Depressive symptom as a mediator of the influence of self-reported sleep quality on falls: a mediation analysis.

It is well known that sleep quality was associated with falls. This study aimed to examine whether the presence of depressive symptoms mediate the association of self-reported sleep quality with falls. Data of community-based study including 4,579 adults aged 60 years or older were analyzed. Information regarding sleep quality and falls was self-reported by participants using pre-designed questionnaires. The nine-item Patient Health Questionnaire (PHQ-9) without the sleep item was used to assess the presence of depressive symptoms. A bootstrapping approach was performed to explore whether the relationship between self-reported sleep quality and falls was partially mediated by depressive symptoms. The mediator was considered significant if the 95% confidence interval (CI) did not include 0. Older adults with poor sleep quality had higher odds of falls than their counterparts with normal sleep. In the equation regressed falls on self-reported sleep quality and PHQ-9 score, the association between self-reported sleep quality and falls disappeared. Depressive symptoms partially mediated the association between self-reported sleep quality and falls based on the significance of indirect effect (β = 0.15, 95% bootstrap CI = 0.08, 0.22). The presence of depressive symptoms might partially mediate the association of self-reported sleep quality with falls among older adults.