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SLEEP QUALITY IN YOUNG AND MIDDLE AGE-PERIOD IS ASSOCIATED WITH CEREBRAL AMYLOID BURDEN IN COGNITIVELY NORMAL ELDERLY PEOPLE

      Background

      Very little is known for the association between lifetime sleep experience and cerebral beta-amyloid protein (Aβ) deposition, which is the core pathological change related to Alzheimer’s disease process. This study aimed to investigate the relationship of hours of sleep and sleep quality in young and middle age-period with cerebral Aβ burden in elderly individuals with normal cognition.

      Methods

      One hundred and twenty-two cognitively normal old adults (age range: 60-87 years), who participated in the Korean Brain Aging Study for Early Diagnosis and Prediction of Alzheimer’s Disease (KBASE), were included. All subjects underwent comprehensive clinical and neuropsychological assessment, 11Clabelled Pittsburgh Compound B (PiB) positron emission tomography (PET). Through structured clinical interview for each participant, mean hours of sleep and sleep quality were assessed for the following age-periods: before 20 years, in their 20-30s, and 40-50s. Current sleep quality was also assessed by using the Pittsburgh Sleep Quality Index (PSQI). Global cerebral Aβ deposition was defined as mean cortical PiB retention of the cortical regions including the frontal, lateral temporal, lateral parietal and precuneus/posterior cingulate cortices.

      Results

      The poorer sleep quality in all the three younger age-periods was associated with higher mean cortical PiB retention even after controlling for age, gender, apolipoprotein E e4 status, and Hamilton Depression Rating Scale score. In contrast, mean hours of sleep in any young or middle age-period or current sleep quality measured by the PSQI were not related to mean cortical PiB retention.

      Conclusions

      These findings suggest that poorer sleep quality, but not hours of sleep, in young and middle age-period may contribute to increased cerebral amyloid burden in old age.
      TableCorrelation between sleep variables and Pittsburgh Compound B (PiB) retention
      UnadjustedMutivariable Adjusted
      Adjusted for age, gender, apolipoprotein E e4 status, and Hamilton Depression Rating Scale score
      Correlation CoefficientP ValuePartial Correlation CoefficientP Value
      <20y sleep quality0.2460.0060.2240.015
      <20y sleep duration-0.0500.582-0.0300.748
      20-39y sleep quality0.1750.0550.1740.060
      20-39y sleep duration-0.0020.984-0.0130.889
      40-59y sleep quality0.2030.0250.1980.032
      40-59y sleep duration-0.0580.526-0.0850.360
      Total PSQI0.0100.9120.0440.637
      Adjusted for age, gender, apolipoprotein E e4 status, and Hamilton Depression Rating Scale score