Waist circumference is correlated with poorer cognition in elderly type 2 diabetes women

Associations of dynapenic abdominal obesity and its components with cognitive impairment among hemodialysis patients

OBJECTIVE

Cognitive impairment (CI) is a prevalent and significant health concern among patients undergoing maintenance hemodialysis (MHD). Recent studies have highlighted the growing interest in dynapenic abdominal obesity (DAO), which combines both low muscle strength and excess abdominal fat. Despite the increasing recognition of DAO, its association with CI in MHD patients remains uncertain. The objective of this study was to investigate the relationship between DAO and CI in MHD patients.

METHODS

We conducted a multicenter, cross-sectional study in twenty dialysis centers, encompassing 3767 adult MHD patients. Participants were categorized into four distinct groups based on the criteria for abdominal obesity (AO), defined as waist circumference (WC) ≥ 90 cm for men and ≥ 85 cm for women, and dynapenia, characterized by handgrip strength (HGS) < 28 kg in men and < 18 kg in women. The groups were: non-dynapenic/non-abdominal obesity (NDNAO), non-dynapenic/abdominal obesity (NDAO), dynapenic/non-abdominal obesity (DNAO), and dynapenic/abdominal obesity (DAO). Cognitive function was assessed using the Mini-Mental State Examination (MMSE), with a score below 27 indicating cognitive impairment (CI). Multivariate logistic models were used to investigate the correlations between DAO and its components with the risk of CI. Smooth curve fittings were used to identify the potential nonlinear relationship between WC and the MMSE scores. The piecewise regression model was used for fitting while the log-likelihood ratio test was used to determine whether a significant inflection point existed. Additionally, we conducted a series of subgroup analyses to test the robustness of our results.

RESULTS

The multi-variable adjusted odds ratios (ORs) of CI for DNAO and DAO were 2.10 (1.68-2.62, P < 0.001) and 1.81 (1.40-2.33, P < 0.001), respectively. These findings were consistently observed across subgroup analyses, indicating robustness in our results. AO was associated with increased risk of CI in the crude model (OR 1.22, 95%CI 1.05-1.41; P = 0.008), however, it became a protective factor after adjusting for potential confounders (OR 0.84, 95%CI 0.71-0.98; P = 0.03). We identified a significant nonlinear relationship between WC, HGS, and MMSE scores (P for non-linearity < 0.05). Notably, an inflection point at 23.29 kg for HGS was determined through threshold effect analysis. Below a WC threshold of 101 cm, MMSE scores demonstrated a positive correlation with WC (β = 0.03, 95% CI 0.01-0.04, P < 0.001). However, this relationship did not achieve statistical significance for WC values above 101 cm.

CONCLUSIONS

Both DAO and DNAO are associated with increased odds of CI in MHD patients, with dynapenia being the major factor contributing to the increased odds of CI, while AO appears to play a protective role against CI.

The mediating role of body surface area-adjusted basal metabolic rate: effects of low muscle mass and central obesity on cognitive impairment in Chinese patients with type 2 diabetes mellitus

Background

This study investigates the relationship between basal metabolic rate (BMR), body composition, obesity indices, and cognitive impairment (CI) in middle-aged and older type 2 diabetes mellitus (T2DM) patients, assessing their potential role in CI screening.

Methods

A cross-sectional study included 1243 T2DM patients over 45 years old. CI was assessed using the Montreal Cognitive Assessment. BMR and body composition indices were measured through bioelectrical impedance analysis. The associations and predictions related to CI were explored using multivariable-adjusted logistic regression, restricted cubic spline (RCS) models, and receiver operating characteristic (ROC) curve analyses. Mediation analysis explored the role of BMR adjusted by body surface area (BMR/BSA) in CI risk.

Results

Patients with CI showed significantly lower BMR, BMR adjusted for height squared (BMR/Height²), BMR/BSA, appendicular skeletal muscle mass (ASM), and fat-free mass (FFM), alongside higher waist circumference (WC) and percentage of body fat. Logistic regression showed that participants in the fourth quartile of BMR, BMR/Height2, and BMR/BSA had approximately a 54% reduced risk of CI (odds ratio range 0.457 to 0.463). RCS analysis indicated a linear decrease in CI risk with increasing BMR metrics. ROC analysis indicated high predictive efficacy for CI with combined indicators, particularly BMR and FFM (area under the curve 0.645). Mediation analysis suggested that BMR/BSA played a significant mediating role in WC, ASM and FFM on CI risk, with a mediation proportion ranging from 45.73% to 50.87%.

Conclusion

Low energy expenditure assessed by BMR/BSA is an independent risk factor for increased CI risk in middle-aged and elderly T2DM patients. Central obesity, low muscle mass, and low energy expenditure significantly elevate CI risk in this population.

Body Composition, Sarcopenic Obesity, and Cognitive Function in Older Adults: Findings From the National Health and Nutrition Examination Survey (NHANES) 1999-2002 and 2011-2014

OBJECTIVE

Sarcopenic-obesity (SO) is characterized by the concomitant presence of low muscle mass and high adiposity. This study explores the association of body composition and SO phenotypes with cognitive function in older adults.

METHODS

Cross-sectional data in older adults (≥60 years) from NHANES 1999-2002 and 2011-2014 were used. In the 1999-2002 cohort, phenotypes were derived from body mass index (BMI) and dual-X-ray-absorptiometry, and cognition was assessed the by Digit-Symbol-Substitution-Test (DSST). In the 2011-2014 cohort, phenotypes were derived from BMI, waist-circumference (WC), and hand-grip-strength (HGS). Cognition was assessed using four tests: DSST, Animal Fluency, the Consortium-to-Establish-a-Registry-for-Alzheimer's-Disease-Delayed-Recall, and Word Learning. Mediation analysis was conducted to evaluate the contribution of inflammation (C-reactive-protein, CRP) and insulin resistance (Homeostatic-Model-Assessment-for-Insulin-Resistance, HOMA-IR) to the association between body composition and cognitive outcomes.

RESULTS

The SO phenotype had the lowest DSST mean scores (p < 0.05) and was associated with a significant risk of cognitive impairment [Odds Ratio (OR) = 1.9; 95%CI 1.0-3.7, p = 0.027] in the 1999-2002 cohort. A higher ratio of fat mass and fat free mass (FM/FFM) also showed a greater risk of cognitive impairment (OR = 2.0; 95%CI 1.3-3.1, p = 0.004). In the 2011-2014 cohort, the high WC-Low HGS group showed significantly lower scores on all four cognitive tests (p < 0.05) and a higher risk of cognitive impairment. CRP and HOMA-IR were significant partial mediators of the association between FM/FFM and DSST in the 1999-2002 cohort.

CONCLUSIONS

The SO phenotype was associated with a higher risk of cognitive impairment in older adults. Insulin resistance and inflammation may represent key mechanisms linking SO to the development of cognitive impairment.

Dynamic associations between glucose and ecological momentary cognition in Type 1 Diabetes

Type 1 diabetes (T1D) is a chronic condition characterized by glucose fluctuations. Laboratory studies suggest that cognition is reduced when glucose is very low (hypoglycemia) and very high (hyperglycemia). Until recently, technological limitations prevented researchers from understanding how naturally-occurring glucose fluctuations impact cognitive fluctuations. This study leveraged advances in continuous glucose monitoring (CGM) and cognitive ecological momentary assessment (EMA) to characterize dynamic, within-person associations between glucose and cognition in naturalistic environments. Using CGM and EMA, we obtained intensive longitudinal measurements of glucose and cognition (processing speed, sustained attention) in 200 adults with T1D. First, we used hierarchical Bayesian modeling to estimate dynamic, within-person associations between glucose and cognition. Consistent with laboratory studies, we hypothesized that cognitive performance would be reduced at low and high glucose, reflecting cognitive vulnerability to glucose fluctuations. Second, we used data-driven lasso regression to identify clinical characteristics that predicted individual differences in cognitive vulnerability to glucose fluctuations. Large glucose fluctuations were associated with slower and less accurate processing speed, although slight glucose elevations (relative to person-level means) were associated with faster processing speed. Glucose fluctuations were not related to sustained attention. Seven clinical characteristics predicted individual differences in cognitive vulnerability to glucose fluctuations: age, time in hypoglycemia, lifetime severe hypoglycemic events, microvascular complications, glucose variability, fatigue, and neck circumference. Results establish the impact of glucose on processing speed in naturalistic environments, suggest that minimizing glucose fluctuations is important for optimizing processing speed, and identify several clinical characteristics that may exacerbate cognitive vulnerability to glucose fluctuations.

Risk factors for cognitive impairment in middle-aged type 2 diabetic patients: a cross-sectional study

OBJECTIVE

The aim of this study was to investigate risk factors for cognitive impairment (CI) and explore the relationship between obesity and cognition in hospitalised middle-aged patients with type 2 diabetes (T2DM).

METHODS

Subjects were divided into normal cognitive function (NCF) (n=320) and CI (n=204) groups based on the results of the Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE). The risk factors for CI were determined by logistic regression analysis and generalised linear modelling. The associations between obesity parameters (body mass index (BMI) and waist circumference (WC)) and cognitive ability were studied with the use of linear regression analysis, piecewise regression modelling and interaction analysis. The receiver operating characteristic curve analysis was used to examine the diagnostic value of influencing factors for cc RESULTS: The prevalence of CI was 38.9% in hospitalised middle-aged T2DM patients (median age, 58 years). Age, WC, hypoglycaemic episode within past 3 months and cerebrovascular disease (CVD) were identified as independent risk factors for CI, while the independent protective factors were education, diabetic dietary pattern, overweight and obesity. BMI was a protective factor for the MoCA score within a certain range, whereas WC was a risk factor for the MMSE and MoCA scores. The area under the curve for the combination of BMI and WC was 0.754 (p<0.001).

CONCLUSION

Age, education, diabetic dietary pattern, WC, overweight, obesity, hypoglycaemic episode in 3 months and CVD may be potential influencing factors for the occurrence of CI in hospitalised middle-aged population with T2DM. The combination of BMI and WC may represent a good predictor for early screening of CI in this population. Nevertheless, more relevant prospective studies are still needed.

The association between regional adiposity, cognitive function, and dementia-related brain changes: a systematic review

Background

Adiposity has been previously associated with cognitive impairment and Alzheimer's disease and related disorders (ADRD). Body mass index (BMI) is the most common measure of global adiposity, but inconsistent results were found since it is a global measurement. BMI does not represent regional fat distribution which differs between sexes, race, and age. Regional fat distribution may contribute differently to cognitive decline and Alzheimer's disease (AD)-related brain changes. Fat-specific targeted therapies could lead to personalized improvement of cognition. The goal of this systematic review is to explore whether regional fat depots, rather than central obesity, should be used to understand the mechanism underlying the association between adiposity and brain.

Methods

This systematic review included 33 studies in the English language, conducted in humans aged 18 years and over with assessment of regional adiposity, cognitive function, dementia, and brain measures. We included only studies that have assessed regional adiposity using imaging technics and excluded studies that were review articles, abstract only or letters to editor. Studies on children and adolescents, animal studies, and studies of patients with gastrointestinal diseases were excluded. PubMed, PsychInfo and web of science were used as electronic databases for literature search until November 2022.

Results

Based on the currently available literature, the findings suggest that different regional fat depots are likely associated with increased risk of cognitive impairment, brain changes and dementia, especially AD. However, different regional fat depots can have different cognitive outcomes and affect the brain differently. Visceral adipose tissue (VAT) was the most studied regional fat, along with liver fat through non-alcoholic fatty liver disease (NAFLD). Pancreatic fat was the least studied regional fat.

Conclusion

Regional adiposity, which is modifiable, may explain discrepancies in associations of global adiposity, brain, and cognition. Specific regional fat depots lead to abnormal secretion of adipose factors which in turn may penetrate the blood brain barrier leading to brain damage and to cognitive decline.

The Association of Obesity and Overweight with Executive Functions in Community-Dwelling Older Women

Among the risk factors reported for cognitive decline, the literature highlights changes in body composition. Thus, the aim of the present study was to examine the relationship between obesity/overweight and executive functions in cognitively normal older adult women. This cross-sectional study included 224 individuals (60-80 years), stratified into normal weight (n = 45), overweight (n = 98), and obesity (n = 81). As outcomes, body mass index (BMI), waist circumference (WC), and Trail Making Test Parts A and B were assessed. We found positive correlations of BMI and WC with completion times of TMT-A and TMT-B, and a negative correlation of BMI and WC with education. ANCOVA showed an association between higher BMI and slower completion time of TMT-A, TMT-B, and ΔTMT (B-A). Impairment of executive functions of cognitively normal older women may be positively associated with obesity and negatively associated with years of education. The findings may contribute to designing strategies that make it possible to prevent cognitive decline in women during aging.

Consumption of Ultra-Processed Food and Cognitive Decline among Older Adults With Type-2 Diabetes

BACKGROUND

Ultra-processed food (UPF) consumption is related to increased morbidity and mortality. However, knowledge on its association with cognitive function is lacking. In this longitudinal study, we examined the associations between UPF intake and cognitive decline in older adults with type-2 diabetes (T2D).

METHODS

The sample included initially nondemented T2D older adults (≥65 years), from the Israel Diabetes and Cognitive Decline study, who had complete information on nutrition at baseline and at least 3 cognitive assessments (mean follow-up 5.3 ± 1.5 years). Nutritional intake was evaluated by a validated Food-Frequency Questionnaire, and foods were categorized as UPF based on NOVA classification. Percent of calories from UPF were calculated from total caloric consumption in total and specific food groups. Mixed effect models were used to examine the link between UPF intake (top vs bottom quartiles) and change in cognitive function overall and in specific domains, adjusting for potential confounders.

RESULTS

Of the total sample (N = 568; mean age 71.3 ± 4.5 years, 60% men), 141 consumed >31% kcal from UPF (top quartile). Greater intake of ultra-processed meat was associated with a faster decline in executive functions and global cognition (β = -0.041 ± 0.013; p = .002 and β = -0.026 ± 0.010; p = .011, respectively). Additionally, consumption of ultra-processed oils/spreads was associated with faster decline in executive functions and global cognition (β = -0.037 ± 0.014; p = .006 and β = -0.028 ± 0.010; p = .009, respectively). Total UPF consumption and UPF-derived from dairy products and bread/pastries/starch were not associated with cognitive change.

CONCLUSION

This study suggests that a high intake of ultra-processed meat and oils/spreads may be associated with accelerated cognitive decline in older individuals with T2D.

Recent Updates on Associations among Various Obesity Metrics and Cognitive Impairment: from Body Mass Index to Sarcopenic Obesity

Obesity and obesity-associated morbidity continues to be a major public health issue worldwide. Dementia is also a major health concern in aging societies and its prevalence has increased rapidly. Many epidemiologic studies have shown an association between obesity and cognitive impairment, but this relationship is not as well established as other comorbidities. Conflicting results related to the age and sex of participants, and the methodology used to define obesity and dementia may account for the uncertainty in whether obesity is a modifiable risk factor for dementia. More recently, sarcopenia and sarcopenic obesity have been reported to be associated with cognitive impairment. In addition, new mediators such as the muscle-myokine-brain axis and gut-microbiota-brain axis have been suggested and are attracting interest. In this review, we summarize recent evidence on the link between obesity and cognitive impairment, especially dementia. In particular, we focus on various metrics of obesity, from body mass index to sarcopenia and sarcopenic obesity.

Stability in BMI over time is associated with a better cognitive trajectory in older adults

OBJECTIVE

Evidence on simultaneous changes in body mass index (BMI) and cognitive decline, which better reflect the natural course of both health phenomena, is limited.

METHODS

We capitalized on longitudinal data from 15,977 initially non-demented elderly from the Alzheimer's Disease Centers followed for 5 years on average. Changes in BMI were defined as (1) last minus first BMI, (2) mean of all follow-up BMIs minus first BMI, and (3) standard deviation of BMI change from baseline and all follow-up visits (representing variability).

RESULTS

Participants with significant changes in BMI (increase or decrease of ≥5%), or who had greater variability in BMI, had faster cognitive decline. This pattern was consistent irrespective of normal (BMI < 25; N = 5747), overweight (25 ≤ BMI < 30; N = 6302), or obese (BMI ≥ 30; N = 3928) BMI at baseline.

CONCLUSIONS

Stability in BMI predicts better cognitive trajectories suggesting clinical value in tracking BMI change, which is simple to measure, and may point to individuals whose cognition is declining.

The Association Between Diet and Cardio-Metabolic Risk on Cognitive Performance: A Cross-Sectional Study of Middle-Aged Australian Adults

Adherence to different dietary patterns has been linked to the development of cognitive decline; yet little is known about whether this relationship is present in middle age. The current study aimed to explore the relationship between different dietary patterns, cognitive performance, and potential cardio-metabolic mechanisms for this relationship. Participants were recruited using a diet screening tool to ensure that the cohort had a range of diet quality ranging from relatively poor to relatively healthy. In a sample of 141 middle-aged adults (age: M = 52.84 years, SD = 6.87 years), multiple 24 h diet recalls were collected and used to score adherence to the Mediterranean diet, dietary approaches to stop hypertension (DASH) diet, and Mediterranean-DASH diet intervention for neurodegenerative delay (MIND) diet. Metabolic risk was assessed using the metabolic syndrome severity score (MetSSS) and arterial stiffness. Cognitive performance was assessed using the Swinburne University Computerized Cognitive Assessment Battery (SUCCAB). Adherence to the MIND diet was significantly related to Stroop Processing domain (β = 0.19, p = 0.035). None of the dietary patterns were significantly related to MetSSS or arterial stiffness. However, adherence to the DASH diet was significantly associated with two cardio-metabolic measures including lower augmentation index (β = -0.17, p = 0.032) and lowered cholesterol (β = -0.18, p = 0.041). Interestingly, two cardio-metabolic risk factors were also associated with better cognitive performance: MetSSS (β = 0.21, p = 0.010) and waist circumference (β = 0.22, p = 0.020). Together these findings suggest that diet in middle age may be important for cognitive functioning and cardio-metabolic risk. However, more research is needed in the form of randomized controlled trials to confirm the direction of these relationships.

Effect of Advanced Glycation End Products on Cognition in Older Adults with Type 2 Diabetes: Results from a Pilot Clinical Trial

BACKGROUND

Dietary advanced glycation end-products (AGEs) are linked to cognitive decline. However, clinical trials have not tested the effect of AGEs on cognition in older adults.

OBJECTIVE

The aim of the current pilot trial was to examine the feasibility of an intervention to reduce dietary AGEs on cognition and on cerebral blood flow (CBF).

METHODS

The design is a pilot randomized controlled trial of dietary AGEs reduction in older adults with type 2 diabetes. Seventy-five participants were randomized to two arms. The control arm received standard of care (SOC) guidelines for good glycemic control; the intervention arm, in addition to SOC guidelines, were instructed to reduce their dietary AGEs intake. Global cognition and CBF were assessed at baseline and after 6 months of intervention.

RESULTS

At baseline, we found a reverse association between AGEs and cognitive functioning, possibly reflecting the long-term toxicity of AGEs on the brain. There was a significant improvement in global cognition at 6 months in both the intervention and SOC groups which was more prominent in participants with mild cognitive impairment. We also found that at baseline, higher AGEs were associated with increased CBF in the left inferior parietal cortex; however, 6 months of the AGEs lowering intervention did not affect CBF levels, despite lowering AGEs exposure in blood.

CONCLUSION

The current pilot trial focused on the feasibility and methodology of intervening through diet to reduce AGEs in older adults with type 2 diabetes. Our results suggest that participants with mild cognitive impairment may benefit from an intensive dietary intervention.

Association of traditional and novel measures of central obesity with cognitive performance in older multi-ethnic Asians with type 2 diabetes

Literature evaluating the relationship between central obesity and cognitive deficits in type 2 diabetes (T2DM) remains scarce. This cross-sectional analysis explored the association of novel and traditional central obesity measures with cognitive performance in older (aged ≥60 years) non-demented multi-ethnic Asians with T2DM, including a stratified analysis by body mass index (BMI). Cognitive function was assessed using the Repeatable Battery for the Assessment of Neuropsychological Status. Central obesity measures including visceral fat area (VFA), waist circumference, waist:hip ratio, waist:height ratio, abdominal volume index, body roundness index and conicity index were measured and/or computed. In our cohort (N = 677; mean age = 67 ± 5 years, 51.7% men), VFA emerged as an associate of overall cognitive performance after covariate adjustment and Bonferroni correction (β = -.10, 95% CI = -0.18, -0.03), outperforming the other adiposity indices. Specifically, VFA was inversely associated with delayed memory and language scores. Additionally, compared with normal-weight individuals, excess visceral obesity (VFA ≥100 cm² ) was independently associated with lower cognitive scores to a greater extent in normal BMI (<23 kg/m² ) adults than in those with high BMI (≥23 kg/m² ). Assessment and management of visceral adiposity may help to prevent cognitive decline in older people with T2DM, and reduce the global burden of dementia in ageing populations.

Role of endothelium-independent vasodilation in the relationship between visceral adiposity and reduced cognitive performance in older adults with type 2 diabetes

OBJECTIVE

In this cross-sectional analysis, we sought to assess the relationship of adiposity and forearm microvascular reactivity with cognitive dysfunction among older Asians with type 2 diabetes (T2D).

METHODS

Subjects with T2D aged ≥ 55 years were analyzed (N = 907). Cognitive performance was assessed using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and Mini-Mental State Exam (MMSE). Visceral fat area (VFA) was estimated by tetrapolar multi-frequency bioimpedance. Forearm microvascular endothelium-dependent vasodilation (EDV) and endothelium-independent vasodilation (EIV) were assessed by laser Doppler imaging with iontophoresis.

RESULTS

RBANS total score was correlated with VFA, EDV, and EIV (all P < .05). However, VFA was correlated with EIV, but not with EDV. Multivariable linear regression showed significant association between VFA and RBANS total score (B = -0.02, 95% CI= -0.03 to -0.01) or memory (immediate and delayed) index scores. These associations were attenuated after adjustment for EIV. Mediation analysis showed that EIV partially mediated the relationship between visceral adiposity and RBANS scores (all Sobel tests P < .05). EIV also mediated the relationship between VFA and MMSE score.

CONCLUSIONS

Impaired endothelium-independent vascular smooth muscle reactivity may exert a mediatory effect on the association between increased visceral adiposity and decreased cognitive performance in older adults with T2D.

The factors contributing to cognitive dysfunction in type 2 diabetic patients

Backgrounds

The aim of the research was to investigate the factors contributing to cognitive dysfunction in type 2 diabetic patients, to distinguish the complex relationship between diabetic retinopathy (DR) and different cognitive status.

Methods

Two hundred and ninety-seven type 2 diabetes mellitus (T2DM) patients were enrolled in our study. We adopted the Clinical Dementia Rating (CDR), Mini-mental State Examination (MMSE) and Montreal Cognitive Assessment (MOCA) to evaluate the cognitive function. Firstly, cognition status was classified into dementia and non-dementia according to MMSE and CDR. Patients with non-dementia were further classified into mild cognitive impairment (MCI) and normal cognition status based on MOCA. The factors contributing to cognitive dysfunction were analyzed.

Results

Among the 297 T2DM subjects, 47 were enrolled in the dementia group and 174 in the MCI group according to a battery of cognitive function tests, presenting a prevalence of 15.8% and 58.6% respectively. After adjustment for age, sex, and education level, waist circumference and DR were risk factors for dementia (OR: 1.057, P=0.011; OR: 2.197, P=0.040). Low-density lipoprotein cholesterol (LDL-C) was a risk factor for MCI (OR: 1.635, P=0.047), while age at T2DM onset and moderate drinking were protective factors for MCI (OR: 0.936, P=0.044; OR: 0.289, P=0.004).

Conclusions

MCI is common in T2DM patients. Waist circumference and DR are risk factors of dementia, LDL-C is a risk factor for MCI, and moderate drinking and age at T2DM onset are protective factors for MCI. DR is unrelated to MCI in T2DM.

Association Between Waist Circumference and Dementia in Older Persons: A Nationwide Population-Based Study

OBJECTIVE

This study examined whether a positive association exists between waist circumference (WC) and dementia among older persons.

METHODS

The study population comprised 872,082 participants aged 65 years and older who participated in a Korean national health screening examination between January 1, 2009, and December 31, 2009. Adjusted hazard ratios and 95% CIs for dementia during follow-up from 2009 to 2015 were calculated according to baseline BMI and WC categories.

RESULTS

After a multivariate adjustment that included BMI, the hazard ratios for dementia showed a stepwise increase according to the increase in WC categories by 5 cm from 85 to 90 cm in men and from 80 to 85 cm in women until ≥ 110 cm (from 1.06 [95% CI: 1.03-1.09] to 1.64 [95% CI: 1.37-1.94] in men and from 1.04 [95% CI: 1.02-1.07] to 1.58 [95% CI: 1.36-1.84] in women). The influence of the current WC category for abdominal obesity on the risk of dementia was different according to BMI; especially, the normal weight men and women with abdominal obesity had a prominent increased risk of dementia compared with those without abdominal obesity.

CONCLUSIONS

Abdominal obesity, as measured by WC, was associated with significantly increased risk of dementia after adjustment for general obesity.

Olfactory Dysfunction Mediates Adiposity in Cognitive Impairment of Type 2 Diabetes: Insights From Clinical and Functional Neuroimaging Studies

OBJECTIVE

Large numbers of people with type 2 diabetes are obese. However, changes in cognition and related brain function in obese people with diabetes have not been characterized. Here, we investigated cognition, olfactory function, and odor-induced brain alterations in these patients and therapeutic effects of glucagon-like peptide 1 receptor agonists (GLP-1Ras) on their psychological behavior and olfactory networks.

RESEARCH DESIGN AND METHODS

Cognitive, olfactory, and odor-induced brain activation assessments were administered to 35 obese and 35 nonobese people with type 2 diabetes and 35 control subjects matched for age, sex, and education. Among them, 20 obese individuals with diabetes with inadequate glycemic control and metformin monotherapy received GLP-1Ra treatment for 3 months and were reassessed for metabolic, cognitive, olfactory, and neuroimaging changes.

RESULTS

Obese subjects with diabetes demonstrated lower general cognition and olfactory threshold scores, decreased left hippocampal activation, and disrupted seed-based functional connectivity with right insula compared with nonobese subjects with diabetes. Negative associations were found between adiposity and episodic memory and between fasting insulin and processing speed test time in diabetes. Mediation analyses showed that olfactory function and left hippocampus activation mediated these correlations. With 3-month GLP-1Ra treatment, obese subjects with diabetes exhibited improved Montreal Cognitive Assessment (MoCA) score, olfactory test total score, and enhanced odor-induced right parahippocampus activation.

CONCLUSIONS

Obese subjects with type 2 diabetes showed impaired cognition and dysfunctional olfaction and brain networks, the latter of which mediated adiposity in cognitive impairment of diabetes. GLP-1Ras ameliorated cognitive and olfactory abnormalities in obese subjects with diabetes, providing new perspectives for early diagnosis and therapeutic approaches for cognitive decrements in these patients.

Measures of general and abdominal obesity and disability severity in a large population of people with multiple sclerosis

Background:

Metabolic comorbidity is overrepresented in people with multiple sclerosis (MS) and is associated with adverse MS outcomes. Excess visceral adiposity, approximated using waist circumference (WC), is a risk factor for metabolic comorbidity and predicts poorer outcomes in other neurologic diseases.

Objective:

To evaluate the association between WC and clinical and disease characteristics in people with MS.

Methods:

North American Research Committee on MS (NARCOMS) registry participants reported height and weight (used to calculate body mass index (BMI)) and were mailed a tape measure with instructions to measure WC. We considered WC continuously and used cut-points derived from the abdominal obesity criteria for the metabolic syndrome (men: WC ⩾ 40 in; women: WC ⩾ 35 in). We assessed the association between WC and disability (Patient-Determined Disease Steps) and symptom severity (validated scales) using multivariable-adjusted multinomial models.

Results:

Of 6367 responders with MS, we included 5832 (92%). Of these, 3181 (55%) reported WC meeting criteria for the abdominal obesity component of metabolic syndrome. In multivariable models adjusting for overall obesity status, WC was associated with 47% increased odds of severe versus mild disability (odds ratio (OR): 1.47; 95% confidence interval (CI): 1.22–1.78).

Conclusions:

Increased WC is associated with more severe disability, even after adjusting for overall obesity in this large cross-sectional survey.

Exercise and the Aging Brain: Considerations for Sex Differences

Engaging in targeted exercise interventions is a promising, non-pharmacological strategy to mitigate the deleterious effects of aging and disease on brain health. However, despite its therapeutic potential, a large amount of variation exists in exercise efficacy in older adults aged 55 and older. In this review, we present the argument that biological sex may be an important moderator of the relationship between physical activity and cognition. Sex differences exist in dementia as well as in several associated risk factors, including genetics, cardiovascular factors, inflammation, hormones and social and psychological factors. Different exercise interventions, such as aerobic training and resistance training, influence cognition and brain health in older adults and these effects may be sex-dependent. The biological mechanisms underlying the beneficial effects of exercise on the brain may be different in males and females. Specifically, we examine sex differences in neuroplasticity, neurotrophic factors and physiological effects of exercise to highlight the possible mediators of sex differences in exercise efficacy on cognition. Future studies should address the potential sex difference in exercise efficacy if we are to develop effective, evidence-based exercise interventions to promote healthy brain aging for all individuals.

Subjective age and risk of incident dementia: Evidence from the National Health and Aging Trends survey

The present study examines the association between subjective age and risk of incident dementia in a large longitudinal sample of older adults. Participants were adults aged 65 years and older from the National Health and Aging Trends Study (NHATS). Subjective age, covariates, and cognitive status were assessed in 2011 and cognitive status was again assessed in 2012, 2013, 2014 and 2015. Incident dementia was determined based on answers from self and proxy respondents. The analyses included 4262 participants without dementia at baseline. Adjusting for demographic factors and baseline cognition, an older subjective age was related to higher likelihood of incident dementia. This association was partly accounted by depressive symptoms. Beyond the effect of chronological age, feeling older is associated with the risk of incident dementia.

Prediction of a new body shape index and body adiposity estimator for development of type 2 diabetes mellitus: The Rural Chinese Cohort Study

To compare the ability of a body shape index (ABSI) and body adiposity estimator (BAE) to BMI, waist circumference (WC) and waist:height ratio (WHtR) for predicting development of type 2 diabetes mellitus (T2DM) in rural adult Chinese. The prospective cohort study included 11 687 eligible participants who were free of T2DM at baseline. The risk of new-onset T2DM for ABSI, BAE, BMI, WC and WHtR quintiles was estimated by Cox proportional-hazards regression at follow-up. We also compared the power of ABSI and BAE to BMI, WC and WHtR for predicting the development of T2DM. With increasing ABSI, BAE, BMI, WC and WHtR, T2DM incidence was substantially increased (Ptrend<0·0001). After adjustment for multi-covariates, risk of T2DM was increased from the second to fifth quintile as compared with first quintile for ABSI (1·27; 95 % CI 0·95, 1·69; 1·35; 95 % CI 1·00, 1·82; 1·75; 95 % CI 1·33, 2·32 and 1·87; 95 % CI 1·40, 2·49; Ptrend<0·0001); BAE (1·82; 95 % CI 1·38, 2·41; 1·93; 95 % CI 1·38, 2·68; 2·73; 95 % CI 1·94, 3·84 and 4·18; 95 % CI 2·98, 5·87; Ptrend<0·0001); BMI (1·42; 95 % CI 1·03, 1·97; 1·62; 95 % CI 1·18, 2·23; 2·59; 95 % CI 1·92, 3·50 and 3·90; 95 % CI 2·90, 5·26; Ptrend<0·0001); WC (1·53; 95 % CI 1·08, 2·17; 1·66; 95 % CI 1·18, 2·33; 2·72; 1·97, 3·76 and 4·09; 95 % CI 2·97, 5·62; Ptrend<0·0001); and WHtR (1·40; 95 % CI 0·98, 1·99; 2·06; 95 % CI 1·47, 2·88; 2·90; 95 % CI 2·10, 4·01 and 4·22; 95 % CI 3·05, 5·85; Ptrend<0·0001). ABSI, BAE, BMI, WC and WHR were effective and comparable in discriminating cases from non-cases of T2DM. Risk of T2DM was increased with elevated ABSI and BAE, but the predictive ability for T2DM did not differ than that of BMI, WC and WHtR in a rural Chinese population.

Insulin signaling: An opportunistic target to minify the risk of Alzheimer's disease

Alzheimer's disease (AD) is progressive neurodegenerative disorder characterized by accumulation of senile plaques, neurofibrillary tangles (NFT) and neurodegeneration. The diabetes mellitus (DM) is one of the risk factors for AD pathogenesis by impairment in insulin signaling and glucose metabolism in central as well as peripheral system. Insulin resistance, impaired glucose and lipid metabolism are leading to the Aβ (Aβ) aggregation, Tau phosphorylation, mitochondrial dysfunction, oxidative stress, protein misfolding, memory impairment and also mark over Aβ transport through central to peripheral and vice versa. Several pathways, like enzymatic degradation of Aβ, forkhead box protein O1 (FOXO) signaling, insulin signaling shared common pathological mechanism for both AD and DM. Recent evidence showed that hyperinsulinemia and hyperglycemia affect the onset and progression of AD differently. Some researchers have suggested that hyperglycemia influences vascular tone, while hyperinsulinemia may underlie mitochondrial deficit. The objective of this review is to determine whether existing evidence supports the concept that impairment in insulin signaling and glucose metabolism play an important role in pathogenesis of AD. In the first part of this review, we tried to explain the interconnecting link between AD and DM, whereas the second part includes more information on insulin resistance and its involvement in AD pathogenesis. In the final part of this review, we have focused more toward the AD treatment by targeting insulin signaling like anti-diabetic, antioxidant, nutraceuticals and dietary supplements. To date, more researches should be done in this field in order to explore the pathways in insulin signaling, which might ameliorate the treatment options and reduce the risk of AD due to DM.