Insomnia with objective short sleep duration is associated with longer duration of insomnia in the Freiburg Insomnia Cohort compared to insomnia with normal sleep duration, but not with hypertension

Abstract

Study objectivesTo replicate the association between insomnia with objective short sleep duration and hypertension, type 2 diabetes and duration of insomnia.DesignRetrospective case-control study.SettingDepartment of Psychiatry and Psychotherapy, Medical Center—University of Freiburg.Participants328 patients with primary insomnia classified according to DSM-IV criteria (125 males, 203 females, 44.3 ± 12.2 years).InterventionsN/AMeasurementsAll participants were investigated using polysomnography, blood pressure measurements, and fasting routine laboratory.ResultsInsomnia patients with short sleep duration (< 6 hours) in the first night of laboratory sleep presented with a longer duration of insomnia compared to those with normal sleep duration (≥ 6 hours) in the first night of laboratory sleep. Insomnia patients who were categorised as short sleepers in either night were not more likely to suffer from hypertension (systolic blood pressure of ≥ 140 mm Hg, diastolic blood pressure of ≥ 90 mm Hg, or a previously established diagnosis). Data analysis showed that insomnia patients with objective short sleep duration were not more likely to suffer from type 2 diabetes (fasting plasma glucose level of ≥ 126 mg/dl, or a previously established diagnosis). However, the diabetes analysis was only based on a very small number of diabetes cases. As a new finding, insomnia patients who were categorised as short sleepers in either night presented with increases in liver enzyme levels.ConclusionsThe finding on insomnia duration supports the concept of two distinct sub-groups of insomnia, namely insomnia with, and without, objectively determined short sleep duration. However, our data challenges previous findings that insomnia patients with short sleep duration are more likely to suffer from hypertension.

Genome-wide Analysis of Insomnia (N=1,331,010) Identifies Novel Loci and Functional Pathways

“…Taken together, these results suggest that at a genetic level, insomnia shows partial overlap with sleep duration, but minimal overlap with other sleep-related traits. Consistent short sleep across nights occurs only in a minor part of insomnia patients, even in a clinical sample 42 .…”

Cardiovascular autonomic dysfunction in insomnia patients with objective short sleep duration

“…Given that the consequences associated with this phenotype (insomnia with OSSD) are related with hyperarousal and increased risk of medical morbidity/mortality (Vgontzas et al., ; although, results are not ubiquitous; Johann et al., ), it is posited that there are a number of pathophysiological mechanisms contributing to this association. To date, there are some, albeit limited, findings in participants with insomnia and OSSD, identifying systematic inflammation (i.e., C‐reactive protein; Fernandez‐Mendoza et al., ), HPA‐axis endocrine and metabolic imbalances (i.e., cortisol, glucose; D'Aurea et al., ; Fernandez‐Mendoza et al., ), and hemodynamic dysregulations (i.e., systolic and diastolic blood pressure variability; Johansson, Kronholm, & Jula, ) as possible culprits.…”

Evidence for genetic correlations and bidirectional, causal effects between smoking and sleep behaviours

“…We didn't find similar evidence for causal effects of sleep duration (in hours or as undersleeping) on smoking behaviour, which may seem unexpected. However, insomnia is not necessarily characterized by a short total sleep duration 31 and individuals with a naturally short duration of sleep may not experience fatigue. Our suggestive findings that insomnia causally increases smoking heaviness and decrease the odds of quitting can be informative for developing strategies to improve smoking cessation success.…”