York University Study Links Sleep Duration to Dementia Risk in Large Global Cohort

Analysis of 69 studies involving nearly 4.5 million people identifies sleep patterns associated with minimized dementia risk

York University researchers in Canada conducted a statistical analysis of pooled data from 69 previous studies. The analysis identified 7 to 8 hours of nightly sleep duration as associated with minimized dementia risk. Participants with less than 7 hours of nightly sleep showed an 18 percent increased dementia risk compared to reference, while those sleeping more than 8 hours demonstrated a 28 percent increased risk. The study included nearly 4.5 million participants who were dementia-free at baseline and tracked for dementia incidence, with all cohort members aged 35 and older. Published in PLOS One (2026), the research does not establish causation between sleep duration and dementia risk. Key limitations include significant variation in data collection methods across the reviewed studies, the absence of sedentary behavior measurements in most studies, and no analysis of whether prolonged sleep indicates early Alzheimer's progression. Future research is needed to examine movement behaviors over time and middle-aged populations. The findings represent statistical associations, not proven cause-effect relationships.

Source: ScienceAlert