Search

The prevalence of type 2 diabetes (T2D) and cognitive dysfunction increases with age. As society ages, clinicians will be increasingly tasked with managing older people who have both T2D and cognitive dysfunction. T2D is associated with an increased risk of cognitive dysfunction and hence there is increasing interest in whether T2D is a causal factor in the pathogenesis of cognitive decline and dementia. Recent advances in the use of sensitive measures of in vivo brain dysfunction in life-course studies can help understand potential mechanistic pathways and also help guide recommendations for clinical practice. In this article we will describe new horizons in the understanding of cognitive dysfunction associated with T2D. Coming from a clinical perspective, we discuss potential mechanisms and pathways linking the 2 conditions and the contribution of multimodal neuroimaging and study designs to advancing understanding in the field. We also highlight the important issues on the horizon that will need addressing in clinical identification, management, and risk reduction for people with coexistent T2D and cognitive dysfunction., (© The Author(s) 2021. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objectives: Poor health literacy (HL) is associated with poorer health outcomes in diabetes but little is known about its effects on foot disease. This study was aimed to determine the associations between HL and diabetic foot disease., Design: This is a cross-sectional analysis of baseline data from a prospective study of foot disease., Setting: Attendees of the Royal Hobart Hospital's Diabetes outpatient clinics., Participants: 222 people with type 1 or type 2 diabetes aged >40 years and without a history of foot disease, psychotic disorders or dementia., Measures: Outcomes were peripheral neuropathy, peripheral arterial disease and foot deformity according to published guidelines. The exposure, HL, was measured using the short form Test of Functional Health Literacy in Adults (S-TOFHLA) and the Health Literacy Questionnaire (HLQ). Covariates included demographic characteristics, medical history, psychological measures and foot care behaviour., Results: Of 222 participants, 204 had adequate HL. (Mean (SD) S-TOFHLA scores were 31.9 (6.7)), mean(SD) HLQ scores were 134.4 (18.4)). In univariable but not multivariable analyses, higher S-TOFHLA scores were associated with lower overall risk for foot disease (OR 0.96, 95% CI 0.93 to 0.99) and loss of protective sensation (OR 0.95, 95% CI 0.91 to 0.995)., Conclusions: These data provide little support for clinically important impacts of HL on risk factors for diabetic foot disease. However, in the absence of longitudinal data, such effects cannot be ruled out. Longitudinal studies measuring incident foot disease are needed to properly judge the potential for interventions improving HL to reduce the incidence of diabetic foot disease., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: To study longitudinal relationships between type 2 diabetes mellitus (T2DM), cortical thickness, and cognitive function in older people with normal cognition, mild cognitive impairment, and Alzheimer disease (AD)., Methods: The sample was derived from the Alzheimer's Disease Neuroimaging Initiative cohort who underwent brain MRI and cognitive tests annually for 5 years. Presence of T2DM was based on fasting blood glucose ≥7.0mml/L or the use of glucose-lowering agents. We used latent growth curve modeling to explore longitudinal relationships between T2DM, cortical thickness, and cognitive function, adjusting for relevant covariates and testing for interactions., Results: There were 124 people with T2DM (mean age 75.5 years, SD 6.2) and 693 without T2DM (mean age 75.1 years, SD 6.9) with at least 1 MRI available. AD and lower cortical thickness at study entry was associated with a lower chance of having a MRI available at each follow-up phase (all p < 0.001). T2DM was associated with lower baseline cortical thickness ( p = 0.01). We found no direct effect of T2DM on decline in cortical thickness or cognitive function, but there was an indirect pathway linking T2DM and cognitive decline via baseline cortical thickness (β = -0.17, p = 0.022). There was an interaction between T2DM and education whereby the negative effect of T2DM on baseline cortical thickness was reduced in those with greater education (β = 0.34, p = 0.037). These associations changed minimally when adjusted for baseline cognitive diagnosis., Conclusions: In an older cohort with low cerebrovascular disease burden, T2DM contributes to cognitive decline via neurodegeneration. Prior brain and cognitive reserve may protect against this effect., (© 2019 American Academy of Neurology.)

Background: Type 2 Diabetes (T2D) is associated with increased risk of dementia. We aimed to determine the feasibility of a randomised controlled trial (RCT) examining the efficacy of exercise on cognition and brain structure in people with T2D., Methods: A 6-month pilot parallel RCT of a progressive aerobic- and resistance-training program versus a gentle movement control group in people with T2D aged 50-75 years (n = 50) at the University of Tasmania, Australia. Assessors were blinded to group allocation. Brain volume (total, white matter, hippocampus), cortical thickness and white matter microstructure (fractional anisotrophy and mean diffusivity) were measured using magnetic resonance imaging, and cognition using a battery of neuropsychological tests. Study design was assessed by any changes (during the pilot or recommended) to the protocol, recruitment by numbers screened and time to enrol 50 participants; randomisation by similarity of characteristics in groups at baseline, adherence by exercise class attendance; safety by number and description of adverse events and retention by numbers withdrawn., Results: The mean age of participants was 66.2 (SD 4.9) years and 48% were women. There were no changes to the design during the study. A total of 114 people were screened for eligibility, with 50 participants with T2D enrolled over 8 months. Forty-seven participants (94%) completed the study (23 of 24 controls; 24 of 26 in the intervention group). Baseline characteristics were reasonably balanced between groups. Exercise class attendance was 79% for the intervention and 75% for the control group. There were 6 serious adverse events assessed as not or unlikely to be due to the intervention. Effect sizes for each outcome variable are provided., Conclusion: This study supports the feasibility of a large scale RCT to test the benefits of multi-modal exercise to prevent cognitive decline in people with T2D. Design changes to the future trial are provided., Trial Registration: ANZCTR 12614000222640 ; Registered 3/3/2014; First participant enrolled 26/6/2014, study screening commenced 1/9/2014; Australian and New Zealand Clinical Trial Registry.

Cognitive impairment and dementia are common contributors to institutionalization and loss of quality of life in older people. Both type 2 diabetes mellitus (T2DM) and physical inactivity are prevalent and important modifiable risk factors for developing dementia. Physical activity is recommended in the management of T2DM, and there is growing evidence that exercise, a subgroup of physical activity, is also beneficial for maintaining and improving brain structure and function. This paper reviews the evidence for a benefit of exercise on T2DM related cognitive impairment and dementia. In addition, the type (e.g., aerobic, resistance), intensity, duration, and frequency of exercise are discussed. This review shows that although exercise has known benefits on the mechanisms linking T2DM to dementia, there are very few randomized controlled trials examining whether this is the case. It is concluded that the uptake of exercise for the brain has great potential to improve quality of life and provide significant cost savings, but further research is warranted to clarify the effects of exercise on T2DM and those on dementia.

Background: Physical activity (PA) is important in managing Type 2 Diabetes Mellitus (T2DM). This study aimed to determine 1) the number of daily steps taken by older people with T2DM, 2) if T2DM is associated with taking fewer steps per day and less likelihood of meeting PA guidelines, and 3) whether these associations are modified by age or gender., Methods: PA was obtained by pedometer from 2 cohorts of older adults with and without T2DM. Multivariable regression was used to determine associations between T2DM, mean steps per day and meeting a guideline equivalent (7 100 steps per day)., Results: There were 293 participants with T2DM (mean age 67.6 ± 6.8 years) and 336 without T2DM (mean age 72.1 ± 7.1 years). In women, T2DM was associated with fewer mean steps per day (β = -1306.4; 95% CI -2052.5, -560.3; P = .001) and not meeting the PA guidelines (OR 0.51; 95% CI 0.28, 0.92; P = .03). Associations were not significant in men (P > .05). Only 29.7% of those with T2DM and 33.3% of those without T2DM met PA guidelines., Conclusions: Greater focus is needed on how to maintain and increase PA in older age with particular focus on women with T2DM.

Aim: Type 2 diabetes mellitus (T2D) is associated with gray matter atrophy. Adiposity and physical inactivity are risk factors for T2D and brain atrophy. We studied whether the associations of T2D with total gray matter volume (GMV) and hippocampal volume (HV) are dependent on obesity and physical activity., Materials and Methods: In this cross-sectional study, we measured waist-hip ratio (WHR), body mass index (BMI), mean steps/day and brain volumes in a community dwelling cohort of people with and without T2D. Using multivariable linear regression, we examined whether WHR, BMI and physical activity mediated or modified the association between T2D, GMV and HV., Results: There were 258 participants with (mean age 67 ± 7 years) and 302 without (mean age 72 ± 7 years) T2D. Adjusting for age, sex and intracranial volume, T2D was independently associated with lower total GMV (p = 0.001) and HV (p<0.001), greater WHR (p<0.001) and BMI (p<0.001), and lower mean steps/day (p = 0.002). After adjusting for covariates, the inclusion of BMI and mean steps/day did not significantly affect the T2D-GMV association, but WHR attenuated it by 32% while remaining independently associated with lower GMV (p<0.01). The T2D-HV association was minimally changed by the addition of BMI, steps/day or WHR in the model. No statistical interactions were observed between T2D and measures of obesity and physical activity in explaining brain volumes., Conclusions: Abdominal obesity or its downstream effects may partially mediate the adverse effect of T2D on brain atrophy. This requires confirmation in longitudinal studies.