Sleep-disordered breathing, sleep quality, and mild cognitive impairment in the general population.

There is increasing evidence that sleep disorders are associated with cognitive decline. We, therefore, examined the cross-sectional association of sleep-disordered breathing (SDB), sleep quality, and three types of sleep complaints (difficulties initiating sleep, difficulties maintaining sleep, and early morning awakening) with mild cognitive impairment (MCI) and its subtypes. A group of 1,793 participants (51% men; 63.8 ± 7.5 years) of the population-based Heinz Nixdorf Recall study (total sample n = 4,157) received a screening for SDB and self-report measures of sleep complaints. Group comparisons were used to compare performances among five cognitive subtests. Multivariate logistic regression models were calculated to determine the association of MCI (n = 230) and MCI subtypes (amnestic MCI, n = 120; non-amnestic MCI, n = 110) with SDB severity levels, poor sleep quality, and sleep complaints. Severe SDB (apnea-hypopnea index ≥30/h, n = 143) was not associated with MCI, amnestic MCI, or non-amnestic MCI. Poor sleep quality was associated with MCI (Odds ratio (OR) = 1.40, 95% confidence interval (CI) = 1.02-2.03; fully adjusted) as well as frequently reported difficulties initiating sleep (OR = 1.94, 1.20-3.14), difficulties maintaining sleep (OR = 2.23, 1.27-4.63), and early morning awakening (OR = 2.30, 1.32-4.00). Severe difficulties initiating sleep (OR = 2.23, 1.21-4.13) and early morning awakening (OR = 2.88, 1.45-5.73) were solely associated with the amnestic MCI subtype, whereas, severe difficulties maintaining sleep (OR = 3.84, 1.13-13.08) were associated with non-amnestic MCI. Our results suggest that poor sleep quality, rather than SDB, is associated with MCI. The selective association of difficulties initiating sleep and early morning awakening with amnestic MCI and of difficulties maintaining sleep with non-amnestic MCI might serve as a marker to improve diagnostic accuracy in the earliest stages of cognitive impairment and will be further investigated in our longitudinal examination.

Sleep problems and hospitalization for self-harm: a 15-year follow-up of 9,000 Norwegian adolescents. The Young-HUNT Study.

OBJECTIVES: To investigate the association between sleeping problems in adolescence and subsequent hospital admission for self-harm (SH). DESIGN: Prospective cohort study, linking health survey information on sleep problems to hospital-based patient records. SETTING: Residents of Nord-Trøndelag County, Norway, aged 13-19 years in 1995-97. PATIENTS OR PARTICIPANTS: 10,202 adolescents were invited to participate in the Young-HUNT study; 8,983 (88%) completed the health survey. MEASUREMENTS AND RESULTS: 10% of participants reported difficulties initiating sleep, 4% reported early morning wakening. Ninety-eight participants (27% male) were hospitalized following SH over a mean 12 years follow-up. Difficulties initiating sleep/early morning wakening were associated with increased risk of SH (HR 2.11, 95% CI 1.29-3.46, sex- and age-adjusted) compared with no problems, yet coexistent symptoms of combined anxiety/depression explained most of the association with sleep problems (fully adjusted HR 1.19, 95% CI 0.66-2.16). The HR of combined difficulties initiating sleep/early morning wakening differed in those with and without anxiety/depression at baseline (P interaction = 0.03); among those without caseness symptoms of anxiety/depression it was 5.58 (95% CI 2.02-15.40), while in those with caseness symptoms of anxiety/ depression it was 0.82 (95% CI 0.19-3.44). CONCLUSIONS: Sleep problems are common among Norwegian adolescents. The strong association between sleep problems and subsequent hospitalization for self-harm could mainly be related to coexistent symptoms of anxiety and depression. Prevention of adolescent sleep problems, anxiety and depression should be targeted when seeking to reduce and prevent self-harm.