New research in General Psychiatry has uncovered a link between higher levels of daytime light exposure and a lower risk of dementia.
For the study, investigators measured daytime and nighttime light exposure in 87,577 adults who wore accelerometers on their wrists. Over a median follow-up of 8.1 years, 741 participants developed dementia. Average daytime light exposure above 1,000 lux (a moderately bright light level equivalent to an overcast day outdoors) was associated with a 16% reduced dementia risk. Longer exposure to bright daytime light (at least 5,000 lux) was associated with a further reduction in risk.
Less than 0.7 hours per day of bright daytime light was a stronger predictor of dementia than 6 established dementia risk factors. Nighttime light showed no significant association with dementia risk.
“Daytime light exposure may serve as a novel indicator of dementia risk,” said corresponding author Hongliang Feng, PhD, of Guangzhou Medical University, in China
URL upon publication: https://onlinelibrary.wiley.com/doi/10.1002/gps3.70039
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About the Journal
General Psychiatry publishes open access research across psychiatry, mental health, and clinical neuroscience. The journal features original research, systematic reviews, meta-analyses, and case reports spanning biological psychiatry, psychopharmacology, psychiatric genetics, psychotherapy, neuroimaging, and emerging fields including digital psychiatry, computational psychiatry, and artificial intelligence in mental health. Serving psychiatrists, mental health professionals, and interdisciplinary researchers, General Psychiatry advances translational research, biomarker discovery, and evidence-based psychiatric care through contributions bridging international and Chinese perspectives.
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General Psychiatry
Associations between wearable-device-measured daytime and nighttime light exposures and dementia risk: A prospective cohort study
24-Jun-2026