Sleep Medicine

Poor sleep fragmentation linked to greater lateral gait variability in older adults

In 72 community-dwelling adults (mean age 71), higher objective sleep fragmentation associated with higher probability of lateral step-width variability during a 10-m walk. A 1% higher sleep fragmentation predicted a 6% greater probability of step width variability ≥7.5 cm (95% CI 1.01–1.11). Higher sleep stability and other sleep-quality metrics were inversely associated with lateral displacement. These cross-sectional pilot data suggest sleep is a modifiable risk factor for postural stability, but causality is unproven. 1

Short sleep and poor sleep quality associated with overweight/obesity in professional drivers

Case-control study of 1,200 male Iranian drivers found sleeping ≤7 h linked to higher odds of overweight/obesity (BMI ≥25). Short sleep (≤7 h) had OR 1.319 (95% CI 1.011–1.722) for overweight/obesity; poor sleep quality had OR 1.287 (95% CI 1.014–1.625). Nearly half reported poor sleep quality and one-third slept ≤7 h, supporting sleep as a modifiable occupational risk factor. Findings apply to professional drivers undergoing occupational health evaluation but cannot prove causation. 2

Greater short‑term sleep variability correlates with mood instability in bipolar disorder

In 370 bipolar patients with six months of daily smartphone data, greater sleep variation over 3 days and 1 week correlated with higher mood instability. Effect estimates were large and precise (prior 3 days 1.22, 95% CI 1.19–1.24; prior week 1.40, 95% CI 1.36–1.44; p<0.0001). An inflection point near 8 hours suggested a non-linear sleep–mood relationship. Data are exploratory, patient-reported, and post hoc, so use smartphone monitoring for surveillance rather than causal inferences. 3