Does Sleep Affect Cognitive Decline?

To determine whether variations in sleep parameters affect risk for cognitive decline, researchers conducted a prospective cohort study involving 2893 Korean adults (age, ≥60 years). Of these participants, 2238 had normal cognition and 655 had mild cognitive impairment.

Sleep parameters included sleep latency (the time to fall asleep), midsleep time (the midpoint between bedtime and wake time), and sleep duration. Cognition status was determined by consensus criteria. Values of sleep variables and cognitive status were determined at baseline and at 4-year follow-up.

Among those with normal cognition at baseline, the risk at follow-up for cognitive decline increased by 40% with long sleep latency (>30 minutes) versus average latency, increased…