Alzheimer's disease (AD) and Parkinson's disease (PD) are devastating, frequent, and still incurable neurodegenerative diseases that manifest as cognitive and motor disorders. Epidemiological data support an inverse relationship between the amount of physical activity (PA) undertaken and the risk of developing these two diseases. Beyond this preventive role, exercise may also slow down their progression. Several mechanisms have been suggested for explaining the benefits of PA in the prevention of AD. Aerobic physical exercise (PE) activates the release of neurotrophic factors and promotes angiogenesis, thereby facilitating neurogenesis and synaptogenesis, which in turn improve memory and cognitive functions. Research has shown that the neuroprotective mechanisms induced by PE are linked to an increased production of superoxide dismutase, endothelial nitric oxide synthase, brain-derived neurotrophic factor, nerve growth factor, insulin-like growth factor, and vascular endothelial growth factor, and a reduction in the production of free radicals in brain areas such as the hippocampus, which is particularly involved in memory. Other mechanisms have also been reported in the prevention of PD. Exercise limits the alteration in dopaminergic neurons in the substantia nigra and contributes to optimal functioning of the basal ganglia involved in motor commands and control by adaptive mechanisms involving dopamine and glutamate neurotransmission. AD and PD are expansive throughout our ageing society, and so even a small impact of nonpharmacological interventions, such as PA and exercise, may have a major impact on public health.

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A larger, longer trial is required to determine whether exercise has greater health benefits than nonphysical interventions for institutionalized PWDs.

IMPORTANCE Long-term exercise benefits on prevalent adverse events in older populations, such as falls, fractures, or hospitalizations, are not yet established or known. OBJECTIVE To systematically review and investigate the association of long-term exercise interventions (Ն1 year) with the risk of falls, injurious falls, multiple falls, fractures, hospitalization, and mortality in older adults. DATA SOURCES PubMed, Cochrane Central Register of Controlled Trials, SportDiscus, PsychInfo, and Ageline were searched through March 2018. STUDY SELECTION Exercise randomized clinical trials (RCTs) with intervention length of 1 year or longer, performed among participants 60 years or older. DATA EXTRACTION AND SYNTHESIS Two raters independently screened articles, abstracted the data, and assessed the risk of bias. Data were combined with risk ratios (RRs) using DerSimonian and Laird's random-effects model (Mantel-Haenszel method). MAIN OUTCOMES AND MEASURES Six binary outcomes for the risk of falls, injurious falls, multiple falls (Ն2 falls), fractures, hospitalization, and mortality. RESULTS Forty-six studies (22 709 participants) were included in the review and 40 (21 868 participants) in the meta-analyses (mean [SD] age, 73.1 [7.1] years; 15 054 [66.3%] of participants were women). The most used exercise was a multicomponent training (eg, aerobic plus strength plus balance); mean frequency was 3 times per week, about 50 minutes per session, at a moderate intensity. Comparator groups were often active controls. Exercise significantly decreased the risk of falls (n = 20 RCTs; 4420 participants; RR, 0.88; 95% CI, 0.79-0.98) and injurious falls (9 RTCs; 4481 participants; RR, 0.74; 95% CI, 0.62-0.88), and tended to reduce the risk of fractures (19 RTCs; 8410 participants; RR, 0.84; 95% CI, 0.71-1.00; P = .05). Exercise did not significantly diminish the risk of multiple falls (13 RTCs; 3060 participants), hospitalization (12 RTCs; 5639 participants), and mortality (29 RTCs; 11 441 participants). Sensitivity analyses provided similar findings, except the fixed-effect meta-analysis for the risk of fracture, which showed a significant effect favoring exercisers (RR, 0.84; 95% CI, 0.70-1.00; P = .047). Meta-regressions on mortality and falls suggest that 2 to 3 times per week would be the optimal exercise frequency. CONCLUSIONS AND RELEVANCE Long-term exercise is associated with a reduction in falls, injurious falls, and probably fractures in older adults, including people with cardiometabolic and neurological diseases.

Until 2002, coronaviruses (HCoV-NL63, HCoV-229E, HCoV-OC43 and HKU) were first known to cause common cold in humans. However, in 2002 the SARS-CoV emerged, and then in 2013 the MERS-CoV. The SARS-CoV and MERS-CoV caused severe respiratory syndrome and were highly pathogenic for humans, because of their ability to adapt to their host, notably to increase affinity for their receptor, leading to high infectivity in humans (1, 2). In December 2019, a new coronavirus, first called 2019-nCov and then SARS-CoV-2 for severe acute respiratory syndrome coronavirus 2, was identified in Wuhan, China (3). SARS-CoV-2 spreads very efficiently, causing the current COVID-19 (Coronavirus Disease 2019) pandemic, that by mid-May 2020 has already killed more than 300,000 people all over the world. The highest morbi-mortality of COVID-19 is observed among older patients (4). Patients in intensive care unit (ICU) are older than patients not requiring ICU (5). In a study using an observational database from 169 hospitals in Asia, Europe, and North America, an age of more than 65 years-old was associated with a higher risk of in-hospital death: 10.0% mortality rates for people ≥ 65 years-old vs. 4.9% for those < 65 years-old (6). In France, 3.6% of infected individuals needed to be hospitalized, with an average death rate of 0.7% ranging from 0.001% in individuals < 20 years-old, to 10.1% in those > 80 years-old (7). Not all older adults appear to be equally vulnerable to SARS-CoV-2 infection (8). Frailty is a clinical syndrome in older adults characterized by an increased vulnerability for adverse health outcomes and aging-associated functional declines (9). Frail older adults, especially those with comorbidities (eg, hypertension, obesity, diabetes) are at higher risk of death if they get infected than younger adults (10). Prevention interventions need to be developed to reduce the impact of COVID-19 in older people. Geroscience is an interdisciplinary field that seeks to understand the links of biological mechanisms of aging with biological mechanisms of disease and body functions (eg, mobility, cognition) to ultimately find potential interventions and promote health in older adults (11). In this perspective paper, we will describe SARS-CoV-2 properties; then we will focus in the relationship between SARS-CoV-2 and aging, discussing the potential roles of comorbidities, inflammaging, immunosenescence, and immune escape. Finally, we will introduce Geroscience as a global approach to treat and prevent the onset and decrease the severity of diseases during aging, notably COVID-19. SARS-CoV-2 properties Coronaviruses are members of the Coronaviridae family. They are divided into Alphacoronavirus and Betacoronavirus that can only infect mammals, and Gammacoronavirus and Deltacoronavirus which mostly infect birds (1). SARS-CoV-2 is a Betacoronavirus (subgroup B Sarbecovirus), enveloped, with a positive single-stranded large RNA that can infect animals and humans. As MERS-CoV and SARS-CoV, it may cause severe diseases and high fatality rate....

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Key Points Question Is plasma amyloid-β 42/40 (Aβ 42/40 ) associated with cognitive decline among community-dwelling older adults with memory concerns? Findings In this cohort study of 483 participants from a randomized clinical trial, low plasma Aβ 42/40 ratio was significantly associated with more pronounced decline in composite cognitive score and Mini Mental State Examination score over time. Meaning In this study, low plasma Aβ 42/40 was associated with more pronounced decline in cognitive function over time, suggesting that this marker may be used to identify people at risk of cognitive decline and as an alternative to more complex and expensive measures.