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Insomnia with objective short sleep duration is associated with cognitive impairment

Insomnia with objective short sleep duration has been previously associated with adverse cardiometabolic health outcomes as well as poorer cognitive performance in otherwise noncognitively impaired adults.
However, studies demonstrating an increased prevalence of cognitive impairment in this insomnia phenotype are lacking.

Researchers have analyzed data from Penn State Adult Cohort ( N = 1,524; 48.9 ± 13.4 years; 53.4% women ).
Self-reported sleep difficulty was defined as normal sleep ( n = 899 ), poor sleep ( n = 453 ), and chronic insomnia ( n = 172 ). Objective short sleep duration was defined as less than 6-h of sleep, based on in-lab, 8-h polysomnography.
Cognitive impairment ( n = 155 ) and possible vascular cognitive impairment ( pVCI, n = 122 ) were ascertained using a comprehensive neuropsychological battery.
Analyses was adjusted for age, sex, race, education, body mass index, apnea / hypopnea index, smoking, alcohol, psychoactive medication, and mental and physical health problems.

Participants who reported poor sleep or chronic insomnia and slept objectively less than 6 hours were associated with a 2-fold increased odds of cognitive impairment ( OR = 2.06, 95% confidence limits [ CL ] = 1.15–3.66 and OR = 2.18, 95% CL = 1.07–4.47, respectively ) and of vascular cognitive impairment ( OR = 1.94, 95% CL = 1.01–3.75 and OR = 2.33, 95% CL = 1.07–5.06, respectively ).

Participants who reported poor sleep or chronic insomnia and slept objectively more than 6 hours were not associated with increased odds of either cognitive impairment ( OR = 0.72, 95% CL = 0.30–1.76 and OR = 0.75, 95% CL = 0.21–2.71, respectively ) or vascular cognitive impairment ( OR = 1.08, 95% CL = 0.42–2.74 and OR = 0.76, 95% CL = 0.16–3.57, respectively ).

In conclusion, insomnia with objective short sleep duration is associated with an increased prevalence of cognitive impairment, particularly as it relates to cardiometabolic health ( i.e. vascular cognitive impairment ).
These data further support that this insomnia phenotype may be a more biologically severe form of the disorder associated with cardiovascular, cerebrovascular, and neurocognitive morbidity. ( Xagena )

Fernandez-Mendoza J et al, Sleep 2020; Online ahead of print

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