Pathophysiological Links Between Obesity and Dementia

Body roundness index and cognitive function in older adults: a nationwide perspective

Background

Obesity negatively impacts cognitive function. However, the correlation between the body roundness index (BRI) and cognitive performance remains inadequately explored.

Methods

This study used data from the National Health and Nutrition Examination Survey (NHANES) collected from 2011 to 2014 to examine the correlation between BRI and cognitive function in individuals aged 65 and older. Models of multiple linear regression were used to investigate the relationship between BRI and cognitive performance. Additionally, smoothed curve fittings explored potential non-linear associations. Interaction tests and subgroup analyses were also performed.

Results

One thousand eight hundred seventy participants were taken into account, revealing an important negative relationship between BRI levels and cognitive performance. In the fully adjusted model, elevated BRI was substantially correlated with lower Digit Symbol Substitution Test (DSST) scores (β = -0.34, 95% CI = -0.64 to -0.05, p = 0.023), indicating that the higher BRI values are linked to worse cognitive performance. Sex differences were observed, with males showing a stronger negative association (p for interaction = 0.040).

Conclusion

Elevated BRI is related to worse cognitive function in the elderly population.

Population attributable fractions for risk factors for dementia in seven Latin American countries: an analysis using cross-sectional survey data

BACKGROUND

Approximately 40% of dementia cases worldwide are attributable to 12 potentially modifiable risk factors. However, the proportion attributable to these risks in Latin America remains unknown. We aimed to determine the population attributable fraction (PAF) of 12 modifiable risk factors for dementia in seven countries in Latin America.

METHODS

We used data from seven cross-sectional, nationally representative surveys with measurements of 12 modifiable risk factors for dementia (less education, hearing loss, hypertension, obesity, smoking, depression, social isolation, physical inactivity, diabetes, excessive alcohol intake, air pollution, and traumatic brain injury) done in Argentina, Brazil, Bolivia, Chile, Honduras, Mexico, and Peru. Data were collected between 2015 and 2021. Sample sizes ranged from 5995 to 107 907 participants (aged ≥18 years). We calculated risk factor prevalence and communalities in each country and used relative risks from previous meta-analyses to derive weighted PAFs. Pooled PAFs for Latin America were obtained using random effect meta-analyses.

FINDINGS

The overall proportion of dementia cases attributed to 12 modifiable risk factors varied across Latin American countries: weighted PAF 61·8% (95% CI 37·9-79·5) in Chile, 59·6% (35·8-77·3) in Argentina, 55·8% (35·7-71·5) in Mexico, 55·5% (35·9-70·4) in Bolivia, 53·6% (33·0-69·3) in Honduras, 48·2% (28·1-63·9) in Brazil, and 44·9% (25·8-61·2) in Peru. The overall PAF for dementia was 54·0% (48·8-59·6) for Latin America. The highest weighted PAFs in Latin American countries overall were for obesity (7%), physical inactivity (6%), and depression (5%).

INTERPRETATION

The estimated PAFs for Latin American countries were higher than previous global estimates. Obesity, physical inactivity, and depression were the main risk factors for dementia across seven Latin American countries. These findings have implications for public health and individually targeted dementia prevention strategies in Latin America. Although these results provide new information about Latin American countries, demographics and representativeness variations across surveys should be considered when interpreting these findings.

FUNDING

None.

Could the Early Detection of Atrial Fibrillation Reduce the Risk of Developing Dementia?

Atrial fibrillation (AF) and dementia are major global public health issues and share common risk factors, especially after the age of 65 and regardless of the presence of stroke. Despite accounting for potential confounders, AF appears to be an independent risk factor for cognitive decline and dementia. The mechanisms are likely to be multifactorial and may include AF-related ischemic stroke, cerebral hypoperfusion, microbleeds, systemic inflammation, genetic factors, and small vessel disease, leading to brain atrophy and white matter damage. The early aggressive management of AF and comorbidities may reduce the risk of dementia. Indeed, the early detection of AF-related cognitive impairment should allow for the early implementation of measures to prevent the development of dementia, mainly through integrative approaches involving the correction of risk factors and maintenance of rhythm control. Well-designed prospective studies are needed to determine whether early detection and AF treatment can prevent dementia and identify whether optimal integrative measures are effective in preventing cognitive impairment and dementia.

Vascular dementia: From pathobiology to emerging perspectives

Vascular dementia (VaD) is the second most common type of dementia. VaD is synonymous with ageing, and its symptoms place a significant burden on the health and wellbeing of older people. Despite the identification of a substantial number of risk factors for VaD, the pathological mechanisms underpinning this disease remain to be fully elucidated. Consequently, a biogerontological imperative exists to highlight the modifiable lifestyle factors which can mitigate against the risk of developing VaD. This review will critically examine some of the factors which have been revealed to modulate VaD risk. The survey commences by providing an overview of the putative mechanisms which are associated with the pathobiology of VaD. Next, the factors which influence the risk of developing VaD are examined. Finally, emerging treatment avenues including epigenetics, the gut microbiome, and pro-longevity pharmaceuticals are discussed. By drawing this key evidence together, it is our hope that it can be used to inform future experimental investigations in this field.