The Relationship between Obesity and the High Probability of Dementia Based on the Body Mass Index and Waist Circumference

Mechanisms Underlying Obesity-induced Aβ Accumulation in Alzheimer's Disease: A Qualitative Review

Epidemiological studies show that individuals with obesity are more likely to develop Alzheimer's disease (AD) than those who do not have obesity. However, the mechanisms underlying the relationship between obesity and AD are not entirely unclear. Here, we have reviewed and analyzed relevant articles published in the literature and found that obesity has correlation or potential increase in the levels of β-amyloid (Aβ) protein, which may explain why people with obesity are more likely to suffer from AD. Additionally, the published findings point to the roles of obesity-related metabolic disorders, such as diabetes, inflammation, oxidative stress, and imbalance in gut microbiota in Aβ accumulation caused by obesity. Therefore, in-depth experimental and clinical studies on these mechanisms in the future may help shed light on appropriate prevention and treatment strategies for AD, such as dietary changes and regular exercise to reverse or prevent obesity and related metabolic disorders.

Higher visceral adipose tissue is associated with decreased memory suppression ability on food-related thoughts: A 1-year prospective ERP study

Memory about food and eating is crucial in regulating appetite and eating behaviors. Successfully stopping vivid imagination of delicious food could help reduce food craving and thus reduce the possibility of further intake. Memory inhibition is a cognitive process that involves intentional suppression of certain memories coming to consciousness. Successful memory suppression derives from inhibitory control. Although considerable work has consistently observed the impairment in motor or response inhibitory control among individuals with obesity, there has been a lack of investigation into the influence of bodyweight status on memory inhibitory control. To fill this gap, current study investigated behavioral and neurophysiological correlates of memory suppression in young women. Using Think/No-Think task and event-related potentials among 47 females, we found that participants with higher visceral adipose tissue (VAT) showed a tendency towards decreased suppression ability for memories related to food but not memories related to nonfood items. In depth analysis showed that decrease in the differences in P2 amplitudes between suppression vs. retrieval of food-related memories mediated the impairment of suppression ability by high VAT. We then tested whether individual differences in memory suppression ability as well as ERP correlates predicted future BMI or VAT change over 1-year follow-up. Results showed that P2 amplitudes when retrieving food-related memory could predict VAT change at 1-year follow-up among participants with healthy BMI. These observations suggest a hypersensitivity inference hypothesis underlying memory control impairments. To be specific, deficits in memory suppression may be in part resulted from elevated sensitivity to the cues coupling with food-related memory. It extends previous studies of memory suppression with food rewards and provides the first evidence to help understand the relationship between inhibitory control on food-related memory and obesity.

Association among cognitive function, physical fitness, and health status in older women

This study examined the association among cognitive function, physical fitness, and health status in healthy older women. Ninety-four females aged from 62 to 86 years (72.66±5.38 years) from community healthcare centers and an exercise club in Seoul, South Korea. Cognitive function was assessed using the Seoul Neuropsychological Screening Battery. Physical performance comprised cardiorespiratory endurance, lower extremity strength, active balance ability, and walking speed. Health status included blood pressure and waist circumference. Multiple linear regression analyses were performed to determine the relationship among cognitive function, fitness components, and health status, with age and educational attainment as covariates. In the unadjusted model, attention was significantly associated with cardiovascular endurance (B=0.19, P<0.05). Memory was significantly associated with lower limb strength (B=0.77, P<0.05) and active balance ability (B=2.35, P<0.05). In the adjusted model, attention was significantly associated with cardiovascular endurance (B=0.15, P<0.05). Memory was significantly associated with lower limb strength (B=0.87, P<0.05). In both models, cognitive function was not significantly associated with any health status variable. Though limited by a relatively small sample of female participants, who were healthy registrants of a community exercise program with normal cognitive function, the current study demonstrates that cognitive function is significantly associated with physical fitness, but not with health status, in healthy older women.

Systemic inflammation mediates the negative relationship between visceral adiposity and cognitive control

Elevated visceral adipose tissue (VAT) has been associated with cardiometabolic risk factors including chronic systemic low-grade inflammation. Whereas the cognitive implications of inflammation have been extensively studied in preclinical models, the influence of inflammatory cytokines on cognitive function in humans is unclear. This study aimed to investigate the relations among VAT, inflammatory cytokines, and cognitive control. We hypothesized that inflammatory markers would mediate the negative influence of VAT on selective attention. Participants between 25 and 46 years (N = 115, 43 females) underwent a DXA scan to estimate VAT. A modified Eriksen Flanker task was used to assess attentional inhibitory control while event-related potentials were recorded. ELISA was used to quantify plasma C-reactive protein (CRP) and Interleukin-6 (IL-6) concentrations. Mediation modeling while controlling for diet quality and education level revealed that CRP concentrations significantly mediated the relationship between VAT and incongruent trial accuracy (indirect effect 95% CI {-0.24, -0.01}). Further, IL-6 concentrations had a significant mediation effect on the relationship between VAT and incongruent P3 peak latency (indirect effect 95% CI {0.05, 1.39}). These results suggest that mechanisms by which visceral adiposity exerts a negative influence on cognitive function includes systemic inflammation.

Gender differences in the relationship between dietary energy and macronutrients intake and body weight outcomes in Chinese adults

BACKGROUND

To explore the gender differences in the relationship between dietary energy and macronutrients intake and body weight outcomes in Chinese adults.

METHODS

Data from the China Health and Nutrition Survey (CHNS, 2015) for10,898 participants aged 18-64 years. Three consecutive 24-h dietary recalls was used to assess the dietary intake. Quantile regression models for body mass index (BMI) and waist circumference (WC) were performed separately for each sex.

RESULTS

Adult males showed greater absolute intakes of energy and macronutrients as compared to females as per the body weight outcomes. A 10% increase in BMI resulted in an additional intake of 0.002-0.004 kcal/d of dietary energy, 0.032-0.057 g/d of fats, 0.039-0.084 g/d of proteins, and 0.018-0.028 g/d of carbohydrates across all quantiles in males (p <  0.05). A 10% increase in WC lead to an additional intake of 0.004-0.008 kcal/d of dietary energy, 0.051-0.052 g/d of carbohydrates across the entire quantile in males (p <  0.05), and an increased intake of 0.060-0.150 kcal/d of fat in females (p <  0.05).

CONCLUSIONS

Dietary fat intake could be the risk factor of abdominal obesity in women. The importance of gender-specific evidence should be considered before promoting macronutrient allocation for the prevention and treatment of obesity.

Associations Among Health Insurance Type, Cardiovascular Risk Factors, and the Risk of Dementia: A Prospective Cohort Study in Korea

Due to an aging population, dementia incidence has rapidly increased in South Korea, heaping psychological and economic burdens upon families and the society. This study was aimed at investigating the associations of health insurance type and cardiovascular risk factors with the risk of dementia. The study was performed using data from 15,043 participants aged 60 years and above, enrolled in the Seoul Dementia Management Project in 2008 and followed up until 2012. Factors such as demographic data, health insurance type, lifestyle factors, and cardiovascular risk factors were subjected to Cox proportional hazard regression analysis to identify their associations with dementia incidence. During the follow-up, 495 participants (3.3%) developed dementia. Medical Aid beneficiaries were associated with an increase in the risk of dementia (hazard ratio [HR] 1.77, 95% confidence interval [CI] 1.421–2.215). Upon analyzing a composite cardiovascular risk score derived from all five cardiovascular risk factors, the risk for dementia incidence in participants increased from 1.56 for the presence of three risk factors to 2.55 for that of four risk factors (HR 2.55, 95% CI 1.174–5.546), compared with those who had no risk factors. The Medical Aid beneficiaries of health insurance type and the presence of multiple cardiovascular risk factors were found to be associated with a higher risk of dementia incidence.

[Factors affecting dementia prevalence in people aged 60 or over: a community based cross-sectional study]

PURPOSE

This study was done to examine the association between body mass index (BMI) and any type of clinical dementia.

METHODS

Participants were 60,321 people over 60 years of age enrolled in the Seoul Dementia Management Project in 2011. K-MMSE was used to classify participants as having a cognitive impairment and the Clinical Dementia Rating or DSM-IV by psychiatrists or neurologists to determine whether participants were in the dementia group or the non-dementia group. Descriptive statistics, chi-square test, and binary logistic regression analysis were performed.

RESULTS

In the univariate analysis, age, education level, living with spouse, BMI, alcohol consumption, and exercise were significantly associated with dementia. In multivariable analysis, increasing age was positively associated with dementia, and educational level was negatively associated with dementia. The exercise group had a lower prevalence of dementia than the non-exercise group. The odds ratio of dementia in the over-weight and obese groups compared to the normal group was 0.85 (95% CI 0.60, 0.98) and 0.64 (95%CI 0.46, 0.75), respectively.

CONCLUSION

Results indicate that dementia is negatively associated with increasing BMI in people aged 60 years or older, but a prospective cohort study is needed to elucidate the causal effect relationship between BMI and dementia.