The Relationship Of Migration And The Risk Of Depressive Symptoms Based On Marginal Structure Model Among The Middle-Aged And The Elderly In China:the Mediating Effect Of Social Isolation

ObjectiveChina has experienced an unprecedented process of population aging and population migration.The situation of depressive symptoms in order adults presents a serious public health challenge.We use the marginal structure model to effectively control the time-dependent confounding variables.We conducted the current study among Chinese older adults aged 45 or over to understand the effect of migration and social isolation on depressive symptoms,explore the mediating effect of social isolation on the association of migration and depressive symptoms,and detect gender,age,place of residence and education level differences.We aim to provide an evidence-based guidance for decreasing the incident of depressive symptoms,improving the quality of life among older adults,and implementing policy of gerontology.MethodsData used were derived frorm the 2011 wave(donated as baseline data),2013 wave(donated as first follow-up)and 2015 wave(donated as follow-up endpoint)of the China Health and Retirement Longitudinal Study(CHARLS).Older adults aged 45 or over with complete data and no depressive symptoms at baseline were included in our study.The 10-item Center for Epidemiological Studies Depression Scale(CESD-10)was used to measure depressive symptoms,and a score of high than 10 was measured as depressive symptoms.Move out of the place of residence for more than 6 months was defined as migration.Social isolation was measured by current marital status or living arrangement,the frequency of contact with family members,friends and children and organizational participation.The total score ranges from 0 to 5,with a score of less than or equal to 2 denoting social isolation.T-test and chi-square test were used for basic statistical description,while marginal structural model(MSMs)was used to control possible confounding variables.Weighted logistic regression analysis was used to explore the effect of migration and social isolation on depressive symptoms,explore the possible mediating effect of social isolation on the association of migration and depressive symptoms.All analyses were stratified by gender,age,place of residence and educational level as well.Resu tsA total of 10,965 people aged 45 and above were included in this study.2,845 people(31.93%)had migrated.After 4 years of follow-up,2,078 people(24.27%)developed depressive symptoms.Older adults who were women,farmers,older age,had low education,poor self-rated health status,poor ability in daily life,and mild cognitive impairment are more likely to develop depressive symptoms.The results of weighted logistic regression analysis showed that migration increased depressive symptoms incidence risk(odds ratio(OR)＝1.18,95%confidence interval(CI):1.01-1.3 8).After the inclusion of mediators,migration had no direct effect on depressive symptoms,OR=1.04(95%CI:0.81-1.31).At the same time,migration will increase the incident of social isolation(OR=1.29,95%CI＝1.07-1.56)and Social isolation will increase the incident of depressive symptoms(OR=l.38,95%CI=1.05-1.83)as well.It indicates that migration increase the incident of depressive symptoms through the intermediary of social isolation completely.ConclusionsMigration is an important risk factor for depressive symptoms among middle-aged and old people in China.Meanwhile,social isolation plays a completely mediating role on the association of migration and depressive symptoms.More attention should be paid to the migration elderly to decrease the incidence of depressive symptoms.