title: Curvilinear relationship between depression and unprotected sexual behaviors among men who have sex with men.
abstract: BACKGROUND
  The relationship between depressive symptomatology and risky sexual behaviors has been controversial in literature.
  
  
  OBJECTIVE
  The current study aims to reexamine the relationship between depression and sexual behaviors among men who have sex with men (MSM) using different sets of analytical assumption.
  
  
  METHODS
  Six hundred twenty MSM were recruited in a lesbian, gay, bisexual, and transgender community center in Taiwan to participate in a cross-sectional survey. An additional variable of squared depressive symptomatology was used to detect nonlinearity between depressive symptomatology and logit-transformed unprotected anal intercourse (UAI) and unprotected oral sex (UOS). Multivariable logistic regression was applied to further estimate the relationship among the three variables.
  
  
  METHODS
  Depressive symptomatology was measured by the Beck Depression Inventory (BDI), UAI, and UOS.
  
  
  RESULTS
  Depressive symptomatology had a nonlinear relationship with unprotected anal and oral sex. While linear BDI scores of MSM were not associated with unprotected sexual behaviors in the logistic model, their scores were significantly associated with unprotected sexual behaviors in the model that included both the linear (UAI, odds ratio [OR] = 1.087; P < 0.01; UOS, OR = 1.099, P < 0.01) and quadratic BDI scores (UAI, OR = 0.998, P < 0.01; UOS, OR = 0.997, P < 0.01). The relationship between BDI scores and the probability of unprotected sexual behaviors corresponded to an inverted U-shaped curve, as opposed to a straight line.
  
  
  CONCLUSIONS
  Our findings suggest that depressive symptomatology has a significant curvilinear relationship with unprotected sexual behaviors. MSM with moderate levels of depression may be at elevated risk of engaging in unprotected sexual behaviors in comparison to their peers who exhibit either significantly higher or lower depression scores.
authors.affiliation: School of Social Work, University of Washington, Seattle, WA, USA.
authors.forename: Cheng-Shi
authors.initials: CS
authors.lastname: Shiu
authors.forename: Yen-Chin
authors.initials: YC
authors.lastname: Chen
authors.forename: Po-Chia
authors.initials: PC
authors.lastname: Tseng
authors.forename: An-Chun
authors.initials: AC
authors.lastname: Chung
authors.forename: Meng-Tzu
authors.initials: MT
authors.lastname: Wu
authors.forename: Su-Ting
authors.initials: ST
authors.lastname: Hsu
authors.forename: Nai-Ying
authors.initials: NY
authors.lastname: Ko
mesh_terms: D000328:Adult; D001727:Bisexuality / Q000523:psychology / Q000706:statistics & numerical data; D003430:Cross-Sectional Studies; D003863:Depression / Q000453:epidemiology*; D005260:Female; D018451:Homosexuality, Male / Q000523:psychology / Q000706:statistics & numerical data*; D006801:Humans; D016015:Logistic Models; D008297:Male; D012309:Risk-Taking; D012725:Sexual Behavior / Q000523:psychology / Q000706:statistics & numerical data*; D013624:Taiwan / Q000453:epidemiology; D047568:Unsafe Sex / Q000523:psychology / Q000706:statistics & numerical data*; D055815:Young Adult
keywords: Curvilinear Relationships; Depression; MSM; Risky Sexual Behaviors