Inger H Nordhus

University of Oslo, Oslo, Oslo, Norway

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Publications (11)32.17 Total impact

  • Article: Objective measures of sleep and dim light melatonin onset in adolescents and young adults with delayed sleep phase disorder compared to healthy controls.
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    ABSTRACT: Delayed sleep phase disorder is characterized by a delay in the timing of the major sleep period relative to conventional norms. The sleep period itself has traditionally been described as normal. Nevertheless, it is possible that sleep regulatory mechanism disturbances associated with the disorder may affect sleep duration and/or architecture. Polysomnographic data that may shed light on the issue are scarce. Hence, the aim of this study was to examine polysomnographic measures of sleep in adolescents and young adults with delayed sleep phase disorder, and to compare findings to that of healthy controls. A second aim was to estimate dim light melatonin onset as a marker of circadian rhythm and to investigate the phase angle relationship (time interval) between dim light melatonin onset and the sleep period. Data from 54 adolescents and young adults were analysed, 35 diagnosed with delayed sleep phase disorder and 19 healthy controls. Results show delayed timing of sleep in participants with delayed sleep phase disorder, but once sleep was initiated no group differences in sleep parameters were observed. Dim light melatonin onset was delayed in participants with delayed sleep phase disorder, but no difference in phase angle was observed between the groups. In conclusion, both sleep and dim light melatonin onset were delayed in participants with delayed sleep phase disorder. The sleep period appeared to occur at the same circadian phase in both groups, and once sleep was initiated no differences in sleep parameters were observed.
    Journal of Sleep Research 01/2013; · 3.16 Impact Factor
  • Article: Type D personality is associated with increased prevalence of ventricular arrhythmias in community-residing persons without coronary heart disease.
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    ABSTRACT: Background: Type D personality may be a risk factor for poor outcome in patients with cardiovascular disease. The biological mechanisms underlying this association are poorly understood. The objective of the study was to test the hypotheses that Type D personality is associated with biological markers for sympathetic dysregulation.Design: Cross-sectional community-based study.Methods: Type D personality was evaluated by DS-14 in 450 persons (46% men), aged between 30 and 65 years. From a Holter-recording, (mean length 18.3 hours), long-term heart rate, ventricular arrhythmias, and heart rate variability (HRV) were registered as markers of sympathetic dysregulation. Traditional cardiovascular risk factors, apnoea-hypopnoea index, medication, and anxiety symptoms were adjusted for.Results: Type D persons had higher long-term averaged heart rate (74 vs. 71 beats/min, p = 0.003), but this difference was attenuated and not significant in the multivariate model (p = 0.078)). There was an increased prevalence of complex ventricular ectopy (bigeminy, trigeminy, or non-sustained ventricular tachycardia; 14 vs. 6%, p = 0.005 in multivariate model). HRV indices did not differ significantly between those with or without Type D personality. Anxiety symptoms did not confound these associations.Conclusions: Type D personality is independently associated with a higher likelihood of ventricular arrhythmias, which may be implicated in the increased cardiovascular risk observed in persons with Type D personality.
    European journal of preventive cardiology. 09/2012;
  • Article: Novel cardiovascular risk markers in depression: No association between depressive symptoms and osteoprotegerin or adiponectin in persons at high risk for sleep apnea.
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    ABSTRACT: BACKGROUND: Inflammation is believed to play a role in the pathogenesis of both cardiovascular disease and depressive disorders. We hypothesized that circulating concentrations of the novel inflammatory and cardiovascular biomarkers osteoprotegerin (OPG) and adiponectin as well as high sensitivity C-reactive protein (hsCRP) are associated with the severity of depressive symptoms and presence of major depressive disorder (MDD). METHODS: In a cross-sectional population-derived study (Akershus Sleep Apnea Project) 520 persons underwent clinical examination and venous blood sampling. Medical history was obtained and the participants completed the Beck Depression Inventory (BDI). Structured clinical interviews for axis-I disorders including MDD were performed in a subgroup of 288 participants. OPG and adiponectin concentrations were determined by in-house time-resolved immunofluorometric assays. RESULTS: Despite significant correlation with hsCRP (r=0.162, p<0.001), the sum-score of BDI did not correlate with OPG or adiponectin levels (r=0.011, p=0.811 and r=0.055, p=0.210, respectively). Neither circulating OPG nor adiponectin differed between persons with (n=34) and without (n=246) MDD (median±interquartile range: 1.18 (0.96-1.49) vs. 1.17 (0.93-1.57) ug/l and 7.26 (5.13-9.91) vs. 7.39 (5.23-11.37) mg/l, respectively). LIMITATIONS: Causal considerations are not possible, and results in the sub-group of diagnosed participants need careful interpretation due to small sample size. CONCLUSIONS: hsCRP was independently associated with depressive symptoms, but no association between depression severity or presence of MDD and OPG- or adiponectin concentrations was observed in community-residing persons at high risk for obstructive sleep apnea.
    Journal of affective disorders 08/2012; · 3.76 Impact Factor
  • Article: Circulating cytokine concentrations are not associated with major depressive disorder in a community-based cohort.
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    ABSTRACT: The objective was to test the hypotheses that cytokine levels are elevated in community-residing persons at high risk for obstructive sleep apnea with major depressive disorder (MDD) compared to nondepressive persons and that cytokine levels show stronger correlations with somatic than psychological symptoms of depression. A case-control study within the cross-sectional Akershus Sleep Apnea Project was performed. Two controls matched for age, gender, metabolic syndrome and obstructive sleep apnea were drawn for each case of MDD. Group comparisons revealed no significant difference in the levels of 17 cytokines [interleukin-1β, -2,-4, -5, -6, -7, -8, -10, -12(p70), -13 and -17; tumor necrosis factor-α; interferon-γ; granulocyte colony-stimulating factor; granulocyte-monocyte colony-stimulating factor; macrophage chemoattractant protein-1 and monocyte inhibitory protein-1β] between persons with (n=34) and without MDD (n=68). There was no association between cytokines levels and MDD in multivariate regression analyses. The concentration of interleukin-4 was significantly more positively correlated with psychological than somatic symptoms (r=0.046 vs. -0.143, respectively, P=0.024), while no different correlations were observed for other cytokines. The cytokine levels were not elevated in MDD, and cytokine levels were not more strongly associated with somatic than psychological symptoms of depression. The depression-specific effect on inflammation may be weak in community-based samples with prevalent somatic comorbidity.
    General hospital psychiatry 03/2012; 34(3):262-7. · 2.67 Impact Factor
  • Article: Insomnia, nightmare frequency, and nightmare distress in victims of sexual abuse: the role of perceived social support and abuse characteristics.
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    ABSTRACT: In this study of victims of sexual abuse, the aim was to investigate the role of perceived social support and abuse characteristics in self-reported insomnia, nightmare frequency, and nightmare distress. Four hundred sixty Norwegian victims of sexual abuse completed a questionnaire assessing perceived social support, abuse characteristics, insomnia, nightmare frequency, and nightmare distress. Results show that higher levels of perceived social support were related to lower scores on all symptom outcome measures. Abuse involving oral, genital, or anal penetration was related to more insomnia symptoms. Longer duration of abuse and threatening conducted by the perpetrator were related to higher nightmare frequency, while threats and abuse involving penetration were related to higher degrees of distress associated with nightmares. In conclusion, the present study provides preliminary data indicating that perceived social support may affect the nature of sleep difficulties in sexual abuse victims. Also, more severe forms of sexual abuse are related to higher levels of sleep difficulties.
    Journal of Interpersonal Violence 12/2011; 27(9):1827-43. · 1.64 Impact Factor
  • Article: Sleep disturbances in sexual abuse victims: a systematic review.
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    ABSTRACT: An impressive body of research has investigated whether sexual abuse is associated with sleep disturbances. Across studies there are considerable differences in methods and results. The aim of this paper was to conduct the first systematic review of this area, as well as to clarify existing results and to provide guidelines for future research. We conducted searches in the electronic databases PsycINFO and PubMed up until October 2010 for studies on sleep disturbances in sexually abused samples. Thirty-two studies fulfilled the inclusion criteria (reported empirical data, included sexually abused subjects, employed some form of sleep measurement, English language and published in peer reviewed journals). Across the studies included, sleep disturbances were widespread and more prevalent in sexually abused subjects as compared to in non-abused samples. Symptoms reported more frequently by sexually abused samples included nightmare related distress, sleep paralysis, nightly awakenings, restless sleep, and tiredness. Results were divergent with regards to sleep onset difficulties, nightmare frequency, nocturnal activity, sleep efficiency, and concerning the proportion of each sample reporting sleep disturbances as such. Potential sources of these divergences are examined. Several methodological weaknesses were identified in the included studies. In order to overcome limitations, future researchers are advised to use standardized and objective measurements of sleep, follow-up or longitudinal designs, representative population samples, large sample sizes, adequate comparison groups, as well as comparison groups with other trauma experiences.
    Sleep Medicine Reviews 05/2011; 16(1):15-25. · 6.93 Impact Factor
  • Article: A Norwegian population-based study on the risk and prevalence of obstructive sleep apnea. The Akershus Sleep Apnea Project (ASAP).
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    ABSTRACT: The Berlin Questionnaire (BQ) is a widely used screening tool for obstructive sleep apnea (OSA), but its performance in the general population setting is unknown. The prevalence of OSA in middle-aged adults is not known in Norway. Accordingly, the aims of the current study were to evaluate the utility of the BQ for OSA screening in the general population and to estimate the prevalence of OSA in Norway. The study population consisted of 29,258 subjects (aged 30-65 years, 50% female) who received the BQ by mail. Of these, 16,302 (55.7%) responded. Five-hundred and eighteen subjects were included in the clinical sample and underwent in-hospital polysomnography. Screening properties and prevalence were estimated by a statistical model that adjusted for bias in the sampling procedure. Among the 16,302 respondents, 24.3% (95% confidence interval (CI)=23.6-25.0%) were classified by the BQ to be at high-risk of having OSA. Defining OSA as an apnea-hypopnea index (AHI) ≥5, the positive predictive value of the BQ was estimated to be 61.3%, the negative predictive value 66.2%, the sensitivity 37.2% and the specificity 84.0%. Estimated prevalences of OSA were 16% for AHI≥5 and 8% for AHI≥15. In conclusion, the BQ classified one out of four middle-aged Norwegians to be at high-risk of having OSA, but the screening properties of the BQ were suboptimal. The estimated prevalence of OSA was comparable to previous estimates from general populations in the USA, Australia and Europe.
    Journal of Sleep Research 03/2011; 20(1 Pt 2):162-70. · 3.16 Impact Factor
  • Article: Prevalence of cardiovascular risk factors and concentration of C-reactive protein in Type D personality persons without cardiovascular disease.
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    ABSTRACT: Type D personality is associated with poor cardiovascular outcome in patients with coronary or peripheral arterial disease. Whether Type D personality is associated with cardiovascular risk in persons without overt cardiovascular disease remains unknown. We hypothesized that Type D personality is associated with higher prevalence of traditional cardiovascular risk factors and higher concentration of C-reactive protein. Cross-sectional study. Type D personality was assessed in 453 participants without cardiovascular disease derived from an epidemiological study of obstructive sleep apnoea. An evaluation of obesity, lipid status, diabetes, blood pressure, heart rate, smoking, leisure-time physical activity and high-sensitivity C-reactive protein was performed. Smoking (43% vs. 21%, P < 0.001) and low leisure-time physical activity (<3 hours/week, 57% vs. 40%, P = 0.003) were more prevalent, and heart rate (mean (standard deviation), 75 (10) vs. 71 (9), P = 0.001) and body mass index was higher (29.8 (6.0) vs. 28.4 (4.5) kg/m2, P = 0.009) in Type D compared to non-Type D participants. The total number of risk factors was significantly higher in Type D than non-Type D participants (3.4 (1.3) vs. 3.0 (1.2), P = 0.004). The concentration of C-reactive protein was higher in participants with Type D personality (median, interquartile range 1.6, 0.7-3.4 vs. 1.1, 0.6-2.6, P = 0.047), although not statistically significant after adjustment for possible mediating factors. Among participants at high risk of cardiovascular disease, presence of Type D personality was associated with elevated body mass index and unhealthy behaviour such as smoking and low physical activity, which may have mediated the elevated concentration of C-reactive protein.
    European journal of cardiovascular prevention and rehabilitation: official journal of the European Society of Cardiology, Working Groups on Epidemiology & Prevention and Cardiac Rehabilitation and Exercise Physiology 02/2011; 18(3):504-9. · 2.51 Impact Factor
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    Article: Obstructive sleep apnea, verbal memory, and executive function in a community-based high-risk population identified by the Berlin Questionnaire Akershus Sleep Apnea Project.
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    ABSTRACT: Cognitive functions in community-dwelling adults at high risk of obstructive sleep apnea have not been described and nor are associations between cognitive functions and obstructive sleep apnea severity fully understood. The study aimed to describe verbal memory and executive function in community-dwelling adults identified by the Berlin Questionnaire and to investigate associations between these cognitive domains and different obstructive sleep apnea severity indicators. Among 29,258 age- and gender-stratified persons 30-65 years who received the Berlin Questionnaire by mail, 16,302 (55.7%) responded. From 654 randomly drawn respondents with BQ high risk who were approached for study participation, 290 participants (55.9% males, mean age 48.2 years) were included. Verbal memory was assessed by Rey Auditory Verbal Learning Test and executive function by Stroop test. Obstructive sleep apnea severity indicators were assessed by polysomnography. Mean (standard deviation) verbal learning score was 42.0 (8.9), mean interference time was 31.1 (12.7), median (25th percentile, 75th percentile) apnea-hypopnea index was 7.7 (2.4-22.2), and mean average oxygen saturation was 94.3 (2.0). Verbal learning score was independently associated with average oxygen saturation (β = 0.721, p = 0.025) in multivariate linear regression models adjusted for putative confounders. Interference time was only related to OSA severity indicators in bivariate analyses. Verbal memory and executive function impairments were mild in community-dwelling adults at high risk of obstructive sleep apnea. Average oxygen saturation was the indicator of obstructive sleep apnea severity most strongly associated with cognitive function.
    Sleep And Breathing 02/2011; 16(1):223-31. · 1.84 Impact Factor
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    Article: Patient characteristics and predictors of sleep medication use.
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    ABSTRACT: The objective of this study was to investigate the characteristics of sleep medication users, and their satisfaction with treatment and subjective difficulty with quitting the drugs. A representative sample of 5000 adults in Norway was selected to participate in an epidemiologic study. The data were collected through a postal survey in which a total of 2645 (52.9%) participants responded. Weighted logistic regression was used to explore predictors for the drug pattern use. The prevalence of lifetime, current, and chronic use of sleep medications were 18.8, 7.9, and 4.2%. The use was associated with low socioeconomic status, older age, female sex, and frequent symptoms of sleep disorders, anxiety, and depression. Older age and low perceived control over sleep were the strongest predictors for use and difficulty in quitting sleep medications. Among responders who had ever used sleep medications, 80.3% would prefer a nonpharmacological treatment alternative. It is concluded that consumption of sleep medications is widespread in Norway, and that perception of control over sleep may play a significant role in the drug pattern use. Nonpharmacological treatment is to a small extent implemented in the health care sector.
    International clinical psychopharmacology 03/2010; 25(2):91-100. · 3.35 Impact Factor
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    Article: Sleep problems in general practice: a national survey of assessment and treatment routines of general practitioners in Norway.
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    ABSTRACT: The aim of the current national survey of all general practitioners (GPs) practising in Norway was to explore assessment, treatment practice and perceived efficacy of treatment of sleep problems in general practice. A short questionnaire, including self-report measures of the frequency and routines of treatment and assessment of sleep problems, was sent to all 4049 GPs in Norway, of whom 1465 (36.7%) provided valid responses. The prevalence of sleep problems among patients in general practice was estimated to be 11.2%, of which almost two-thirds were believed to be caused by a medical condition. Anamnestic information and blood tests were the most common assessment of sleep problems, whereas GPs rarely referred patients to all-night polysomnographic recording. Sleep hygiene advices were the most commonly used treatment strategy, whereas hypnotics were believed to have the best short-term efficacy. Antidepressives were considered to be the best option for long-term management of sleep problems. About one-third of the patients were prescribed benzodiazepines or 'Z-drugs' for more than 6 months. This study demonstrates that sleep problems are recognized by GPs, but despite evidence that non-pharmacological treatment is superior in the long-term management of insomnia, the current study shows that hypnotics are still considered by GPs to be the most successful treatment.
    Journal of Sleep Research 09/2009; 19(1 Pt 1):36-41. · 3.16 Impact Factor