Published papers

© 2020 Elsevier B.V. Objectives: To examine the relationship between multimorbidity and functional limitation, and how social relationships alter that association. Methods: This cross-sectional study used data collected by self-reported questionnaires from adults aged 65 years and older living in a rural area in Japan in 2017. This analysis included complete data from 570 residents. Multimorbidity status was defined as having two chronic diseases exist simultaneously in one individual, and the function status was measured by their long-term care needs. Social relationships were assessed by the Index of Social Interaction and divided into high and low levels. Multiple logistic regression analysis was used to examine the association between social relationships and functional limitation and to assess the role of social relationships in this association. Results: The logistic regression model indicated that the risk of functional limitation was higher in multimorbidity participants than free-of-multimorbidity participants (OR = 2.55, 95% CI = 1.56–4.16). Compared with participants with no multimorbidity and a high level of social relationships, low level of social relationships increased the risk of functional limitation among participants both with and without multimorbidity, with the OR = 7.71, 95% CI = 3.03–19.69 and OR = 3.28, 95% CI = 1.30–8.27, respectively. However, no significant result was found in participants with multimorbidity and a high level of social relationships (P = 0.365). Conclusions: Multimorbidity was associated with functional limitations. However, this association could be increased by a low level of social relationships and decreased by a high level of social relationships.

© 2019 The Royal Society for Public Health Objectives: Social relationships may help in maintaining functional status among older adults. This study examined the types of social relationships that were related to functional status among Japanese community-dwelling older adults. Study design: This is a prospective cohort study. Methods: We used baseline data from 2008 and conducted follow-up surveys six years later. Participants included individuals older than 65 years who lived in a suburban community in Japan. The Index of Social Interaction measure was used to assess multiple elements of social relationships. Two functional status outcomes were set: (1) functional decline and (2) functional decline and mortality. A multiple logistic regression model was used to examine the association between social relationships and functional decline six years later. Results: After controlling for age, sex, family structure and disease status in 2008, poor social curiosity (odds ratio [OR] = 1.31, 95% confidence interval [CI]: 1.02–1.69) and interaction (OR = 2.57, 95% CI: 1.20–5.51) were found to be associated with functional decline. Furthermore, social curiosity (OR = 1.39, 95% CI: 1.14–1.69) and interaction (OR = 2.84, 95% CI: 1.44–5.59) were also associated with the composite outcome. Conclusions: Social curiosity and interacting with others were significantly associated with functional status. Promotion of social interaction may be essential for preventing future need for care.

© 2018 The Author(s). Background: Many reports argue that sleep is important for children's health, learning, and academic performance. The purpose of this longitudinal study was to examine the association between sleep and the development of social competence in infants. Methods: This study was conducted as part of a Japan Science and Technology Agency (JST) project. Caregivers responded to the Japan Children's Study Sleep Questionnaire when children were 18 months old. The interactions of caregivers and children were observed when children were 18, 30, and 42 months old, and rated with the Interaction Rating Scale, which is a measure of social competence. Results: Nocturnal sleep duration of more than 10 h and an earlier bed time than 22:00 were significantly correlated with two trajectory groups (low point and high point transition groups) of children's social competence at 18, 30, and 42 months. Further, total sleep duration of more than 12.25 h and an earlier bed time than 22:00 were significantly correlated with the trajectory of children's social competence at 18, 30, and 42 months. Conclusions: Sleep duration and sleep onset time are important factors in children's development of social competence. Trial registration The ethics committee of the JST approved this study on March 19, 2001. The registration number is 356-1.