Table 3.

Large longitudinal studies in cognitively normal adults evaluating sleep disturbances as a risk factor for later cognitive decline or dementia

Reference	Sample	Duration	Methods	Sleep disturbance a risk factor (Yes/No)	Key finding
Potvin et al., 2012 (Potvin et al., 2012)	n = 1664	1 year	Self-report	Yes	Increased incidence of cognitive impairment (MMSE)
Keage et al., 2012 (Keage et al., 2012)	n = 2012	10 years	Self-report	Yes	Obtaining 6.5 h or less of nighttime sleep and excessive daytime sleepiness were associated with an increased risk of cognitive decline
Lim et al., 2013 (Lim et al., 2013a)	n = 737	6 years	Actigraphy	Yes	Sleep fragmentation was associated with a 22% increase in annual rate of cognitive decline, and increased risk (1.5-fold) of AD compared to those with the lowest levels of sleep fragmentation
Yaffe et al., 2015 (Yaffe et al., 2015)	n=179738	8 years	Medical records	Yes	Diagnosis of a sleep disorder was associated with a 27% increased risk of developing dementia
Luojus et al., 2017 (Luojus et al., 2017)	n = 2386	20 years	Self-report	Yes	Sleep disturbances at baseline had an increased risk of dementia (risk ratio 1.58)
Suh et al., 2018 (Suh et al., 2018)	n = 2238	4 years	Self-report	Yes	Long sleep latency, long sleep duration and late mid sleep time had increased risk of cognitive decline
Ohara et al., 2018 (Ohara et al., 2018)	n = 1517	10 years	Self-report	Yes	Short (< 5 h) and long (> 10 h) daily sleep duration and hypnotic use were associated with higher incidence rates of dementia and allcause mortality
Lysen et al., 2018 (Lysen et al., 2018)	n = 4835	8.5 years	Self-report	No	Poorer subjective sleep quality was not associated with an increased risk of dementia
Sindi et al., 2018 (Sindi et al., 2018)	n = 3210	3–11 years	Self-report	Yes/No	Late-life sleep disturbances were associated with poorer cognition. Midlife general sleep problems were not associated with late-life MMSE performance
Burke et al., 2019 (Burke, 2019)	n = 6782	11 years	Self-report	Yes	Sleep disturbance was associated with eventual AD development, at same rate for APOEε4+ and non-carriers
Tsai et al., 2020 (Tsai et al., 2020)	n = 3978 diagnosed with obstructive sleep apnea (OSA); n = 15912 healthy controls	Up to 16 years	Medical records	Yes	OSA was associated with increased risk of AD (hazard ratio 2.12). Treated OSA had lower risk of AD.