title: Moderating effect of apolipoprotein genotype on loneliness leading to depressive symptoms in Chinese older adults.
abstract: OBJECTIVE
  Depressive symptoms, which are both common and heritable, are important indicators of the extent of general well-being and health in old age. Identifying risk factors for depressive symptoms may lead to improved intervention and effective prevention. Both the presence of the apolipoprotein (APOE) genotype and loneliness are associated with later life symptoms of depression, and all three share a neuroendocrine signature, namely altered activity in the hypothalamic-pituitary-adrenal axis. The authors expected a positive association of loneliness with depressive symptoms, a negative link between APOE epsilon2 with depressive symptoms, and a significant genotype-environment interaction between loneliness (the social environment) and APOE epsilon2 on symptoms of depression.
  
  
  METHODS
  This was a cross-sectional observational study.
  
  
  METHODS
  A population-based sample of 979 Chinese people from Taiwan aged 54 years and older was examined.
  
  
  METHODS
  A short-form of the Center for Epidemiologic Studies of Depression Scale was used and the genotype of APOE was obtained.
  
  
  RESULTS
  The interaction between loneliness and APOE epsilon2 was found to be negatively associated with depressive symptoms in adjusted regression models. Loneliness was also positively correlated with symptoms of depression.
  
  
  CONCLUSIONS
  These data suggest that the APOE epsilon2 genotype decreases vulnerability to symptoms of depression in the presence of a social stressor, namely loneliness in this case, and has implications for the enhancement of well-being among older adults. Future studies are needed to delineate the mechanism underlying this gene-environment interaction.
authors.affiliation: Department of Social Work and Social Administration, The University of Hong Kong, Hong Kong, China. klchou@hku.hk
authors.forename: Kee-Lee
authors.initials: KL
authors.lastname: Chou
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D053329:Apolipoprotein E2 / Q000235:genetics*; D044466:Asian People / Q000235:genetics* / Q000523:psychology*; D003863:Depression / Q000235:genetics* / Q000523:psychology*; D005260:Female; D005838:Genotype; D006801:Humans; D008132:Loneliness / Q000523:psychology*; D008297:Male; D008875:Middle Aged; D012307:Risk Factors
chemical_list: D053329:Apolipoprotein E2