assessed N200 and N450 event-related potential (ERP) components following the Stroop task, heart rate variability (HRV) and HbA1c before and after the intervention. Results. The mean amplitude of the N200 ERP component showed a significant group difference after the intervention, demonstrating an improved neural efficiency in the process of conflict monitoring and response inhibition. No differences were present for the N450 component. T2DM patients showed reduced heart rate and increased mean RR following yoga practice without any corresponding changes in other HRV parameters, demonstrating an overall improvement in cardiac activity. Along with that yoga practice also reduced HbA1c levels in T2DM patients, indicating improved glycemic control. Moreover, HbA1c levels were negatively correlated with reaction time after the intervention, indicating an impact of glycemic control on cognitive performance. Conclusion. The 12-week yoga practice improved cognitive performance by enhancing the processes of conflict monitoring and response inhibition. Further, improved cognitive performance postintervention was facilitated by improved glycemic control.

Cognitive impairment burden in older and younger adults across the kidney transplant care continuum

BACKGROUND

Younger kidney transplant (KT) candidates and recipients may have cognitive impairment due to chronic diseases and reliance on dialysis.

METHODS

To quantify cognitive impairment burden by age across the KT care continuum, we leveraged a two-center cohort study of 3854 KT candidates at evaluation, 1114 recipients at admission, and 405 recipients at 1-year post-KT with measured global cognitive performance (3MS) or executive function (Trail Making Test). We also estimated burden of severe cognitive impairment that affects functional dependence (activities of daily living [ADL] < 6 or instrumental activities of daily living [IADL] < 8).

RESULTS

Among KT candidates, global cognitive impairment (18-34 years: 11.1%; 35-49 years: 14.0%; 50-64 years: 19.5%; ≥65 years: 22.0%) and severe cognitive impairment burden (18-34 years: 1.1%; 35-49 years: 3.0%; 50-64 years: 6.2%; ≥65 years: 7.7%) increased linearly with age. Among KT recipients at admission, global cognitive impairment (18-34 years: 9.1%; 35-49 years: 6.1%; 50-64 years: 9.3%; ≥65 years: 15.7%) and severe cognitive impairment burden (18-34 years: 1.4%; 35-49 years: 1.4%; 50-64 years: 2.2%; ≥65 years: 4.6%) was lower. Despite lowest burden of cognitive impairment among KT recipients at 1-year post-KT across all ages (18-34 years: 1.7%; 35-49 years: 3.4%; 50-64 years: 4.3%; ≥65 years: 6.5%), many still exhibited severe cognitive impairment (18-34 years: .0%; 35-49 years: 1.9%; 50-64 years: 2.4%; ≥65 years: 3.5%).

CONCLUSION

Findings were consistent for executive function impairment. While cognitive impairment increases with age, younger KT candidates have a high burden comparable to community-dwelling older adults, with some potentially suffering from severe forms. Transplant centers should consider routinely screening patients during clinical care encounters regardless of age.

Impact of Cognitive Impairment on Adherence to Treatment and Self-Care in Patients with Type 2 Diabetes Mellitus

BACKGROUND

Elderly patients with diabetes have a significantly increased prevalence of mild cognitive impairment compared with people of similar age without diabetes. Tasks related to diabetes self-management involve multiple cognitive skills and processes, such as memory, attention, planning, and calculating. Impaired cognitive function can threaten the patient's ability to perform self-monitoring. The objectives of the study were: to assess cognitive deficits and the level of self-care in elderly patients with diabetes, to identify correlations between cognitive deficits and self-care, and to determine which variables influence self-care behaviors and cognitive deficits.

METHODS

The study involved 169 patients with type 2 DM. Standardized tools were used: Mini-mental State Examination (MMSE) to assess cognitive function and the Self-Care of Diabetes Inventory (SCODI) to assess the level of self-care. Socioclinical data were taken from the hospital records.

RESULTS

56.8% of patients had cognitive impairment (MMSE≤26). In the comparative analysis, patients with cognitive impairment had significantly lower results in all domains of the SCODI: self-care maintenance (72.9 vs 75), self-care monitoring (53.1 vs 56.3), self-care management (71.9 vs 84.4), self-care confidence (79.5 vs 86.4). Correlation analysis showed that the MMSE score correlates significantly and positively (p˂0.05; r˃0) with all SCODI subscales, and the higher the MMSE score the higher the level of self-care (A: r=0.252, B: r=0.244, C: r=0.019, D: r=0.28).

CONCLUSION

In this elderly type 2 diabetes population, and using only one test to verify the cognitive function, self-care management was worse in terms of self-care management (blood glucose control). Cognitive function components are independent determinants of self-care in patients with type 2 diabetes. Recall is an independent predictor of self-care maintenance, and writing a predictor of self-care monitoring.

Relationships Between Cognitive Impairment and Self-Management in Older Adults With Type 2 Diabetes: An Integrative Review

Cognitive impairment is common in older adults with diabetes and is likely to negatively affect their daily diabetes self-management behaviors (DSMB). The primary aim of this integrative review was to summarize and synthesize the current state of knowledge about relationships between cognitive impairment and DSMB in older adults with type 2 diabetes. The review was guided by Whittemore and Knafl's 2005 framework, and study quality was evaluated using the Crowe Critical Appraisal Tool. Of 27 studies reviewed, 24 were quantitative, and three were qualitative. Heterogeneity was noted in study design, participant characteristics, and measures of cognitive function and DSMB. Overall, global cognitive impairment and executive function impairment related particularly to poor medication management and glucose self-monitoring. The findings supported the need for routine cognitive assessment of older adults with diabetes, but more longitudinal and interventional studies are needed to better define cognitive impairment-DSMB relationships. [Research in Gerontological Nursing, 14(2), 104-112.].

Association between microstructural white matter abnormalities and cognitive functioning in patients with type 2 diabetes mellitus: a diffusion tensor imaging study

Background

Diffusion tensor imaging (DTI) technique is important for exploring more sensitive imaging-based biomarkers in prevention and early treatment of cognitive dysfunction induced by type 2 diabetes mellitus (DM).

Objectives

To predict early cognitive dysfunction and detection of microstructural white matter changes in patients with type 2 DM by diffusion tensor imaging.

Patients and methods

A case-control study included thirty patients aged ≥ 18 years old of both sexes with type 2 DM and 30 controls. All subjects underwent to Montreal Cognitive Assessment (MoCA) “Arabic version”: to detect mild cognitive impairment (MCI) and diffusion tensor imaging study (DTI).

Results

Mild cognitive impairment is related to type 2 DM (56.7% of diabetic group), reduced fractional anisotropy (FA) values, and elevated mean diffusivity (MD) values were related to cognitive impairment evaluated through Montreal Cognitive Assessment (MoCA) in patients with type 2 DM.

Conclusion

The integrity of the white matter measured using DTI vary in MCI diabetics compared with non-MCI diabetics. Such changes have major implications on the cognitive function.

Executive Function and Diabetes: A Clinical Neuropsychology Perspective

Objective

Diabetes is a global public health concern. Management of diabetes depends on successful implementation of strategies to alleviate decline in executive functions (EFs), a characteristic of diabetes progression. In this review, we describe recent research on the relationship between diabetes and EF, summarize the existing evidence, and put forward future research directions and applications.

Methods

Herein, we provide an overview of recent studies, to elucidate the relationship between DM and EF. We identified new screening objectives, management tools, and intervention targets for diabetes management. We also discuss the implications for clinical practice.

Results

In both types 1 and 2 diabetes mellitus (DM), hyperglycemia substantially impairs EF in people of all age groups and ethnicities. Hypoglycemia can similarly impair EF. Interestingly, a decline in EF contributes to DM progression. Glucose dysregulation and EF decline exacerbate each other in a vicious cycle: poor blood glucose control, impaired EF, diabetes management task failure, then back to poor blood glucose control. Many pathophysiological indexes (e.g., obesity, metabolic index, inflammatory and immune factors), neuropsychological indexes (e.g., compliance, eating habits, physical exercise, sleep, and depression), and genetic factors are changed by this pathological interaction between DM and EF. These changes can provide insight into the pathophysiological mechanisms of diabetes-related EF decline.

Conclusion

Further studies, including large-scale prospective and randomized controlled trials, are needed to elucidate the mechanism of the interaction between diabetes and EF and to develop novel strategies for breaking this cycle.

Risk of mini-mental state examination (MMSE) decline in the elderly with type 2 diabetes: a Chinese community-based cohort study

BACKGROUND

We aimed to investigate the correlation of factors involved in the change of Mini-Mental State Examination (MMSE) and type 2 diabetes in the elderly.

METHODS

This study was a secondary analysis of a prospective cohort study. Type 2 diabetes patients aged > 55 years were recruited and assigned into three groups based on their glycated hemoglobin (HbA1c) levels: HbA1c < 7, 7% ≤ HbA1c < 8% and HbA1c ≥8%. MMSE decline was considered the endpoint. Factors related to MMSE decline were identified by univariate and multivariate regression analyses.

RESULTS

Altogether, 1519 subjects were included, 883 in the Low group, 333 in the Median group, and 303 in the High group. Age ≥ 75 years, education below elementary school level, not participating in seminars or consultation on healthcare, physical activity less than 30 min/day, cerebrovascular disease history, MMSE score at baseline, and HBA1c ≥8% were associated with cognitive decline by univariate and multivariate analysis. When the other factors were adjusted for, HBA1c ≥8% was independently associated with the severity of cognitive decline (β = 0.58, 95%CI:0.06-1.11, P = 0.029) and the occurrence of cognitive decline (odds ratio (OR) = 1.55, 95%CI:1.13-2.12, P = 0.007).

CONCLUSIONS

In elderly patients with type 2 diabetes, HbA1c ≥8% is an independent factor for cognitive decline and is also associated with the severity of the cognitive decline.

Cross-Cultural Reliability of an Arabic Version of the Self-Efficacy for Managing Chronic Disease 6-Item Scale in Arab Patients with Diabetes mellitus

INTRODUCTION

Arab nations have the second highest diabetes mellitus (DM) prevalence in the world. There is a growing interest in self-management programs that emphasize patient's central role in managing type 2 DM.

AIM OF THE STUDY

To validate an Arabic version of the Self-Efficacy for Managing Chronic Disease 6-Item Scale (SEM6S) among Arab type 2 DM patients and to explore factors associated with self-efficacy measured with the SEM6S.

METHODS

Cross-sectional study on 302 Arab patients with T2DM of three different nationalities (Egyptian, Saudi, Kuwaiti).The SEM6S was translated using forward-backward method, and its reliability was determined by calculating Cronbach's alpha. A regression model was used to examine variables associated with self-efficacy in Arab patients with T2DM.

RESULTS

Questionnaire was successfully translated without language or content-related problem. The mean age of participants was 47.71±14.7 years with equally represented sexes. The mean total score of the SEM6S was 5.99±1.86. The scale psychometric properties was reproducible (ICC=0.61-0.71) with good reliability (Cronbach's alpha=0.79). Statistically significant increase in self-efficacy was observed in patients <30 years, uncomplicated DM, DM with hypertension, and in patients who had physical activity > 60min per day. Also, a bimodal increase in self-efficacy was detected in patients with DM<5 years and 10.1-15 years. After regression analysis, physical activity was significantly positively correlated with self-efficacy (β=0.8, P=0.01), and duration of diabetes was significantly negatively correlated with self-efficacy (β = -0.23, P=0.03).

CONCLUSION

Arabic SEM6S is acceptable, reliable and repeatable metric for self-efficacy.

Impact of a supervised multicomponent physical exercise program on cognitive functions in patients with type 2 diabetes

This study evaluated the impact of a multicomponent exercise program on cognitive functions in participants with Type 2 Diabetes. Participants (n = 70, 65.6 ± 5.9 years) engaged in the program (75 min per session; 3 x week) for 32 weeks. A battery of cognitive tests was performed at baseline and study completion. Two groups were formed according to their attendance rate (low and high attendance), and statistical comparisons were computed on their changes in cognitive performance. Such changes were also associated with the attendance rate for all participants. Results showed no significant differences between groups in their change scores, although there were some within-group differences in both groups. Correlation analysis showed that the attendance rate was not associated with cognitive performance changes, except for one variable. As the exercise program did not improve cognitive function, we discuss the potential of future interventions to incorporate dual-task activities merging physical and cognitive stimulation.

Serum high-density lipoprotein cholesterol is a protective predictor of executive function in older patients with diabetes mellitus

AIMS/INTRODUCTION

Older people with diabetes mellitus are at high risk for cognitive impairment or dementia. The clinical predictors for cognitive decline in older people with diabetes mellitus were elucidated.

MATERIALS AND METHODS

This was a secondary analysis of a vitamin B12 intervention trial in older people with diabetes mellitus. A total of 271 non-demented individuals were followed up at 9-month intervals for 27 months. We explored the association between baseline clinical features with changes in cognitive measures (Clinical Dementia Rating scale, Neuropsychological Test Battery including executive function z-scores, psychomotor speed z-scores and memory z-scores).

RESULTS

A total of 152 participants had normal cognition (Clinical Dementia Rating 0) and 119 had cognitive impairment (Clinical Dementia Rating 0.5) at baseline. After 27 months, 41 participants had cognitive decline, 36 of whom were cognitively normal at baseline. Multiple logistic regression showed no significant clinical predictor of global cognitive decline. Higher high-density lipoprotein cholesterol (HDL-C) was associated with better executive performance at month 27 (β = 0.359, P < 0.001). Multilevel modeling showed that the highest tertile of HDL-C was associated with better executive function z-scores than the lowest tertile of HDL-C at all time-points.

CONCLUSIONS

Among older people with diabetes mellitus, higher serum HDL-C was associated with better executive function.

"Anxiety and Type 1 diabetes are like cousins": The experience of anxiety symptoms in youth with Type 1 diabetes

Type 1 diabetes (T1D) is one of the most common chronic health conditions in youth in the United States, and its incidence is rising worldwide. Youth with T1D are at a high risk of psychological comorbidity, for example, anxiety, depression, and eating disorders. Psychological comorbidities, especially anxiety symptoms, have been correlated with poorer diabetes outcomes, but anxiety symptoms have not been well studied in these youth. The primary aim of this study was to describe the experience of anxiety symptoms in youth with T1D, especially as those symptoms relate to diabetes self-management tasks. We used a qualitative descriptive approach, consisting of an in-depth, semi-structured interview comprising 10 open-ended questions with follow-up probes. The analysis was guided by the principles of thematic analysis. Demographic data, Hemoglobin A1c levels, and the State-Trait Anxiety Inventory for Children survey data were also collected and analyzed. We identified four themes and seven sub-themes. Participants (n = 29, ages 10-16, 55% female) reported that T1D was an extra layer of responsibility that took time away from their ability to participate fully in other aspects of their lives. Some participants were able to integrate diabetes management into their lives, while others were not. Some participants were dependent on parents and the school nurse for diabetes management. Participants described two types of anxiety symptoms, general and diabetes-specific, and they noted that their experience of anxiety was associated with poor quality sleep, general lifestyle factors, and diabetes.

Effect of a Diabetes Self-Efficacy Enhancing Program on Older Adults With Type 2 Diabetes: A Randomized Controlled Trial

This randomized controlled trial examined the effect of a diabetes self-efficacy enhancing program (DSEEP) on older adults with type 2 diabetes. The 8-week DSEEP consisted of a guidebook on diabetes self-care, a 1-day workshop, and fortnightly follow-up telephone calls. In total, 113 participants (56 in intervention group and 57 in control group) completed the study. Data were collected at baseline and at 8 weeks from the baseline. Outcome measures included self-efficacy, diabetes self-care activities, health-related quality of life, glycated hemoglobin (HbA1c) and unplanned health care service usage. Compared with participants in the control group, those who received DSEEP had significantly higher increase in self-efficacy and diabetes self-care activities, lower HbA1c, and lesser unplanned health service usage. However, there was no significant difference in health-related quality of life between the two groups. The DSEEP increased self-efficacy, which successfully enhanced self-care activities and reduced HbA1c.

Multiple Evidences for Association between Cognitive Impairment and Dysglycemia in Parkinson's Disease: Implications for Clinical Practice

Background and purpose: It remains unclear about the etiopathogenesis of cognitive impairment (CI) in Parkinson’s disease (PD). Since diabetes mellitus (DM) has been shown to be associated with CI in several diseases, we examined the association between CI and dysglycemia in PD.

Methods: Enrolled PD patients completed a series of clinical and neuropsychological assessments. Motor symptoms were determined by Hohen-Yahr staging (H-Y staging) and Unified Parkinson’s Disease Rating Scale – motor score (UPDRS-III). Neuropsychological functions were evaluated by the Mini Mental State Examination (MMSE), the Montreal Cognitive Assessment (MoCA), and the Hamilton Anxiety and Depression Scales. Moreover, fasting glucose, fasting insulin, glycosylated hemoglobin A1c (HbA1c) and oral glucose tolerance test were performed to assess glucose metabolism.

Results: MoCA and MMSE scores in PD patients with DM group (PD-DM) were significantly lower than those in PD patients without DM group (PD-nDM). Consistently, PD-DM group showed significantly higher constituent ratio of CI than PD-nDM group. In addition, MoCA scores in HbA1c ≥ 6.5% group and HbA1c ≥ 7% group were significantly lower than those in the corresponding control groups. MoCA score in IR ≥ 3 group was significantly lower than that in IR < 3 group. Furthermore, MoCA score was negatively correlated with H-Y staging, HbA1c and insulin resistance, respectively. Finally, regression analysis indicated that H-Y staging and HbA1c ≥ 7% were independent risk factors of CI in PD.

Conclusion: CI may be tightly associated with dysglycemia in, at least partially, PD patients. Importantly, H-Y staging and HbA1c ≥ 7%, two independent risk factors of CI in PD, may serve as key biomarkers in future PD clinical practice.

Diabetes Knowledge Among Adults with Serious Mental Illness and Comorbid Diabetes Mellitus

This study examined the association between psychiatric symptoms and diabetes knowledge (DK) among 90 adults with serious mental illness (SMI) and type 2 diabetes. The relationship between DK and glucose control (i.e., A1C) was also examined. In a hierarchical linear regression, greater negative symptom severity and lower cognitive functioning both predicted lower DK, though cognitive functioning superseded negative symptom severity when analyzed simultaneously. A Pearson correlation showed no significant relationship between DK and A1C. Although symptom severity and cognitive functioning are both related to DK among this population, cognitive functioning maybe particularly important.

Perceived cognitive deficits are associated with diabetes self-management in a multiethnic sample

Background

People with diabetes have almost twice the risk of developing cognitive impairment or dementia as do those without diabetes, and about half of older adults with diabetes will become functionally disabled or cognitively impaired. But diabetes requires complex self-management: patients must learn about the implications of their disease; manage their diets, physical activity, and medication; and monitor their blood glucose. Difficulties with cognition can hinder these activities.

Methods

The purpose of this study was to explore perceptions of cognitive ability in a multiethnic sample of persons with type 2 diabetes (T2DM). One hundred twenty participants completed surveys assessing perceived memory, executive function, diabetes self-management, and quality of life. Scores on the surveys were examined along with hemoglobin A1C levels and demographics.

Results

Scores for executive function were positively associated with self-reports of dietary adherence and blood glucose monitoring. Perceived memory ability was a significant predictor of quality of life, and executive function was a significant predictor of A1C.

Conclusions

Patients’ perceptions of their cognitive difficulties may assist health care providers in detection of patients’ deficiencies in performing diabetes self-management tasks. The relationships between cognitive difficulties and self-management found in this descriptive study suggest that research on the processes leading to cognitive changes in T2DM is needed, as are studies on how those processes affect diabetes self-management.

Incident Heart Failure and Cognitive Decline: The Atherosclerosis Risk in Communities Study

BACKGROUND

Cognitive impairment is found in a significant proportion of patients with heart failure (HF). Although cognitive impairment may be a consequence of HF, early signs of cognitive impairment may also indicate subclinical vascular disease, and thus a risk factor for future cardiovascular events.

METHODS AND RESULTS

The Atherosclerosis Risk in Communities Study is a prospective cohort study of the development of atherosclerosis. Cox proportional hazards regression was used to examine the association between mean 6-year change in cognitive function and incident HF in 7962 white and 1933 African-American men and women aged 46 to 70 years and free of clinical stroke. Scores were obtained for the Delayed Word Recall Test, the Digit Symbol Substitution Test (DSST), and the Word Fluency Test. There was a significantly increased risk of developing HF during the mean 12.6-year follow-up period after adjustment for age, gender, race, and education for those in the quartile with the greatest decline in DSST scores (hazard ratio [HR] = 1.17, P = .009), and in the quartile with the lowest baseline DSST scores (HR = 1.43, P < .001).

CONCLUSIONS

The results suggest that relatively low performance on a test of information processing speed may serve as an indicator of HF risk in middle age.

Self-care management programme for older adults with diabetes: An integrative literature review

This paper summarizes evidence on effectiveness of diabetes self-care interventions for older adults with diabetes, and identifies factors influencing self-care behaviours. The search for articles published from 2002 to 2012 was done using electronic databases, namely, MEDLINE, CINAHL, Scopus, PsycINFO and PubMed. Search terms include diabetes, self-management, self-care, barriers and intervention. Out of 261 articles screened, 21 were selected for review. Findings revealed that interventions using concepts of self-efficacy, self-determination and proactive coping, and interventions incorporating information technology were effective in influencing diabetes self-care behaviours with improved health outcomes. Psychosocial factors influencing self-care include motivation, socioeconomic status, literacy, knowledge, social and health-care providers' support, and particularly for older adults, the key factors were their self-efficacy, motor skill and literacy in self-care activities. This review provides important insight for nurse practitioners to address psychosocial issues in developing self-care management programmes for older adults with diabetes.

Effects of Longitudinal Glucose Exposure on Cognitive and Physical Function: Results from the Action for Health in Diabetes Movement and Memory Study

OBJECTIVES

To test whether average long-term glucose exposure is associated with cognitive and physical function in middle-aged and younger-old adults with type 2 diabetes mellitus.

DESIGN

Prospective cohort study.

SETTING

Data obtained as part of the Action for Health in Diabetes (Look AHEAD) trial (NCT00017953) and Look AHEAD Movement and Memory ancillary study (NCT01410097).

PARTICIPANTS

Overweight and obese individuals with type 2 diabetes mellitus aged 45 to 76 at baseline (N = 879).

MEASUREMENTS

Glycosylated hemoglobin (HbA1c) was measured at regular intervals over 7 years, and objective measures of cognitive function (Trail-Making Test, Modified Stroop Color-Word Test, Digit Symbol-Coding, Rey Auditory Verbal Learning Test, Modified Mini-Mental State Examination) and physical function (Short Physical Performance Battery, expanded Physical Performance Battery, 400-m and 20-m gait speed) and strength (grip and knee extensor strength) were assessed at the Year 8 or 9 follow-up examination.

RESULTS

Average HbA1c exposure was 7.0 ± 1.1% (53 ± 11.6 mmol/mol), with 57% of participants classified as having HbA1c levels of less than 7% (<53 mmol/mol), 27% having levels of 7% to 8% (53-64 mmol/mol), and 16% having levels of greater than 8% (>64 mmol/mol). After adjustment for age, sex, race, education, smoking status, alcohol intake, knee pain, physical fitness, body mass index, diabetes mellitus medication and statin use, ancillary year visit, and study arm and site, higher HbA1c was associated with worse physical but not cognitive function. Further adjustment for prevalent diabetes mellitus-related comorbidities made all associations nonsignificant. Results did not differ when stratified according to participant baseline age (<60 vs ≥ 60).

CONCLUSION

Results presented here suggest that, in the absence of diabetes mellitus-related complications, longitudinal glucose exposure is not associated with future cognitive and physical function. Optimal management of diabetes mellitus-related comorbidities may prevent or reduce the burden of disability associated with type 2 diabetes mellitus.

The influence of cognition on self-management of type 2 diabetes in older people

Diabetes is a growing public health issue, increasing in prevalence, eroding quality of life, and burdening health care systems. The complications of diabetes can be avoided or delayed by maintaining good glycemic control, which is achievable through self-management and, where necessary, medication. Older people with diabetes are at increased risk for cognitive impairment. This review aims to bring together current research that has investigated both cognition and diabetes self-management together. The Cumulative Index to Nursing and Allied Health (Cinahl), Excerpta Medica Database (Embase), Medical Literature Analysis and Retrieval System (Medline), and Psychological Information (PsychInfo) databases were searched. Studies were included if they featured older people with type 2 diabetes and had looked for associations between at least one distinct measure of cognition and at least one distinct measure of diabetes self-management. English language publications from the year 2000 were included. Cognitive measures of executive function, memory, and low scores on tests of global cognitive functioning showed significant correlations with multiple areas of diabetes self-management, including diabetes-specific numeracy ability, diabetes knowledge, insulin adjustment skills, ability to learn to perform insulin injections, worse adherence to medications, decreased frequency of self-care activities, missed appointments, decreased frequency of diabetes monitoring, and increased inaccuracies in reporting blood glucose monitoring. The nature of the subjects studied was quite variable in terms of their disease duration, previous medical histories, associated medical comorbidities, and educational level attained prior to being diagnosed with diabetes. The majority of studies were of an associational nature and not findings confirmed by repeat testing or by the effects of an intervention, neither were the majority of studies designed to give a view or conclusion on the clinical value or implications of the research. This only allows speculation of their importance. Most studies do not separate out the influence of aging itself in altering diabetes self-care behavior. We conclude that older people with type 2 diabetes are at increased risk for cognitive dysfunction. Changes in cognition may negatively affect diabetes self-management behaviors, influencing self-care outcomes. Age and depression may exacerbate any cognitive impairment.

Associations between Markers of Glucose and Insulin Function and Cognitive Function in Healthy African American Elders

BACKGROUND

Glucose and insulin are important moderators of cognitive function. African Americans have poorer glycemic control across the glycemic spectrum and are at increased risk for type 2 diabetes and poor cognitive health. It is unclear which glucoregulatory markers predict cognitive function in this at-risk population. The purpose of this study was to examine the association between cognitive function and common markers of glucoregulation in non-diabetic African Americans elders.

METHODS

Thirty-four, community-dwelling African Americans, aged 50-75 years completed cognitive testing and blood collection as part of a health screening assessment. Cognitive outcomes were composite scores derived from neuropsychological tests of executive function and verbal memory. Linear regression was used to examine relationships between cognitive composite scores and fasting blood levels of glucose, insulin, and hemoglobin A1C, with adjustments for age, education, body mass index, and antihypertensive medication use.

RESULTS

Fasting plasma glucose was negatively associated with executive function (β=-0.41, p=0.03). There was a trend of an association between fasting plasma glucose and verbal memory (β=-0.34, p=0.06). Fasting insulin and hemoglobin A1c were not associated with cognitive function.

CONCLUSION

High non-diabetic fasting glucose levels were associated with poorer executive function and verbal memory. These results provide preliminary support for proactive glucose control in older African Americans even before glycemic criteria for type 2 diabetes are met. Our findings suggests that high-normal FPG levels may represent an early red-flag to signify increased risk of cognitive impairment or decline.

Executive Function in Adults With Type 2 Diabetes: A Meta-Analytic Review

OBJECTIVE

To examine the extent to which Type 2 diabetes mellitus (T2DM) is associated with impairments in executive function (EF).

METHODS

Medline, PsychoInfo, and Scopus databases and published references were used to identify articles examining the association between T2DM status (case versus control) and EF decrements. Results from studies were converted to standardized mean differences and compared using random-effects models. Moderator analysis was conducted for age, sex, and diabetes duration using maximum likelihood estimation.

RESULTS

Sixty studies (59 articles) including 9815 individuals with T2DM and 69,254 controls were included. Findings indicated a small but reliable association between T2DM status and EF decrements (d = -0.248, p < .001), observed across all aspects of EF examined: verbal fluency, mental flexibility, inhibition, working memory, and attention. Disease duration significantly moderated the effect of T2DM status on EF.

CONCLUSIONS

T2DM is associated with a mild-to-moderate EF decrements. Such decrements are stronger among those with shorter disease duration.

An item response theory analysis of the Executive Interview and development of the EXIT8: A Project FRONTIER Study

INTRODUCTION

The Executive Interview (EXIT25) is an effective measure of executive dysfunction, but may be inefficient due to the time it takes to complete 25 interview-based items. The current study aimed to examine psychometric properties of the EXIT25, with a specific focus on determining whether a briefer version of the measure could comprehensively assess executive dysfunction.

METHOD

The current study applied a graded response model (a type of item response theory model for polytomous categorical data) to identify items that were most closely related to the underlying construct of executive functioning and best discriminated between varying levels of executive functioning. Participants were 660 adults ages 40 to 96 years living in West Texas, who were recruited through an ongoing epidemiological study of rural health and aging, called Project FRONTIER. The EXIT25 was the primary measure examined. Participants also completed the Trail Making Test and Controlled Oral Word Association Test, among other measures, to examine the convergent validity of a brief form of the EXIT25.

RESULTS

Eight items were identified that provided the majority of the information about the underlying construct of executive functioning; total scores on these items were associated with total scores on other measures of executive functioning and were able to differentiate between cognitively healthy, mildly cognitively impaired, and demented participants. In addition, cutoff scores were recommended based on sensitivity and specificity of scores.

CONCLUSION

A brief, eight-item version of the EXIT25 may be an effective and efficient screening for executive dysfunction among older adults.

The influence of subclinical cardiovascular disease and related risk factors on cognition in type 2 diabetes mellitus: The DHS-Mind study

We hypothesized that measures of coronary artery calcified plaque (CAC) collected at baseline from the Diabetes Heart Study (DHS) would explain associations between cognition and diabetes collected at follow-up approximately 7 years later. The DHS is a sibling study of cardiovascular disease (CVD) in a cohort with a high prevalence of type 2 diabetes (~80%). Associations between baseline CAC and cognitive performance were tested using generalized estimating equations and mixed effects models to adjust for familial relationships. Diabetes status was associated (p<0.05) with poorer performance on tests of verbal memory, processing speed, and semantic fluency adjusting for age, sex, education, and hypertension status. As hypothesized, including CAC in the statistical model attenuated this association. Additionally, CAC and fasting glucose predicted performance in tasks not associated with diabetes status in this study (Stroop Task, Phonemic Fluency). These results confirm work attributing the heterogeneity of cognitive outcomes in type 2 diabetes to subclinical risk factors that combine to affect different aspects of brain function. Importantly, these results imply that risk factor intervention should begin before comorbidities, particularly CVD, become clinically apparent.

Diabetes, glucose control, and 9-year cognitive decline among older adults without dementia

OBJECTIVES

To determine if prevalent and incident diabetes mellitus (DM) increase risk of cognitive decline and if, among elderly adults with DM, poor glucose control is related to worse cognitive performance. DESIGN Prospective cohort study.

SETTING

Health, Aging, and Body Composition Study at 2 community clinics.

PARTICIPANTS

A total of 3069 elderly adults (mean age, 74.2 years; 42% black; 52% female).

MAIN OUTCOME MEASURES

Participants completed the Modified Mini-Mental State Examination (3MS) and Digit Symbol Substitution Test (DSST) at baseline and selected intervals over 10 years. Diabetes mellitus status was determined at baseline and during follow-up visits. Glycosylated hemoglobin A1c level was measured at years 1 (baseline), 4, 6, and 10 from fasting whole blood.

RESULTS

At baseline, 717 participants (23.4%) had prevalent DM and 2352 (76.6%) were without DM, 159 of whom developed incident DM during follow-up. Participants with prevalent DM had lower baseline test scores than participants without DM (3MS: 88.8 vs 90.9; DSST: 32.5 vs 36.3, respectively; t = 6.09; P = .001 for both tests). Results from mixed-effects models showed a similar pattern for 9-year decline (3MS: -6.0- vs -4.5-point decline; t = 2.66; P = .008; DSST: -7.9- vs -5.7-point decline; t = 3.69; P = .001, respectively). Participants with incident DM tended to have baseline and 9-year decline scores between the other 2 groups but were not statistically different from the group without DM. Multivariate adjustment for demographics and medical comorbidities produced similar results. Among participants with prevalent DM, glycosylated hemoglobin A1c level was associated with lower average mean cognitive scores (3MS: F = 8.2; P for overall = .003; DSST: F = 3.4; P for overall = .04), even after multivariate adjustment.

CONCLUSION

Among well-functioning older adults, DM and poor glucose control among those with DM are associated with worse cognitive function and greater decline. This suggests that severity of DM may contribute to accelerated cognitive aging.

Which aspects of executive dysfunction influence ability to manage diabetes in older adults?

AIMS

To examine whether different aspects of executive function as measured by different assessment tools are associated with glycaemic control and other clinical characteristics in older adults with Type 2 diabetes.

METHODS

We performed a cross-sectional study of older adults aged ≥ 70 years with Type 2 diabetes at a tertiary care diabetes centre. The Dysexecutive Questionnaire was used to measure self-reported executive dysfunction. Objective tests of executive functions included a modified clock drawing test (Clock-in-a-Box), Trail Making Tests (parts A and B) and verbal fluency. Demographic and clinical information was collected using questionnaires and surveys. Glycaemic control was measured by HbA(1c).

RESULTS

We evaluated 145 patients [average age 77 ± 5 years, diabetes duration 15 ± 11 years, mean HbA(1c) 56 ± 11 mmol/mol (7.3 ± 1.1%)]. Poor performances on objective tests (low scores on Clock-in-a-Box and verbal fluency; and high scores on Trail Making Tests A and B) but not on the subjective test (the Dysexecutive Questionnaire), were associated with poor glycaemic control (r = -0.23, P < 0.005; r = -0.17, P < 0.04; r = 0.20, P < 0.01, r = 0.22, P < 0.008, r = -0.07, P < 0.42, respectively). In a multiple regression model (r(2) = 0.39), high Dysexecutive Questionnaire scores were associated with higher diabetes-related distress (P < 0.0004), depressive symptoms (P < 0.004), number of falls (P < 0.009), fear of falling (P < 0.01), less years of education (P < 0.0007) and fewer medications (P < 0.001).

CONCLUSIONS

On the one hand, in older adults, executive dysfunction detected by objective tests is associated with poor glycaemic control and may be considered before prescribing complex treatment regimens. On the other hand, self-reported executive dysfunction is associated with risk and fear of falls, and more affective symptoms, which may indicate higher awareness of subtle deficits.

Choosing targets for glycaemia, blood pressure and low-density lipoprotein cholesterol in elderly individuals with diabetes mellitus

Diabetes mellitus in the 'elderly' poses unique management challenges that contribute to conflicting priorities. Individualized management requires taking into account each patient's medical history, functional ability, home care situation, life expectancy and his/her health beliefs; individuals value trade-offs (e.g. quantity versus quality of life, and side effects as well as risks versus long-term benefits) differently. Moreover, this decision making relies on imperfect evidence. Target goals for three intermediate outcomes - glycaemic control (glycosylated haemoglobin [HbA(1c)]), blood pressure control and lipid control (low-density lipoprotein cholesterol [LDL-C]) - help keep management on track. Of these, glycaemic control is usually the most complex. Glycaemic control alleviates symptoms of hyperglycaemia and can improve micro- and macrovascular outcomes. Tight glycaemic control (HbA(1c) <7%) clearly improves microvascular outcomes. However, hypoglycaemia and polypharmacy are the main drawbacks of tight control. Factors that influence the benefits and drawbacks include age, longevity and co-morbidities, including the geriatric 'syndromes' of frailty and falls. We favour the explicit risk-stratified approach of the Department of Veterans Affairs/Department of Defense (VA/DoD) guidelines, which set HbA(1c) target ranges based on physiological age or the presence/severity of major co-morbidities and microvascular complications. There are clear benefits of blood pressure and cholesterol control (primarily reduction of macrovascular events, but also microvascular events), and their overall cost effectiveness exceeds that of glycaemic control. Issues with treatment for hypertension include potential side effects of drugs, a potential increased risk of falls and risks of polypharmacy. Nevertheless, the evidence for a blood pressure target of <140/80 mmHg is reasonably strong if it can be achieved safely. In general, we recommend use of an HMG-CoA reductase inhibitor (statin) and an LDL-C target of <100 mg/dL, especially if an individual cannot tolerate a moderate dose of a statin.

Neuropsychological benefits of stationary bike exercise and a cybercycle exergame for older adults with diabetes: an exploratory analysis

OBJECTIVE

This quasi-experimental exploratory study investigated neuropsychological effects of exercise among older adults with diabetes mellitus (DM) compared with adults without diabetes (non-DM), and it examined the feasibility of using a stationary bike exergame as a form of exercise for older adults with and without diabetes. It is a secondary analysis that uses a small dataset from a larger randomized clinical trial (RCT) called the Cybercycle Study, which compared cognitive and physiological effects of traditional stationary cycling versus cybercycling.

METHODS

In the RCT and the secondary analysis, older adults living in eight independent living retirement facilities in the state of New York were enrolled in the study and assigned to exercise five times per week for 45 min per session (two times per week was considered acceptable for retention in the study) by using a stationary bicycle over the course of 3 months. They were randomly assigned to use either a standard stationary bicycle or a "cybercycle" with a video screen that displayed virtual terrains, virtual tours, and racing games with virtual competitors. For this secondary analysis, participants in the RCT who had type 2 DM (n = 10) were compared with age-matched non-DM exercisers (n = 10). The relationship between exercise and executive function (i.e., Color Trials 2, Digit Span Backwards, and Stroop C tests) was examined for DM and non-DM patients.

RESULTS

Older adults with and without diabetes were able to use cybercycles successfully and complete the study, so the feasibility of this form of exercise for this population was supported. However, in contrast with the larger RCT, this small subset did not demonstrate statistically significant differences in executive function between the participants who used cybercycles and those who used stationary bikes with no games or virtual content on a video screen. Therefore, the study combined the two groups and called them "exercisers" and compared cognitive outcomes for DM versus non-DM patients. As predicted, exercisers with DM exhibited significant gains in executive function as measured by the Color Trails 2 test, controlling for age and education, while non-DM exercisers did not significantly gain in this measure [group × time interaction, F(1,16]) = 9.75; p = .007].

CONCLUSIONS

These preliminary results support the growing literature that finds that exercise may improve cognition among older adult with DM. Additional research is needed to clarify why certain aspects of executive function might be differentially affected. The current findings may encourage physicians to prescribe exercise for diabetes management and may help motivate DM patients' compliance for engaging in physical activity.

Specific cognitive abilities are associated with diabetes self-management behavior among patients with type 2 diabetes

AIM

Patients with diabetes differ in compliance to diabetes self-management which influences their long-term health. Psychological factors, namely depression and cognitive abilities, are associated with diabetes self-management behavior. The aim of the study was to identify independent association of particular cognitive functions with diabetes self-management.

METHODS

In a cross sectional study 98 adults with type 2 diabetes attending Diabetes Outpatient Clinic were examined using the measures of diabetes self-management (Summary of Diabetes Self-Care Activities (SDSCA) measure), depression (Hamilton Depression Inventory (HDI)), diabetes distress (Problem Areas In Diabetes scale (PAID)), and the neuropsychological battery of tests for assessment of cognitive functions. Sociodemographic and diabetes-related data were collected. Univariate and multivariate regression analyses were used to identify and evaluate the predictors of diabetes self-management.

RESULTS

Specific cognitive functions, namely immediate memory, visuospatial/constructional abilities, attention, and specific executive functions (planning and problem solving) were significantly associated with diabetes self-management. Among cognitive factors, planning and problem solving abilities were strongest predictors; furthermore, in a multivariate regression their association was independent from depression.

CONCLUSIONS

Specific cognitive abilities, particularly planning and problem solving, play an independent role in diabetes self-management behaviors. Assessing patients' cognitive abilities may be of value for adjusting self-management education and treatment regimen.

Association of metabolic dysregulation with volumetric brain magnetic resonance imaging and cognitive markers of subclinical brain aging in middle-aged adults: the Framingham Offspring Study

OBJECTIVE

Diabetic and prediabtic states, including insulin resistance, fasting hyperglycemia, and hyperinsulinemia, are associated with metabolic dysregulation. These components have been individually linked to increased risks of cognitive decline and Alzheimer's disease. We aimed to comprehensively relate all of the components of metabolic dysregulation to cognitive function and brain magnetic resonance imaging (MRI) in middle-aged adults.

RESEARCH DESIGN AND METHODS

Framingham Offspring participants who underwent volumetric MRI and detailed cognitive testing and were free of clinical stroke and dementia during examination 7 (1998-2001) constituted our study sample (n = 2,439; 1,311 women; age 61 ± 9 years). We related diabetes, homeostasis model assessment of insulin resistance (HOMA-IR), fasting insulin, and glycohemoglobin levels to cross-sectional MRI measures of total cerebral brain volume (TCBV) and hippocampal volume and to verbal and visuospatial memory and executive function. We serially adjusted for age, sex, and education alone (model A), additionally for other vascular risk factors (model B), and finally, with the inclusion of apolipoprotein E-ε4, plasma homocysteine, C-reactive protein, and interleukin-6 (model C).

RESULTS

We observed an inverse association between all indices of metabolic dysfunction and TCBV in all models (P < 0.030). The observed difference in TCBV between participants with and without diabetes was equivalent to approximately 6 years of chronologic aging. Diabetes and elevated glycohemoglobin, HOMA-IR, and fasting insulin were related to poorer executive function scores (P < 0.038), whereas only HOMA-IR and fasting insulin were inversely related to visuospatial memory (P < 0.007).

CONCLUSIONS

Metabolic dysregulation, especially insulin resistance, was associated with lower brain volumes and executive function in a large, relatively healthy, middle-aged, community-based cohort.