Social Isolation,Loneliness And Cognitive Function Among Chinese Older Adults

Most studies exploring the association between social isolation,loneliness and cognition among older adults tend to focus on Western populations.The aim is to examine the association of social isolation,loneliness and cognitive function among Chinese older adults.Study 1 was a longitudinal study based on the China Health and Retirement Longitudinal Study(CHARLS),while Study 2 was a cross-sectional study based on cognitive tasks.Study 1 used two waves of data(2011 and 2015)from CHARLS and analyses were restricted to those respondents aged 50 and older.Social isolation was measured by Steptoe social isolation index.Loneliness was assessed with one single item included in the Centre for Epidemiological Studies Depression Scale(CESD): “In the last week,how often did you feel lonely?”.Follow-up cognitive function constructed by episodic memory and mental status were obtained for 7,850 participants(mean age = 60.97,SD= 7.32;male,50.7%).Lagged dependent variable models adjusted for confounding factors were used to evaluate the association between baseline isolation,loneliness,and follow-up cognitive function.Social isolation was significantly associated with followup cognitive function(episodic memory: β=-0.04,p<0.001;mental status: β=-0.02,p= 0.012).By contrast,no significant association was found between loneliness and follow-up episodic memory(β=-0.02,p = 0.132)and mental status(β=-0.02,p =0.083).A significant interaction between isolation and loneliness was found for mental status decline(β = 0.03,p = 0.029).The data of study 2 came from cognitive tasks conducted in 94 communitydwelling older adults in Tianjin(mean age = 66.37,SD = 5.40;male,37.2%).Loneliness was measured by UCLA loneliness Scale.Social isolation was assessed by social network questionnaire.Four cognitive tasks(two-choice task,Stroop color and word test,attentional network task and N-back task)and the Mini Mental State Examination(MMSE)were used to assess cognitive function.Linear regression models adjusted for confounding factors were used to evaluate the association between social isolation,loneliness,and cognitive performances.Neither social isolation nor loneliness was significantly associated with reaction time of Stroop color and word test,twochoice task performance,attentional network task performance,N-back task performance,and MMSE score.Loneliness(β= 0.30,p = 0.011)rather than social isolation(β = 0.18,p = 0.074)was significantly associated with the accuracy of Stroop color and word test.No significant interaction between isolation and loneliness was found.Study 1 found that social isolation rather than loneliness was significantly associated with cognition decline among a national representative sample in China.In Tianjin community-dwelling older adults,loneliness rather than social isolation was significantly associated with the accuracy of Stroop color and word test.Totally,impoverished social relationships are harmful to cognitive function among Chinese older adults.These findings expand our knowledge about the impact of poor social relationships on the cognitive functions in non-Western countries.Efforts to reduce isolation may have substantial benefits in terms of cognition among older adults in China.