The relationship between body mass index (BMI) (in midlife and late-life) and dementia was investigated in meta-analyses of 16 articles reporting on 15 prospective studies. Follow-ups ranged from 3.2 to 36.0 years. Meta-analyses were conducted on samples including 25 624 participants evaluated for Alzheimer's disease (AD), 15 435 participants evaluated for vascular dementia (VaD) and 30 470 followed for any type of dementia (Any Dementia). Low BMI in midlife was associated with 1.96 [95% confidence interval (CI): 1.32, 2.92] times the risk of developing AD. The pooled relative risks for AD, VaD and Any Dementia for overweight BMI in midlife compared with normal BMI were 1.35 (95% CI:1.19, 1.54), 1.33 (95% CI: 1.02, 1.75) and 1.26 (95% CI: 1.10, 1.44), respectively. The pooled relative risks of AD and Any Dementia for obese BMI in midlife compared to normal BMI were 2.04 (95% CI: 1.59, 2.62) and 1.64 (95% CI: 1.34, 2.00), respectively. Continuous BMI in late-life was not associated with dementia. Small numbers of studies included in pooled analyses reduce generalizability of findings, and emphasize the need for publication of additional findings. We conclude that underweight, overweight and obesity in midlife increase dementia risk. Further research evaluating late-life BMI and dementia is required.

https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1467-789X.2010.00825.x

Body mass index in midlife and late-life as a risk factor for dementia: a meta-analysis of prospective studies.

Obesity is a growing problem worldwide and is associated with a range of comorbidities, including cognitive dysfunction. In this review we will address the evidence that obesity and high fat feeding can lead to cognitive dysfunction. We will also examine the idea that obesity-associated systemic inflammation leads to inflammation within the brain, particularly the hypothalamus, and that this is partially responsible for these negative cognitive outcomes. Thus, obesity, and high fat feeding, lead to systemic inflammation and excess circulating free fatty acids. Circulating cytokines, free fatty acids and immune cells reach the brain at the level of the hypothalamus and initiate local inflammation, including microglial proliferation. This local inflammation likely causes synaptic remodeling and neurodegeneration within the hypothalamus, altering internal hypothalamic circuitry and hypothalamic outputs to other brain regions. The result is disruption to cognitive function mediated by regions such as hippocampus, amygdala, and reward-processing centers. Central inflammation is also likely to affect these regions directly. Thus, central inflammation in obesity leads not just to disruption of hypothalamic satiety signals and perpetuation of overeating, but also to negative outcomes on cognition.

Obesity and neuroinflammation: a pathway to cognitive impairment.

While dementia affects 6-10% of persons 65 years or older, industrialized countries have witnessed an alarming rise in obesity. However, obesity's influence on dementia remains poorly understood. The conducted a systematic review and meta-analysis. PUBMED search (1995-2007) resulted in 10 relevant prospective cohort studies of older adults (40-80 years at baseline) with end points being dementia and predictors including adiposity measures, such as body mass index (BMI) and waist circumference (WC). There was a significant U-shaped association between BMI and dementia (P= 0.034), with dementia risk increased for obesity and underweight. Pooled odds ratios (OR) and 95% confidence intervals (CI) for underweight, overweight and obesity compared with normal weight in relation to incident dementia were: 1.36 (1.07, 1.73), 0.88 (0.60, 1.27) and 1.42 (0.93, 2.18) respectively. Pooled ORs and 95% CI for obesity and incident Alzheimer's disease (AD) and vascular dementia were 1.80 (1.00, 3.29) vs. 1.73 (0.47, 6.31) and were stronger in studies with long follow-up (>10 years) and young baseline age (<60 years). Weight gain and high WC or skin-fold thickness increased risks of dementia in all included studies. The meta-analysis shows a moderate association between obesity and the risks for dementia and AD. Future studies are needed to understand optimal weight and biological mechanisms

/pdf/obesity-and-central-obesity-as-risk-factors-for-incident-1i4y5nvzew.pdf

Obesity and central obesity as risk factors for incident dementia and its subtypes: a systematic review and meta‐analysis

Obesity: overview of an epidemic.

Dementia is one of the most important neurological disorders in the elderly. Aging is associated with a large increase in the prevalence and incidence of degenerative (Alzheimer’s disease) and vascular dementia, leading to a devastating loss of autonomy. In view of the increasing longevity of populations worldwide, prevention of dementia has turned into a major public health challenge. In the past decade, several vascular risk factors have been found to be associated with vascular dementia but also Alzheimer’s disease. Some longitudinal studies, have found significant associations between hypertension, diabetus mellitus, and metabolic syndrome, assessed at middle age, and dementia. Studies assessing the link between hypercholesterolemia, atrial fibrillation, smoking, and dementia have given more conflicting results. Furthermore, some studies have highlighted the possible protective effect of antihypertensive therapy on cognition and some trials are evaluating the effects of statins and treatments for insulin resistance. Vascular risk factors and their treatments are a promising avenue of research for prevention of dementia, and further long-term, placebo-controlled, randomized studies, need to be performed.

/pdf/vascular-risk-factors-cognitve-decline-and-dementia-4fovu04595.pdf

Vascular risk factors, cognitve decline, and dementia

Background identification of modifiable risk factors is crucial in the prevention of dementia, given its limited treatment options. Studies on increased body mass index (BMI) as a risk factor for dementia show conflicting results. Methods we systematically retrieved and reviewed longitudinal population-based studies on increased BMI and dementia using a standard protocol. We searched Medline (1966-2006), Ageline (1978-2006), PsychInfo (1966-2006), CINAHL (1982-2006), and other relevant databases, including the reference lists of the eligible articles for review. Included studies were subjected to a quality assessment protocol. Results we identified eight studies that met our selection criteria. These studies covered 1,688 cases of dementia from 28,697 participants. After adjustment for age, smoking, comorbidities, and other confounders, four studies presented significantly increased risk of dementia with elevated BMI. Conclusion this systematic review supports the hypothesis that increased BMI is independently associated with increased risk of dementia. Long-term studies to examine the mechanisms underlying the relationship between obesity and dementia are needed.

The risk of dementia with increased body mass index

Cognitive impairment over the age of 85: Hospitalization and mortality

Macrovascular Complications of Diabetes in Older Adults

https://www.endo.theclinics.com/article/S0889-8529(06)00044-2/pdf

Ethnicity and diabetic heart disease.

Digital therapeutics (DTx) are a rapidly growing therapeutic category with more than 150 clinical trials evaluating US Food and Drug Administration-regulated DTx to develop additional evidence by the end of 2022. Investments in DTx development have doubled since 2019, reaching $14.7 billion in 2021. Prescription DTx are regulated by the US Food and Drug Administration and require demonstration of efficacy and safety prior to commercialization and reimbursement by payers. Drawing insights from the Massachusetts Medicaid program's early experience with prescription DTx, we provide an overview of this new category of therapeutics and suggest a roadmap for payers and policymakers to evaluate the value of prescription DTx for their member population. Finally, we propose solutions to potential challenges that may be encountered in the DTx coverage and reimbursement management.

Jatin K. Dave

Papers

The risk of dementia with increased body mass index

Cognitive impairment over the age of 85: Hospitalization and mortality

Macrovascular Complications of Diabetes in Older Adults

Ethnicity and diabetic heart disease.

Prescription digital therapeutics: Applying Medicaid experience to value assessment and formulary management.