Risk of neurodegenerative diseases in patients with sleep disorders: A nationwide population-based case-control study

Our study aimed to explore the associative relationship between neurodegenerative diseases and sleep disorders. This 15-year retrospective longitudinal nationwide population-based matched case-control study used data extracted from the National Health Insurance Research Database. We evaluated 25,589 patients diagnosed with neurodegenerative diseases between 2000 and 2015 and a matched control of 102,356 patients without neurodegenerative diseases. Sleep disorders were an independent risk factor for the development of neurodegenerative diseases (adjusted odds ratio (OR): 1.794, 95% confidence interval (CI): 1.235–2.268, P < 0.001), with a positive dose-effect relationship (adjusted OR (95% CI): <1 year: 1.638 (1.093–2.872), P < 0.001; 1–5 years: 1.897 (1.260–3.135), P < 0.001; >5 years: 2.381 (1.467–3.681), P < 0.001. Moreover, patients with sleep disorder and comorbid depression had a significantly higher risk of neurodegenerative disorders (adjusted OR: 5.874). Subgroup analysis showed that insomnia was associated with Alzheimer's disease, Pick's disease and essential tremor (adjusted OR (95% CI): 1.555 (1.069–1.965), 1.934 (1.331–2.445) and 2.089 (1.439–2.648), respectively). Obstructive sleep apnea was associated with Parkinson's disease, essential tremor, and primary dystonia (adjusted OR (95% CI): 1.801 (1.239–2.275), 5.523 (3.802–6.977), and 4.892 (3.365–6.178), respectively). Other specific sleep disorders were associated with Pick's disease, Parkinson's disease, essential tremor, and primary dystonia (adjusted OR (95% CI): 8.901 (6.101–11.010), 1.549 (1.075–1.986), 2.791 (1.924–3.531), and 9.114 (6.283–10.506), respectively). Sleep disorders are associated with the subsequent development of neurodegenerative disorders. Moreover, sleep disorder patients with comorbid depression have a higher risk of neurodegenerative diseases.