title: Gender differences in age-related changes in HPA axis reactivity.
abstract: Possible differences between men and women in age-related patterns of hypothalamic-pituitary-adrenal (HPA) axis response to challenge were examined to test the hypothesis that women show greater age-related increase in HPA axis reactivity to challenge. Twenty-six younger subjects, 9 men and 17 women, ages 22-26 and 14 older subjects, 7 men and 7 women, ages 67-88 participated in the study. Patterns of change in salivary "free" cortisol were measured in response to a standardized, 30-minute cognitive challenge, administered individually to each subject beginning at 1600 h. Consistent with previous research, there was a significant main effect for age with respect to baseline cortisol: older age was associated with higher baseline cortisol (P = <0.001). Results also provide support for the hypothesized age-by-gender interaction with respect to patterns of response to challenge. There was a significant interaction with respect to maximum percentage increase over baseline (P < 0.002): among younger adults, the men exhibited greater increases whereas among the older adults, the women exhibited greater increases. A similar, though only marginally significant pattern was seen for total area under the response curve (P = 0.07). Repeated measures ANOVA confirmed the gender-by-age differences in the patterns of response (P = 0.01 for time*age*gender interaction).
authors.affiliation: Division of Geriatrics, UCLA School of Medicine, Los Angeles, CA 90095-1687, USA. tseeman@mednet.ucla.edu
authors.forename: T E
authors.initials: TE
authors.lastname: Seeman
authors.forename: B
authors.initials: B
authors.lastname: Singer
authors.forename: C W
authors.initials: CW
authors.lastname: Wilkinson
authors.forename: B
authors.initials: B
authors.lastname: McEwen
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D019540:Area Under Curve; D003071:Cognition / Q000502:physiology; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology*; D008297:Male; D012463:Saliva / Q000378:metabolism; D012727:Sex Characteristics; D013315:Stress, Psychological / Q000503:physiopathology*
chemical_list: D006854:Hydrocortisone