A Proposal for Finite But Unbounded Human Lifetimes

Close analysis of an extensive data set combined with independent evidence prompts our proposal to view human lifetimes as individually finite but collectively unbounded. We formulate a model incorporating this idea whose predictions agree very well with the observed data. In the model, human lifetimes are theoretically unbounded, but the probability of an individual living to an extreme age is negligible, so lifetimes are effectively limited. Our model incorporates a mortality hazard rate plateau and a late-life mortality deceleration effect in conjunction with a newly observed advanced age mortality acceleration. This reconciles many previously observed effects. The model is temporally stable: consistent with observation, parameters do not change over time. As an application, assuming no major medical advances, we predict the emergence of many individuals living past 120, but due to accelerating mortality find it unlikely that any will subsequently survive to an age of 125.

An examination of the quality of late-life depression websites on the Internet (Preprint)

BACKGROUND The Internet can increase the accessibility of mental health information and improve the mental health literacy of older adults. The quality of mental health information on the Internet can be inaccurate or biased, leading to misinformation OBJECTIVE This study’s objectives were to evaluate the quality, usability, and readability of websites providing information concerning depression in later life. METHODS Websites were identified through a Google search, and evaluated by assessing quality (DISCERN), usability (Patient Education Materials Assessment Tool; PEMAT) and readability (Simple Measure of Gobbledygook; SMOG). RESULTS The overall quality of late-life depression websites (N = 19) was moderate, usability was low, and readability was poor. No significant relationship was found between quality and readability of websites. CONCLUSIONS Websites can be improved by enhancing information quality, usability, and readability related to late-life depression. The use of high-quality websites may improve mental health literacy and shared treatment decision-making for older adults.

Characteristics of Dysregulated Proinflammatory Cytokines and Cognitive Dysfunction in Late-Life Depression and Amnestic Mild Cognitive Impairment

BackgroundLate-life depression (LLD) and amnestic mild cognitive impairment (aMCI) are two different diseases associated with a high risk of developing Alzheimer’s disease (AD). Both diseases are accompanied by dysregulation of inflammation. However, the differences and similarities of peripheral inflammatory parameters in these two diseases are not well understood.MethodsWe used Luminex assays to measure 29 cytokines simultaneously in the plasma of two large cohorts of subjects at high risk for AD (23 LLD and 23 aMCI) and 23 normal controls (NCs) in the community. Demographics and lifestyle factors were also collected. Cognitive function was evaluated with the Chinese versions of the Montreal Cognitive Assessment (C-MoCA) and neuropsychological test battery (NTB).ResultsWe observed a remarkably increased level of IL-6 in the plasma and reduced levels of chemokines (CXCL11 and CCL13) in the LLD group compared with the aMCI group. The LLD group also showed lower levels of CXCL16 than the NC group. Furthermore, altered cytokine levels were associated with abnormal results in neuropsychological testing and Geriatric Depression Scale scores in both the LLD and aMCI groups. Notably, combinations of cytokines (IL-6 and CCL13) and two subitems of C-MoCA (orientation and short-term memory) generated the best area under the receiver operating characteristic curve (AUROC = 0.974).ConclusionA novel model based on proinflammatory cytokines and brief screening tests performs with fair accuracy in the discrimination between LLD and aMCI. These findings will give clues to provide new therapeutic targets for interventions or markers for two diseases with similar predementia syndromes.

Association of improved air quality with lower dementia risk in older women

Late-life ambient air pollution is a risk factor for brain aging, but it remains unknown if improved air quality (AQ) lowers dementia risk. We studied a geographically diverse cohort of older women dementia free at baseline in 2008 to 2012 (n = 2,239, aged 74 to 92). Incident dementia was centrally adjudicated annually. Yearly mean concentrations of fine particulate matter (PM2.5) and nitrogen dioxide (NO2) were estimated using regionalized national universal kriging models and averaged over the 3-y period before baseline (recent exposure) and 10 y earlier (remote exposure). Reduction from remote to recent exposures was used as the indicator of improved AQ. Cox proportional hazard ratios (HRs) for dementia risk associated with AQ measures were estimated, adjusting for sociodemographic, lifestyle, and clinical characteristics. We identified 398 dementia cases during follow up (median = 6.1 y). PM2.5 and NO2 reduced significantly over the 10 y before baseline. Larger AQ improvement was associated with reduced dementia risks (HRPM2.5 0.80 per 1.78 μg/m3, 95% CI 0.71–0.91; HRNO2 0.80 per 3.91 parts per billion, 95% CI 0.71–0.90), equivalent to the lower risk observed in women 2.4 y younger at baseline. Higher PM2.5 at baseline was associated with higher dementia risk (HRPM2.5 1.16 per 2.90 μg/m3, 95% CI 0.98–1.38), but the lower dementia risk associated with improved AQ remained after further adjusting for recent exposure. The observed associations did not substantially differ by age, education, geographic region, Apolipoprotein E e4 genotypes, or cardiovascular risk factors. Long-term AQ improvement in late life was associated with lower dementia risk in older women.