Peri-Operative Risk Factors Associated with Post-Operative Cognitive Dysfunction (POCD): An Umbrella Review of Meta-Analyses of Observational Studies.

This umbrella review aimed to systematically identify the peri-operative risk factors associated with post-operative cognitive dysfunction (POCD) using meta-analyses of observational studies. To date, no review has synthesised nor assessed the strength of the available evidence examining risk factors for POCD. Database searches from journal inception to December 2022 consisted of systematic reviews with meta-analyses that included observational studies examining pre-, intra- and post-operative risk factors for POCD. A total of 330 papers were initially screened. Eleven meta-analyses were included in this umbrella review, which consisted of 73 risk factors in a total population of 67,622 participants. Most pertained to pre-operative risk factors (74%) that were predominantly examined using prospective designs and in cardiac-related surgeries (71%). Overall, 31 of the 73 factors (42%) were associated with a higher risk of POCD. However, there was no convincing (class I) or highly suggestive (class II) evidence for associations between risk factors and POCD, and suggestive evidence (class III) was limited to two risk factors (pre-operative age and pre-operative diabetes). Given that the overall strength of the evidence is limited, further large-scale studies that examine risk factors across various surgery types are recommended.

Effect of lean red meat combined with a multicomponent exercise program on muscle and cognitive function in older adults: a 6-month randomized controlled trial.

BACKGROUND: Exercise and increased dietary protein have been linked to improved muscle and cognitive health, but the combination may be more effective. OBJECTIVE: In this study performed in community-dwelling older adults undergoing a 3-d/wk resistance-based exercise training program, we investigated whether those who consumed lean red meat compared to carbohydrates on the 3 training days per wk would experience greater exercise-induced improvements in total body and leg lean mass (LM), muscle strength, and executive function (multiple primary outcomes), as well as muscle size and density, functional performance, cognition, inflammatory and neurotrophic markers, blood pressure, and lipid concentrations. DESIGN: In a 24-wk, 2-arm parallel randomized controlled trial, 154 adults aged ≥65 y participated in a multicomponent 3-d/wk resistance-based exercise program with random allocation to either a lean red meat group (two 80-g servings of cooked red meat), the exercise plus lean red meat (Ex + Meat) group (n = 77) or a control group receiving carbohydrates in the form of one-half cup (approximately 225 g cooked weight) of rice or pasta or 1 medium potato, the exercise plus carbohydrate control (C + Ex) group (n = 77), on the training days. RESULTS: Exercise-induced improvements (mean within group changes) did not significantly differ between groups for the primary outcomes of total body LM (0.6 to 0.8 kg), leg LM (0.1 to 0.2 kg), thigh muscle cross-sectional area (3.7% to 4.9%), leg and back muscle strength (26% to 40%), and executive function (z-score SD: 0.33 to 0.39), nor the secondary outcomes of global cognition function (0.17 to 0.23 SD), fat mass (-0.65 to -0.75 kg), physical function measures (sit-to-stand, both 15%; 4-square step test, 2% to 7%), or systolic blood pressure (-3.2 to -4.1 mm Hg). The Ex + Meat group experienced greater improvements than the C + Ex in arm LM (0.07 kg; 95% CI: 0.01, 0.14; P = 0.029), gait speed (0.05 m/s; 95% CI: 0.00, 0.11; P = 0.042), muscle density (1.0%; 95% CI: 0.2, 1.9; P = 0.015), and appendicular LM in the per-protocol analysis (0.21 kg; 95% CI: 0.02, 0.40; P = 0.03). The C + Ex group had greater net improvements in working memory/learning after 12 wk (SD: 0.24; 95% CI: 0.05, 0.43; P = 0.011) and 24 wk (SD: 0.27; 95% CI: 0.06, 0.49; P = 0.007). Inflammatory and neurotrophic markers did not change in either group. CONCLUSION: In healthy community-dwelling older adults undertaking resistance-based exercise training 3-d/wk, participants who consumed lean red meat in line with current Australian dietary recommendations did not experience any significant additional benefits in the primary outcome measures of muscle mass, strength, or cognitive function compared to participants consuming carbohydrates.This trial is registered with the Australian and New Zealand Clinical Trials Registry as ACTRN12613001153707.

Greater Circulating Copper Concentrations and Copper/Zinc Ratios are Associated with Lower Psychological Distress, But Not Cognitive Performance, in a Sample of Australian Older Adults.

Dyshomeostasis of copper and zinc is linked to neurodegeneration. This study investigated the relationship between circulating copper and zinc and copper/zinc ratios and cognitive function, symptoms of depression and anxiety, and neurotrophic factors in older Australian adults. In this cross-sectional study (n = 139), plasma copper, serum zinc, and neurotrophic factors (brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor, and insulin-like growth factor-1) were assessed. Cognition was assessed using the Cogstate battery and the Behavior Rating Inventory (BRI) of Executive Function (Adult version). Symptoms of anxiety and depression were assessed with the Hospital Anxiety and Depression Scale. Copper (ß = -0.024; 95% CI = -0.044, -0.004; p = 0.019) and copper/zinc ratio (ß = -1.99; 95% CI = -3.41, -0.57; p = 0.006) were associated with lower depressive symptoms, but not cognition. Plasma copper had a modest positive association with BDNF (ß = -0.004; 95% CI = 0.000, 0.007; p = 0.021). Zinc was not associated with any of the outcomes. In conclusion, greater circulating copper concentrations and higher copper/zinc ratios were associated with lower depressive symptoms (but not cognition), with copper also positively associated with BDNF concentration, in a sample of community-dwelling older adults.

Selenium Status Is Not Associated with Cognitive Performance: A Cross-Sectional Study in 154 Older Australian Adults.

Selenium was suggested to play a role in modulating cognitive performance and dementia risk. Thus, this study aimed to investigate the association between selenium status and cognitive performance, as well as inflammatory and neurotrophic markers in healthy older adults. This cross-sectional study included 154 older adults (≥60 years) from Victoria, Australia. Participants were assessed for cognitive performance (Cogstate battery), dietary selenium intake (two 24-h food recalls), plasma selenium concentration, inflammatory markers (interleukin (IL)-6, -8, -10, tumor necrosis factor-alpha and adiponectin) and neurotrophic factors (brain-derived neurotrophic factor, vascular endothelial growth factor and insulin-like growth factor 1). Dietary selenium intake was adequate for 85% of all participants. The prevalence of selenium deficiency was low; only 8.4% did not have the minimum concentration in plasma required for optimization of iodothyronine 5' deiodinases activity. Multiple linear regression analysis revealed that plasma selenium was not associated with cognitive performance, inflammatory markers nor neurotrophic factors, independent of age, sex, body mass index (BMI), habitual physical activity, APOE status, education, and history of cardiovascular disease. The lack of association might be due to the optimization of selenoproteins synthesis as a result of adequate selenium intake. Future prospective studies are recommended to explore potential associations of selenium status with age-associated cognitive decline.

Brain functional alterations in Type 2 Diabetes - A systematic review of fMRI studies.

Type 2 Diabetes (T2DM) is emerging as a major global health issue. T2DM can adversely affect cognition and increase dementia risk. This systematic review aimed to examine the functional brain changes that may underlie cognitive dysfunction in adults with T2DM. Studies were restricted to those which used functional magnetic resonance imaging (fMRI). Nineteen independent studies were identified, mostly comprised of middle aged or older adults. Resting-state studies demonstrated that compared to controls, connectivity of the Default Mode Network (DMN) was reduced and the majority of task-based studies identified reduced activation in T2DM patients in regions relevant to task performance. Abnormalities of low frequency spontaneous brain activity were observed, particularly in visual regions. As most studies demonstrated that alterations in fMRI were related to poorer neuropsychological task performance, these results indicate that functional brain abnormalities in T2DM have consequences for cognition.