Combined Effect of Daily Physical Activity and Social Relationships on Sleep Disorder Among Older Adults: A Cross-Sectional Study Based on Data From The Kasama Study

Abstract

\n Background: This cross-sectional study investigated whether the daily physical activity of older adults, combined with social relationships, is associated with the risk of sleep disorder. Further, it determined whether a high level of one variable with a low level of the other leads to a significantly lower risk of sleep disorder than low levels of both. Methods: The sample comprised 988 community-dwelling older Japanese adults (mean age: 73.1 ± 5.5 years). The level of daily physical activity and range of social relationships were assessed using the Physical Activity Scale for the Elderly and the Lubben Social Network Scale, respectively. The Pittsburgh Sleep Quality Index was used to assess sleep disorder. To test linear trends and the combined effect of the two variables, both variable values were divided into tertiles. To test the combined effects, medians were calculated for the respective scores, based on which the participants were categorized into the following groups: (1) inactive with a narrow range of social relationships (n = 307), (2) inactive with a wide range of social relationships (n = 183), (3) active with a narrow range of social relationships (n = 205), and (4) active with a wide range of social relationships (n = 293). After adjusting for potential confounders, a logistic regression analysis was conducted. Results: Participants who were more physically active (odds ratio [OR]: 0.694, 95% confidence interval [CI]: 0.484–0.997) and those with a wide range of social relationships (OR: 0.690, 95% CI: 0.481–0.988) showed a lower prevalence of sleep disorder than those in the first tertile; these effects were independent of each other. The combined effect analysis revealed that the active group with a wide range of social relationships showed a significantly lower prevalence of sleep disorder (OR: 0.585, 95% CI: 0.404–0.847) than the inactive group with a narrow range of social relationships.Conclusions: Our findings suggest that being physically active with a wide range of social relationships is favorably associated with sleep quality. However, a high level of one variable with a low level of the other is inefficient in improving sleep quality among older adults.