The Relationship Between Sleep And Physical Frailty Among Chinese Community-dwelling Older Adults:depression As A Mediator And Its Interaction With Sleep

ObjectivesTo explore the relationship between sleep quality and frailty;to explore depression as a mediator between sleep quality and frailty;to explore the additive interaction between depression and sleep quality on frailtyMethodsA total of 936 community-dwelling adults aged? 60 years were recruited from 22 communities between June and September 2018 in Jinan,Shandong.Sleep quality,depression symptoms and frailty were measured by the Pittsburgh Sleep Quality Index(PSQI),the 5-item Geriatric Depression Scale(GDS-5)and the Physical Frailty Phenotype,respectively.A self-designed questionnaire was used to collect socio-demographic data and chronic diseases,and the Short Portable Mental Status Questionnaire(SPMSQ)was used to assess cognitive function.Data were analyzed with SPSS 21.0.Descriptive analysis,F-tests,chi-square tests,ordinal logistic regression and binomial logistic regression were used to describe and analyze dataThe z-test was conducted to verify whether the mediating effect of depressive symptoms between sleep quality and frailty was significant.The 3 additive interaction indicators:(1)the relative excess risk due to interaction(RERI);(2)the attributable proportion due to interaction(AP);and(3)the synergy index(S)were to verify the additive interaction between sleep quality and depressive symptoms on frailty.Results1.Of the 936 older adults,33.9%(n=317)had poor sleep quality and 10.4%(n=97)had depressive symptoms.The prevalence was 3.8%(n=35)for frailty,52.0%(n=487)for prefrailty,and 44.2%(n=414)for robustness.2.Chi-square and F tests showed that,prefrail and frail older adults reported higher prevalence of poor sleep quality(P<0.001)and depressive symptoms(P<0.001).Furthermore,prefrail and frail older adults were more likely to be older(P<0.001),have less years of schooling(P<0.001),have no partner(P=0.010),have cognitive impairment(P<0.001),and have chronic diseases(P<0.001).3.The multiple variable logistic regression analyses showed that poor sleep quality was associated with physical frailty(OR=1.79,P<0.001)and with depression(OR=5.14,P<0.001),and depression was associated with physical frailty(OR=2.99,P<0.001).With further adjustment for depressive symptoms,the association between poor sleep quality and physical frailty was attenuated but persisted(OR=1.56,P=0.003).The z-test(z=3.73,P<0.05)further confirmed the significant mediating effect of depressive symptoms on the relationship between sleep quality and physical frailty.4.The ordinal logistic regression analyses showed that,older participants jointly exposed to poor sleep quality and depressive symptoms had higher risk of physical frailty(OR=5.92;95%CI:3.30-10.62)than those with poor sleep quality(OR=1.45;95%CI:1.06-1.97)or with depressive symptoms(OR=1.84;95%CI:0.87-3.92)alone,respectively.The RERI,AP and S were 3.63(95%CI:0.03-7.23),0.61(95%CI:0.29-0.93)and 3.82(95%CI:1.05-13.87),respectively.The results indicate an additive interaction effect of poor sleep quality and depressive symptoms on physical frailty.Conclusions1.Frailty of the elderly in communities requires the attention of individuals,families,communities and society.2.Poor sleep quality is associated with frailty.3.Depressive symptoms mediate the relationship between sleep quality and physical frailty.4.Comorbid depressive symptoms and poor sleep quality have an additive interaction on frailty.