title: Sleep characteristics as predictor variables of stress systems markers in insomnia disorder.
abstract: This study investigates the extent to which sleep characteristics serve as predictor variables for inflammatory, hypothalamic-pituitary-adrenal and autonomic systems markers. Twenty-nine participants with a diagnosis of insomnia disorder based on the Diagnostic Statistical Manual of Mental Disorders, Fifth Edition (age 25.3 ± 1.6 years, insomnia duration 6.6 ± 0.8 years) and 19 healthy control sleepers (age 25.4 ± 1.4 years) underwent a 2-week at-home evaluation keeping a sleep diary and wearing an actigraph, followed by a visit to the Research Center to measure blood pressure, and collect blood and urine samples. The actigraphy- and diary-based variables of sleep duration, sleep-onset latency, wake after sleep onset and sleep fragmentation/number of night-time awakenings were averaged and entered as dependent variables in regression analyses. Composite scores were calculated for the autonomic (blood pressure, norepinephrine), inflammatory (monocyte counts, interleukin-6, C-reactive protein) and hypothalamic-pituitary-adrenal systems (cortisol), and used as predictor variables in regression models. Compared with controls, individuals with insomnia had a shorter sleep duration (P < 0.05), and a higher hypothalamic-pituitary-adrenal and inflammatory composite score (P < 0.05). The higher inflammatory score was mainly due to higher circulating monocytes (P < 0.05), rather than differences in interleukin-6 or C-reactive protein. In persistent insomnia disorder, cortisol is upregulated and associated with actigraphy- and diary-based wake after sleep onset, suggesting that wake after sleep onset may serve as a marker to identify individuals at increased risks for disorders associated with a hyperactive hypothalamic-pituitary-adrenal system. The absence of autonomic and pro-inflammatory changes (interleukin-6, C-reactive protein), despite a substantial decrease in actigraphic sleep duration, may relate to a higher resilience to the adverse biological consequences of insomnia in this young age group.
authors.affiliation: Harvard School of Dental Medicine, Boston, MA, USA.
authors.forename: Samantha
authors.initials: S
authors.lastname: Floam
authors.affiliation: Stanford University, Stanford, CA, USA.
authors.forename: Norah
authors.initials: N
authors.lastname: Simpson
authors.affiliation: Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
authors.forename: Emese
authors.initials: E
authors.lastname: Nemeth
authors.affiliation: Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Scott-Sutherland
authors.affiliation: Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
authors.forename: Shiva
authors.initials: S
authors.lastname: Gautam
authors.affiliation: Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
authors.forename: Monika
authors.initials: M
authors.lastname: Haack
mesh_terms: D056044:Actigraphy; D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000032:analysis* / Q000097:blood / Q000652:urine; D001794:Blood Pressure / Q000502:physiology; D002097:C-Reactive Protein / Q000032:analysis; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology; D007249:Inflammation / Q000503:physiopathology; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000166:cytology; D009638:Norepinephrine / Q000652:urine; D010913:Pituitary-Adrenal System / Q000503:physiopathology; D012890:Sleep / Q000502:physiology*; D007319:Sleep Initiation and Maintenance Disorders / Q000097:blood / Q000503:physiopathology* / Q000652:urine; D013312:Stress, Physiological / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult
chemical_list: D015415:Biomarkers; D015850:Interleukin-6; D002097:C-Reactive Protein; D006854:Hydrocortisone; D009638:Norepinephrine
keywords: actigraphy; blood pressure; hypothalamic-pituitary-adrenal; inflammation; stress