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Uncertainty exists regarding the relation of body size and weight change with dementia risk. As populations continue to age and the global obesity epidemic shows no sign of waning, reliable quantification of such associations is important. We examined the relationship of body mass index, waist circumference, and annual percent weight change with risk of dementia and its subtypes by pooling data from 19 prospective cohort studies and four clinical trials using meta-analysis. Compared with body mass index-defined lower-normal weight (18.5-22.4 kg/m 2 ), the risk of all-cause dementia was higher among underweight individuals but lower among those with upper-normal (22.5-24.9 kg/m 2 ) levels. Obesity was associated with higher risk in vascular dementia. Similarly, relative to the lowest fifth of waist circumference, those in the highest fifth had nonsignificant higher vascular dementia risk. Weight loss was associated with higher all-cause dementia risk relative to weight maintenance. Weight gain was weakly associated with higher vascular dementia risk. The relationship between body size, weight change, and dementia is complex and exhibits non-linear associations depending on dementia subtype under scrutiny. Weight loss was associated with an elevated risk most likely due to reverse causality and/or pathophysiological changes in the brain, although the latter remains speculative., (© 2020 The Authors. Obesity Reviews published by John Wiley & Sons Ltd on behalf of World Obesity Federation.)

Background: Recently, the LIfestyle for BRAin health (LIBRA) index was developed to assess an individual's prevention potential for dementia., Objective: We investigated the predictive validity of the LIBRA index for incident dementia in midlife, late life, and the oldest-old., Methods: 9,387 non-demented individuals were recruited from the European population-based DESCRIPA study. An individual's LIBRA index was calculated solely based on modifiable risk factors: depression, diabetes, physical activity, hypertension, obesity, smoking, hypercholesterolemia, coronary heart disease, and mild/moderate alcohol use. Cox regression was used to test the predictive validity of LIBRA for dementia at follow-up (mean 7.2 y, range 1-16)., Results: In midlife (55-69 y, n = 3,256) and late life (70-79 y, n = 4,320), the risk for dementia increased with higher LIBRA scores. Individuals in the intermediate- and high-risk groups had a higher risk of dementia than those in the low-risk group. In the oldest-old (80-97 y, n = 1,811), higher LIBRA scores did not increase the risk for dementia., Conclusion: LIBRA might be a useful tool to identify individuals for primary prevention interventions of dementia in midlife, and maybe in late life, but not in the oldest-old.

Introduction: Few recent studies have suggested declining trends in dementia frequency. French cohorts with long follow-up allowed us to explore incidence evolution trends., Methods: Two different populations of subjects aged ≥65 years included in 1988-1989 (n = 1469) and 1999-2000 (n = 2104) were followed up over 10 years, with systematic assessment for cognition and dementia. Multistates illness-death models were used to compare dementia incidence using both clinical and algorithmic diagnoses., Results: Using the algorithmic diagnosis, incidence declined significantly overall and for women (age-adjusted hazard ratio [HR] = 0.62; confidence interval (CI) = 0.48-0.80 for women between the two populations). Differences in education, vascular factors, and depression accounted only to some extent for this reduction (women full-adjusted HR = 0.73; CI = 0.57-0.95). No significant decreasing trends were found for men or when using the clinical diagnosis for either sex., Discussion: Our study provides further support for a decrease in dementia incidence in women using algorithmic diagnosis. Changes in diagnostic boundaries mask this reduction., (Copyright © 2016 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved.)