SciCombinator

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Journal: The journals of gerontology. Series A, Biological sciences and medical sciences

126

Obesity is a significant cause of functional limitations in older adults; yet, concerns that weight reduction could diminish muscle along with fat mass have impeded progress toward an intervention. Meal-based enhancement of protein intake could protect function and/or lean mass but has not been studied during geriatric obesity reduction.

Concepts: Metabolism, Nutrition, Glucose, Physical exercise, Mass, Adipose tissue, Kilogram, Weight

66

Current evidence that links “healthier” dietary patterns to better measured physical performance is mainly from older populations; little is known about the role of earlier diet. We examined adult diet quality in relation to physical performance at age 60-64 years.

Concepts: Cohort study, Human, Nutrition, Death, Biology, Test method, Diet, Diabetic diet

64

Several longitudinal studies found an inverse relationship between levels of physical activity and cognitive decline, dementia, and/or Alzheimer’s disease (AD), but results have been inconsistent. We followed an older, community-based cohort for over a decade to examine the association of physical activity with the risk of incident dementia and subclinical brain MRI markers of dementia.

Concepts: Alzheimer's disease, Cohort study, Longitudinal study, Epidemiology, Cognition, Neurology, Dementia, Framingham Heart Study

32

Nonhuman studies suggest a protective effect of caffeine on cognition. Although human literature remains less consistent, reviews suggest a possible favorable relationship between caffeine consumption and cognitive impairment or dementia. We investigated the relationship between caffeine intake and incidence of cognitive impairment or probable dementia in women aged 65 and older from the Women’s Health Initiative Memory Study.

Concepts: Psychology, Decision making, Cognitive psychology, Cognition, Memory, Thought, Cognitive neuroscience, Caffeine

28

The association between years of education and cognitive function in older adults has been studied extensively, but the role of quality of education is unknown. We examined indicators of childhood educational quality as predictors of cognitive performance and decline in later life.

Concepts: Psychology, Biology, Cognition, Cognitive science, Educational psychology, Social sciences, Association of Ideas, Coming of age

28

Gompertz-related distributions have dominated mortality studies for 187 years. However, nonrelated distributions also fit well to mortality data. These compete with the Gompertz and Gompertz-Makeham data when applied to data with varying extents of truncation, with no consensus as to preference. In contrast, Gaussian-related distributions are rarely applied, despite the fact that Lexis in 1879 suggested that the normal distribution itself fits well to the right of the mode. Study aims were therefore to compare skew-t fits to Human Mortality Database data, with Gompertz-nested distributions, by implementing maximum likelihood estimation functions (mle2, R package bbmle; coding given). Results showed skew-t fits obtained lower Bayesian information criterion values than Gompertz-nested distributions, applied to low-mortality country data, including 1711 and 1810 cohorts. As Gaussian-related distributions have now been found to have almost universal application to error theory, one conclusion could be that a Gaussian-related distribution might replace Gompertz-related distributions as the basis for mortality studies.

Concepts: Estimation theory, Maximum likelihood, Ronald Fisher, Normal distribution, Probability density function, Likelihood function, Uniform distribution

28

BACKGROUND: A reduction in maximal stroke volume (SV(max)) and total blood volume (TBV) has been hypothesized to contribute to the decline in maximal oxygen uptake (VO(2)max) with healthy aging. However, these variables have rarely been collected simultaneously in a board age range to support or refute this hypothesis. It is also unclear to what extent scaling size-related cardiovascular determinants of VO(2)max affects the interpretation of age-related differences. METHODS: A retrospective analysis of VO(2)max, maximal cardiac output (Q©max), TBV, and body composition including fat-free mass (FFM) in 95 (51% M) healthy adults ranging from 19-86 years. RESULTS: Absolute and indexed VO(2)max, Q©max, and maximal heart rate decreased in both sexes with age (p ≤ .031). SV(max) declined with age when scaled to total body mass or body surface area (p ≤ .047) but not when expressed in absolute levels (p = .120) or relative to FFM (p = .464). Absolute and indexed TBVs (mL/kg; mL/m(2)) were not significantly affected by age but increased with age in both sexes when scaled to FFM (p ≤ .013). A lower arteriovenous oxygen difference (a-vO(2)diff) contributed to the reduction in VO(2)max with age in treadmill exercisers (p = .004) but not in the entire cohort (p = .128). CONCLUSION: These results suggest (a) a reduction in absolute SV(max), and TBV do not contribute substantially to the age-related reduction in VO(2)max, which instead results from a smaller Q©max due to a lower maximal heart rate, and (b) body composition scaling methods should be used to accurately describe the effect of aging on physical function and cardiovascular variables.

Concepts: Blood, Cardiology, Heart, Affect, Heart rate, Exercise physiology, VO2 max, Blood volume

24

Aging frailty, characterized by decreased physical and immunological functioning, is associated with stem cell depletion. Human allogeneic mesenchymal stem cells (allo-hMSCs) exert immunomodulatory effects and promote tissue repair.

Concepts: Cell, Clinical trial, Cell division, Stem cell, Mesenchymal stem cell, Bone marrow, Stem cells, Immunology

23

The purpose of this study was to determine the joint associations of sedentary time and physical activity with mobility disability in older age.

Concepts: Death, Obesity, Overweight, Weight loss, Old age, Ageing

23

The small RhoGTPase Cdc42 is mechanistically linked to aging of multiple tissues and to rejuvenation of hematopoietic stem cells (HSCs) in mice. However, data validating Cdc42 activity and expression as biomarker for aging in humans are still missing. Here we hypothesized that Cdc42 might serve as a novel biomarker of aging in older adults and therefore we determined Cdc42 activity and expression levels in peripheral blood (PB) cells from a cohort of 196 donors. We investigated the association of these parameters with both chronological and biological aging. We also tested in this cohort of older adults a recently published algorithm determining chronological age based on DNA methylation profiles. A positive correlation with chronological age was found for both the level of Cdc42 mRNA and the level of active Cdc42 protein (the GTP bound form). Notably, the level of Cdc42 mRNA as well as total protein showed a specific strong association to cardiovascular disease (CVD) and Cdc42 mRNA levels also to a history of myocardial infarction (MI). In summary, these data validate Cdc42 as a blood biomarker of both chronological aging as well as aging-associated diseases like CVD and MI.

Concepts: DNA, Gene, Gene expression, Death, Senescence, Myocardial infarction, Gerontology, Ageing