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Aim: The study aimed to identify social factors predicting improvement of frailty in community‐dwelling older adults after 2 years using a population‐based cohort study. Methods: We analyzed data from the 2016 and 2018 Korean Frailty and Aging Cohort Study. The participants of this study were 1428 community‐dwelling older adults aged 70–84 years who were recruited from 10 medical centers across different regions. Frailty was measured using the five‐item FRAIL scale, which evaluates fatigue, resistance, ambulation, illness and weight loss. Multilevel logistic regression analysis was used to examine baseline social factors that predict frailty improvement after 2 years by frailty status. Results: In frail older adults, higher participation in social activities (odds ratio [OR] 1.17, 95% confidence interval [CI] 1.02–1.34) was significantly associated with frailty improvement. In pre‐frail older adults, there were no significant social factors predicting the improvement of frailty status; however, other modifiable factors such as high and moderate levels of physical activity (OR 1.17, 95% CI 1.07–1.28, OR 1.13, 95% CI 1.03–1.25, respectively) and low depressive symptoms (OR 0.88, 95% CI 0.84–0.91) were associated with pre‐frail improvements. High levels of physical activity (OR 1.16, 95% CI 1.02–1.33) were also associated with improvements of frailty. Conclusions: Different strategies depending on the level of frailty are necessary to improve frailty status. Timely and appropriate interventions can promote frailty improvement and prevent negative health outcomes in community‐dwelling older adults. Geriatr Gerontol Int 2021; 21: 465–471. [ABSTRACT FROM AUTHOR]

Neuregulin-1 (NRG-1) is a ligand of the epidermal growth factor receptor (erbB), and its interaction involves activation of the glutamatergic N-methyl-Daspartate receptor, which increases the expression of the β2 subunit of the γ- aminobutyric acid receptor and subunits of the nicotinic acetylcholine receptor. In the dentate gyrus of 14-month-old Tg2576 mice, NRG-1 was strongly expressed compared with age-matched controls. The supernatant of oligomeric amyloid β peptide (Aβ42)-treated glial cells enhanced the Aβ42;-induced cytotoxic effects, but the expression of Fas ligand and tumor necrosis factor-related apoptosis-inducing ligand in microglial cells was not changed upon cytotoxic treatment. This suggests that the oligomeric form of Aβ42 toxicity is not related to apoptosis, which is mediated by cell-to-cell interaction. During the 24-h incubation, the secretion of the soluble form of NRG-1 was increased, but interleukin 6 secretion was not changed. Further, soluble NRG-1 increased Aβ42-induced toxicity. In conclusion, soluble NRG-1 significantly enhanced oligomeric Aβ42-induced toxicity through the activation of endoplasmic reticulum stress by the increase of a phospho-translation initiation factor 2 alpha (p-eIF2α).