TY - JOUR

T1 - Hospital-diagnosed sleep disorders and incident dementia

T2 - a nationwide observational cohort study

AU - Damsgaard, Line

AU - Janbek, Janet

AU - Laursen, Thomas Munk

AU - Erlangsen, Annette

AU - Spira, Adam P.

AU - Waldemar, Gunhild

N1 - Publisher Copyright: © 2022 The Authors. European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.

PY - 2022

Y1 - 2022

N2 - Background and purpose: Several smaller, community-based studies have suggested a link between sleep disorders and dementia with a focus on sleep as a modifiable risk factor for dementia. Studies on neurodegenerative diseases are prone to reverse causation, and few studies have examined the association with long follow-up time. Our aim was to explore the possible association between sleep disorders and late-onset dementia in an entire population. Methods: In a nationwide cohort with 40-year follow-up, associations between hospital-based sleep disorder diagnoses and late-onset dementia were assessed. Incidence rate ratios (IRR) were calculated using Poisson regression. Results: The cohort consisted of 1,491,276 people. Those with any sleep disorder had a 17% higher risk of dementia (IRR 1.17, 95% confidence interval [CI] 1.11–1.24) compared to people with no sleep disorder, adjusted for age, sex, calendar year, highest attained educational level at age 50, and somatic and psychiatric comorbidity. The risk of dementia was significantly increased 0–5 years after sleep disorder diagnosis (IRR 1.35, 95% CI 1.25–1.47), whilst the association after 5 years or more was non-significant (1.05, 95% CI 0.97–1.13). Conclusions: Our findings show an increased short-term risk of dementia following a hospital-based sleep disorder diagnosis, whilst weaker evidence of a long-term risk was found. This could potentially point towards sleep disorders as an early symptom of dementia. Further research is needed to distinguish sleep disorders as an early symptom of dementia, a risk factor, or both.

AB - Background and purpose: Several smaller, community-based studies have suggested a link between sleep disorders and dementia with a focus on sleep as a modifiable risk factor for dementia. Studies on neurodegenerative diseases are prone to reverse causation, and few studies have examined the association with long follow-up time. Our aim was to explore the possible association between sleep disorders and late-onset dementia in an entire population. Methods: In a nationwide cohort with 40-year follow-up, associations between hospital-based sleep disorder diagnoses and late-onset dementia were assessed. Incidence rate ratios (IRR) were calculated using Poisson regression. Results: The cohort consisted of 1,491,276 people. Those with any sleep disorder had a 17% higher risk of dementia (IRR 1.17, 95% confidence interval [CI] 1.11–1.24) compared to people with no sleep disorder, adjusted for age, sex, calendar year, highest attained educational level at age 50, and somatic and psychiatric comorbidity. The risk of dementia was significantly increased 0–5 years after sleep disorder diagnosis (IRR 1.35, 95% CI 1.25–1.47), whilst the association after 5 years or more was non-significant (1.05, 95% CI 0.97–1.13). Conclusions: Our findings show an increased short-term risk of dementia following a hospital-based sleep disorder diagnosis, whilst weaker evidence of a long-term risk was found. This could potentially point towards sleep disorders as an early symptom of dementia. Further research is needed to distinguish sleep disorders as an early symptom of dementia, a risk factor, or both.

KW - dementia

KW - epidemiology

KW - risk factors

KW - sleep apnea syndromes

KW - sleep–wake disorders

U2 - 10.1111/ene.15517

DO - 10.1111/ene.15517

M3 - Journal article

C2 - 35916072

AN - SCOPUS:85137000570

VL - 29

SP - 3528

EP - 3536

JO - European Journal of Neurology

JF - European Journal of Neurology

SN - 1351-5101

IS - 12

ER -