Previous studies have found that social activities are beneficial for the reduction of cognitive decline (CD) in the elderly. However, knowledge regarding the types of social activities that reduce CD in later life is limited. The aim of this study is to examine which type of social activities reduce CD 4 years later among young-old (Y-O) and old-old (O-O) adults. We conducted a secondary analysis using data from cognitively intact adults 65 years of age or older who participated in the Korean Longitudinal Study of Aging (KLoSA). Cognitive function was assessed using the Korean version of the Mini-Mental State Examination (MMSE). We computed CD between 2008 and 2012 by subtracting the Wave 4 MMSE score from the Wave 2 MMSE score. Multivariate linear regression analysis was conducted regarding the effects of social activities on CD after adjusting for age, sex, education, income, marital status, activities of daily living (ADL), instrumental activities of daily living (IADL), chronic diseases, quality of life, depressive symptom, change in depressive symptom, and cognitive functioning at baseline. Subjects who participated in senior citizen clubs or senior centers at baseline had a lower risk of CD 4 years later than those who did not in Y-O adults. Frequent contact with offspring by phone or letters was associated with reduced CD in O-O adults. Frequent face-to-face contact with offspring was positively associated with CD in O-O adults. Participating in two or more formal social activities was associated with reduced CD compared with nonparticipation in O-O adults. Encouraging older adults to participate in senior citizen clubs or to have frequent contacts with adult children by phone or letters may help reduce CD in later life among older adults. Participation in a variety of formal social activities may also have a beneficial effect on preventing CD in older adults.

Background: Despite a relatively large number of studies exploring late-life loneliness, few studies have compared gender differences in the correlates of loneliness of older adults. Thus, we examined the gender differences in correlates of loneliness among community-dwelling older adults. Methods: This study was a secondary analysis of data from a parent study conducted among community-dwelling Koreans 65 years of age or older. Loneliness was measured by the 20-item Revised University of California Los Angeles Loneliness Scale. As potential correlates, demographic, health-related, and social variables were included. Multivariate hierarchical regression analyses were performed separately by gender. Results: Men were more likely to be lonely than women, after controlling for demographic, health-related, and social variables. A social network of family ties and being married were found to be inversely correlated with loneliness in men but not in women. A social network of friendship ties and participation in a variety of community activities were inversely correlated with loneliness in both men and women. Conclusions: A social network of family ties and being married may help reduce late-life loneliness, particularly among men. This study highlights the importance of considering gender differences in the design of strategies for preventing and alleviating late-life loneliness.

The second-order Zeeman effect produces the largest frequency shift among several causes to alter the reference frequency in the optically pumped cesium beam frequency standard. We introduce a novel way to reduce the uncertainties due to the Zeeman effect by adopting a dual servo system, one for stabilizing the current for static magnetic field and the other for normal clock operation. As a result, the combined uncertainty of the second-order Zeeman frequency shift is reduced to 3.2 ×10^-15, which is smaller by one order of magnitude than that without the servo system.

Background/Objectives: The purpose of this cross-sectional study was to investigate gender differences in the associations between living alone and different types of social activities, as well as their relationship to depressive symptoms among community-dwelling older Korean adults. Methods: We conducted a secondary analysis using data from 4481 adults 65 years of age or older who participated in the 2024 Korean Longitudinal Study of Aging. Results: After adjusting for potential confounders, living alone was positively associated with depressive symptoms in older women, but not in men. Contact with close friends was associated with fewer depressive symptoms among both older men and women. Contact with close friends mediated the association between living alone and depressive symptoms in women, but not in men. Conclusions: This study found some evidence of gender differences regarding the links between living alone, different types of social activities, and depressive symptoms among older adults.