Effects Of Telomere Length On The Association Of Early Parent-child Separation With Emotional And Cognitive Development Among Preschool Children

ObjectivesThis study aims to evaluate the sensitive period and cumulative effects of parent-child separation experience on emotional and cognitive development and explore the effects of telomere length on the association of parent-child separation experience with emotional cognitive development and among preschool children,so as to provide theoretical guidance and intervention framework for preventing the lifelong adverse influences of early parent-child separation.MethodsIn May 2021,2729 preschoolers were recruited from 9 kindergartens in Nanling County,Wuhu City through cluster sampling.A total of 2447（1266 boys,51.7%）children completed the questionnaire survey,with an average age of（4.88±0.96）years old.We collected information,such as basic demographic data,parent-child separation experience,family economic status,adverse childhood experiences,parenting styles by parent questionnaire（electronic questionnaire）combined with the caregiver questionnaire.In September 2021,we choose 298 children separated from their parents in the primary and secondary classes participant a special cognitive development survey according to the preliminary questionnaire survey results meanwhile we collected oral swabs,and286 of them completed the cognitive development assessment were included finally.According to the timing and duration of parent-child separation,they were divided into four groups: persistent（0～6 years old）parent-child separation（n=24）,infancy（0～3years old）parent-child separation（n=58）,preschool（4～6 years old）parent-child separation（n=55）and no parent-child separation（n=149）.The Chinese version of the Strengths and Difficulties Questionnaire（SDQ）was used to evaluate the emotional and behavioral development,and the Chinese version of Wechsler Preschool and Primary Scale of Intelligence-the fourth edition（WPPSI-IV）was used to assess the cognitive development of preschool children to obtain children’s full scale intelligent quotient（FSIQ）and verbal comprehension index（VCI）.In addition,oral swabs were collected to detect telomere length（TL）at the same time.The differences in basic demographic information,emotional and behavior problem scores,cognitive development levels（FSIQ and VCI）,and TL among four parent-child separation groups were examined by t-test,one-way analysis or chi-square test.Using multivariate linear regression model to evaluate the associations between parent-child separation type and emotional and behavior problem scores,cognitive development levels（FSIQ and VCI）,and TL among preschool children.The “medeff” command in Stata statistical software was used to test the mediation effect of TL on the associations of parent-child separation with emotional and cognitive development,respectively.ResultsAmong the 286 children included in the special cognitive development survey,134（46.9%）were boys and 152（53.1%）were girls.There were 137 children experienced parent-child separation,of which 42.3%（58/137）separated from both parents during infancy,40.1%（55/137）experienced parent-child separation during preschool period,and 17.5%（24/137）separated from both parents persistently.Children experienced infancy parent-child separation,preschool parent-child separation and persistent parent-child separation had higher peer problems,hyperactivity problems,internalizing problems,externalizing problems and total difficulties scores than those with no parent-child separation experiences.Compared to counterparts with no separation experiences,the cognitive development level of those separated from both parents during infancy,preschool and persistently were significantly lower [FSIQ:（108.63 ±8.50）vs.（103.02 ± 11.12）,（104.07 ± 9.31）,（99.13 ± 9.28）,F=11.086,P<0.001;VCI:（106.13 ± 8.47）vs.（99.48±14.75）,（100.69 ± 11.03）,（97.46 ± 9.95）,F=9.474,P <0.001] and TL were significantly shorter [（0.49±0.14）vs.（0.44±0.15）,（0.43±0.13）,（0.42±0.14）,F=3.853,P<0.05].After adjusted for covariates such as age,gender,BMI,adverse childhood experiences,family economic status and parents’ educational levels,infancy parent-child separation was associated with higher hyperactivity problems（B=0.77,95%CI: 0.15,1.40）,higher internalizing problems（B=0.73,95%CI: 0.64,1.40）,higher externalizing problems（B=1.13,95%CI: 0.29,1.97）,higher total difficulties（B=1.86,95%CI: 0.65,3.08）and lower prosocial behavior scores（B=-0.86,95%CI:-1.54,-0.17）;persistent parent-child separation were associated with higher hyperactivity problems（B=1.07,95%CI: 0.19,1.96）,internalizing problems（B=1.27,95%CI: 0.32,2.22）,externalizing problems（B=1.25,95%CI: 0.07,2.44）,and total difficulties（B=2.52,95%CI: 0.80,4.25）;preschool parent-child separation was not associated with any dimension of emotional and behavioral symptoms.Children undergoing infancy and persistent parent-child separation were related to declined cognitive development levels.Compared with children had no parent-child separation experiences,the FSIQ and VCI of children with parent-child separation during infancy decreased by 3.68 and 3.87,and children with parent-child separation persistently decreased by 6.72 and 5.17,respectively.Preschool parent-child separation was not associated with FSIQ,but was associated with a 4.10 decrease in VCI.Children experienced parent-child separation from both parents were related to shorter TL,whether in infancy（B=-0.05,95%CI:-0.10,-0.00）,preschool（B=-0.07,95%CI:-1.12,-0.02）,or persistently（B=-0.07,95%CI:-0.14,-0.01）.The mediation analysis showed that TL had significant mediating effect in the relationship between parent-child separation experience and FSIQ and TL was estimated to explain 9.3% of the total effect of separation on FSIQ.However,the mediating effect between parent-child separation and internalizing problems,externalizing problems as well as VCI were not observed among preschool children.ConclusionChildren experienced prolonged separation from both parents faced deprivation-specific challenges.There were sensitive period and cumulative effect of associations between early parent-child separation and emotional and cognitive development among preschool children.The levels of multiple dimensions of emotional and behavioral problems were increased,and cognitive development were decreased among children experienced infancy and persistently parent-child separation.Telomere shortening might be a molecular biological mechanism by which early parent-child separation impairs cognitive development in children.Future research should further explore the mediating and moderating factors in child’s environments to inform the development of tailored intervention programs for children affected by prolonged parental absence.