title: Stress management reduces intraindividual cortisol variability, while not impacting other measures of cortisol rhythm, in a group of women at risk for breast cancer.
abstract: OBJECTIVE
  The stress hormone cortisol exhibits a diurnal rhythm throughout the day, as well as within person variability. Recent statistical approaches allow for the estimation of intraindividual cortisol variability ("ICV") and a greater ICV has been observed in some mood disorders (major depression, remitted bipolar disorder); however, ICV has not been examined following stress management. In this secondary analyses of an efficacious randomized clinical trial, we examine how ICV may change after cognitive behavioral stress management (CBSM) among healthy stressed women at risk for breast cancer. Second, we concurrently compare other calculations of cortisol that may change following CBSM.
  
  
  METHODS
  Multilevel modeling (MLM) was applied to estimate ICV and to test for a group by time interaction from baseline, post-intervention, to 1 month following CBSM. Forty-four women were randomized to the CBSM; 47 to the comparison group; mean age of the entire group was 44.2 (SD=10.27).
  
  
  RESULTS
  After controlling for relevant covariates, a significant time by group interaction emerged (β estimate=-.070; p<.05), such that CBSM participants demonstrated a lower ICV following CBSM compared to the comparison group. The interaction for cortisol slope and cortisol output (area under the curve) approached significance (β estimates=-.10 and -.062, respectively; p's<.08), while other cortisol outcomes tested were not significantly changed following CBSM.
  
  
  CONCLUSIONS
  ICV may represent a novel index of cortisol dysregulation that is impacted by CBSM and may represent a more malleable within-person calculation than other, widely applied cortisol outcomes. Future research should examine these relationships in larger samples, and examine ICV and health outcomes.
  
  
  BACKGROUND
  NCT01048528.
authors.affiliation: Behavioral Immunology and Endocrinology Laboratory, University of Colorado Denver Anschutz Medical Campus, RC-2, Room 3410A; Mailstop: C268-09, 12700 E. 19th Ave, Aurora, CO 80045, United States. Electronic address: timothy.sannes@ucdenver.edu.
authors.forename: Timothy S
authors.initials: TS
authors.lastname: Sannes
authors.affiliation: American Society for the Prevention of Cruelty to Animals (ASPCA), 424 E. 92nd St, New York, NY 10128-6804, United States.
authors.forename: Emily
authors.initials: E
authors.lastname: Dolan
authors.affiliation: Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N, Seattle, WA 98109, United States.
authors.forename: Denise
authors.initials: D
authors.lastname: Albano
authors.affiliation: Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N, Seattle, WA 98109, United States.
authors.forename: Rachel M
authors.initials: RM
authors.lastname: Ceballos
authors.affiliation: Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N, Seattle, WA 98109, United States.
authors.forename: Bonnie A
authors.initials: BA
authors.lastname: McGregor
mesh_terms: D000328:Adult; D000368:Aged; D019540:Area Under Curve; D001943:Breast Neoplasms / Q000453:epidemiology*; D002940:Circadian Rhythm; D015928:Cognitive Behavioral Therapy; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D007206:Individuality; D008875:Middle Aged; D019964:Mood Disorders / Q000378:metabolism / Q000523:psychology; D012306:Risk; D013315:Stress, Psychological / Q000378:metabolism* / Q000628:therapy*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D006854:Hydrocortisone
keywords: Cortisol; Modeling; Stress; Stress management; Variability