title: Perceived stress as a mediator between social constraints and sleep quality among Chinese American breast cancer survivors.
abstract: Previous studies primarily fo c used on how disease- and treatment-related variables affect cancer survivors' sleep quality. Little is known about the impact of the psychosocial factors on their sleep quality. Social constraints are perceived negative social interactions inhibiting one's disclosure. This study examined the association between social constraints and Chinese American breast cancer survivors' (BCS) sleep quality and tested perceived stress as a mediator explaining the association.
  
  
  
  Chinese American BCS (n = 94) were recruited from Southern California. Participants' social constraints, perceived stress, and sleep quality were measured in a questionnaire package.
  
  
  
  Social constraints were associated with higher perceived stress (r = 0.32, p = .002) and poorer sleep quality (r = 0.33, p < .001). Perceived stress was associated with poorer sleep quality (r = 0.47, p < .001). Results from structural equation modeling supported the proposed mediation model, with satisfactory model fit indices (χ2(23) = 33.28, p = .08, comparative fit index = 0.98, Tucker-Lewis index = 0.97, root-mean-square error of approximation = 0.07). The indirect effect from social constraints to poor sleep quality (indicated by the Pittsburgh Sleep Quality Index; PSQI) via perceived stress was significant (β = 0.20; 95% confidence intervals (CI) = 0.06, 0.40). The path coefficient for direct effect from social constraints to PSQI significantly dropped from β = 0.32 (95% CI = 0.11, 0.51) to β = 0.13 (95% CI = -0.12, 0.35) after considering perceived stress as a mediator, suggesting a mediation effect.
  
  
  
  This study implied that social constraints may worsen sleep quality among Chinese American BCS through increasing perceived stress. Interventions to reduce social constraints and perceived stress may improve sleep quality.
authors.affiliation: The Jockey Club School of Public Health and Primary Care, Room 508, Postgraduate Education Centre, Prince of Wales Hospital, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong. nelsonyeung@cuhk.edu.hk.
authors.forename: Nelson C Y
authors.initials: NCY
authors.lastname: Yeung
authors.affiliation: Department of Psychology, University of Houston, Room 126, Heyne Building, 3695 Cullen Boulevard, Houston, TX, 77204-5022, USA.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Ramirez
authors.affiliation: Department of Psychology, University of Houston, Room 126, Heyne Building, 3695 Cullen Boulevard, Houston, TX, 77204-5022, USA. qlu.ucla@gmail.com.
authors.forename: Qian
authors.initials: Q
authors.lastname: Lu
mesh_terms: D001213:Asian; D001943:Breast Neoplasms / Q000401:mortality / Q000523:psychology*; D005260:Female; D006801:Humans; D008875:Middle Aged; D010465:Perception; D012893:Sleep Wake Disorders / Q000523:psychology*; D011795:Surveys and Questionnaires; D017741:Survivors / Q000523:psychology*
keywords: Breast cancer; Chinese American; Perceived stress; Sleep quality; Social constraints