title: Partnered sexual activity moderates menstrual cycle-related changes in inflammation markers in healthy women: an exploratory observational study.
abstract: OBJECTIVE
  To examine differences in inflammation markers in sexually active versus abstinent women and observe changes in inflammation markers across the menstrual cycle. Cycle-related immune fluctuations may have evolved to reduce interference with conception. If so, reproductively active (i.e., sexually active) women should show the most variability in cytokine expression.
  
  
  METHODS
  Participants provided serum samples at menses and ovulation (from which cytokines were assayed) and saliva samples at menses and during follicular, ovulation, and luteal phases (from which C-reactive protein [CRP] was assayed). Participants self-reported intercourse frequency during the study.
  
  
  METHODS
  Academic research laboratory.
  
  
  METHODS
  Thirty-two healthy, naturally cycling premenopausal women (sexually active, n = 15; abstinent, n = 17).
  
  
  METHODS
  Observational study.
  
  
  METHODS
  Levels of proinflammatory cytokines (interleukin-6 [IL-6], interferon γ [IFN-γ], tumor necrosis factor-α [TNF-α]), an anti-inflammatory cytokine (interleukin-4 [IL-4]), and a marker of total inflammation (CRP).
  
  
  RESULTS
  Sexually active women had higher levels of all of the immune markers measured, including both pro- and anti-inflammatory cytokines, than abstinent women. Relative to sexually active women, abstinent women had less change across the menstrual cycle in levels of CRP. Among sexually active women, higher intercourse frequency predicted greater midcycle decreases in CRP, IL-6, and IFN-γ and midcycle increases in IL-4.
  
  
  CONCLUSIONS
  Sexual activity may stimulate a complex interaction between pro- and anti-inflammatory cytokines that subsequently drives midcycle declines in inflammation.
authors.affiliation: Kinsey Institute, Indiana University, Bloomington, Indiana; Center for Integrative Study for Animal Behavior, Indiana University, Bloomington, Indiana; Department of Psychology, University of North Carolina at Charlotte, Charlotte, North Carolina. Electronic address: tlorenz@uncc.edu.
authors.forename: Tierney K
authors.initials: TK
authors.lastname: Lorenz
authors.affiliation: Center for Integrative Study for Animal Behavior, Indiana University, Bloomington, Indiana; Department of Biology, Indiana University, Bloomington, Indiana.
authors.forename: Gregory E
authors.initials: GE
authors.lastname: Demas
authors.affiliation: Kinsey Institute, Indiana University, Bloomington, Indiana; Center for Integrative Study for Animal Behavior, Indiana University, Bloomington, Indiana; Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana.
authors.forename: Julia R
authors.initials: JR
authors.lastname: Heiman
mesh_terms: D000328:Adult; D002097:C-Reactive Protein / Q000032:analysis*; D016207:Cytokines / Q000097:blood* / Q000276:immunology; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood* / Q000276:immunology; D008297:Male; D008597:Menstrual Cycle / Q000097:blood* / Q000276:immunology; D012746:Sexual Abstinence; D012725:Sexual Behavior; D012747:Sexual Partners; D055815:Young Adult
chemical_list: D016207:Cytokines; D018836:Inflammation Mediators; D002097:C-Reactive Protein
keywords: C-reactive protein; Inflammation; cytokine; interferon-γ; interleukin-4; interleukin-6; menstrual; sexual activity; tumor necrosis factor-α