Bidirectional relationship between the pathogenesis of dementia and sleep quality

Eiko N. Minakawa

Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry

Among genetic and non-genetic factors that contribute to the pathogenesis of dementia, non-genetic factors are modifiable and may be novel preventive/therapeutic targets.　Recent clinical epidemiological studies have suggested that unknown non-genetic factors that contribute to dementia may be the key to overcoming the disease.　The prevalence and incidence of dementia have been decreasing in Western countries over the past several decades.　Especially, a significant decrease in dementia prevalence was observed even after adjusting for the confounding of known non-genetic factors.　These studies suggest that novel non-genetic factors may be a clue to the identification of new preventive/therapeutic targets to overcome dementia.
Sleep abnormality is one of the candidates for such non-genetic factors.　Sleep abnormality in patients with dementia was conventionally attributed to dementia pathology involving the brain regions that regulate sleep-wake and circadian rhythms.　Recently, however, a number of studies have suggested that, contrary to the conventional understanding, sleep abnormality may be a risk factor for dementia.　Various research focusing on this bidirectional relationship between dementia and sleep and seeking the potential of sleep as a new target for dementia prevention/treatment has been extensively performed.　In this paper, we outline the current status of such research and discuss future prospective.

Address correspondence to Dr. Eiko N. Minakawa, Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry（4-1-1 Ogawa-Higashi, Kodaira, Tokyo 187-8502, Japan）