SLEEP 2011 Abstract Supplement

B. Clinical Sleep Science II. Sleep Disorders – Circadian Rhythms
0473
CHRONIC SLEEP RESTRICTION COMBINED WITH
CIRCADIAN MISALIGNMENT LEADS TO INADEQUATE
INSULIN SECRETION RESPONSE TO MEALS IN YOUNG
AND OLDER HEALTHY ADULTS
Buxton O 1,2 , Wang W 1,2 , Cain SW 1,2 , Porter J 1 , O’Connor SP 1 ,
Czeisler CA 1,2 , Shea SA 1,2
1
Department of Medicine, Brigham and Women’s Hospital, Boston,
MA, USA, 2 Division of Sleep Medicine, Harvard Medical School,
Boston, MA, USA
Introduction: Aging is generally associated with reduced sleep and
increased obesity. Sleep deficiency (insufficient sleep quantity or quality)
and circadian misalignment impair glucose metabolism in young
adults. We tested whether a history of ~ 17 days of circadian disruption
combined with sleep deficiency lead to metabolic disturbances in older
adults, predisposing them to greater risk of obesity and diabetes.
Methods: 11 healthy, non-obese, older adults (6F, mean age 59 y) completed
a 39-day study with three conditions: (1) ‘Sleep Replete’ (>2
weeks of >10 h/day time in bed [TIB]/day); (2) ‘Circadian Disruption
and Sleep Deficiency’ (achieved via recurring 28 h sleep/wake cycles
for ~2.5-weeks with 6.5h TIB/28h cycle; ≡5.6h TIB/24h); (3) ‘Recovery
Sleep’ (1 week of 10h TIB/24h). Metabolic assessments were
made across conditions at similar circadian phases following standardized
breakfasts (58-60% CHO). Results were compared to data from 12
healthy, non-obese, younger adults (6F, mean age 23 y).
Results: In the older group, prolonged ‘Circadian Disruption and Sleep
Deficiency’ significantly increased post-prandial plasma glucose by
16.3% (AUC across 90 min; p=0.04). This effect was likely caused by
an inadequate pancreatic beta cell response because post-prandial plasma
insulin decreased by 23.7% (AUC across 90 min; p=0.02). Glucose
and insulin responses to meals returned to baseline ‘Sleep Replete’ levels
after ‘Recovery Sleep’. These results in elderly subjects were statistically
indistinguishable from those in the young adults; both younger and
older adults exhibited similar, reversible metabolic disturbances.
Conclusion: Circadian disruption combined with sleep deficiency for
2.5 weeks caused a notable increase in the glucose response to a meal
due to inadequate insulin secretion. The metabolic disturbances were reversible
in the short-term but may underlie the elevated risk of diabetes
in conditions of chronic circadian disruption or sleep deficiency.
Support (If Any): This work was supported by a grant from the National
Institute on Aging (P01 AG009975) and was conducted in the
General Clinical Research Center supported by the National Center for
Research Resource (NCRR M01 RR02635) and the Harvard Clinical
and Translational Science Center (1 UL1 RR025758-01). The content is
solely the responsibility of the authors and does not necessarily represent
the official views of the NCRR, NIA, or NIH.
0474
LABORATORY VALIDATION OF AN IN-HOME METHOD
FOR ASSESSING CIRCADIAN PHASE USING THE DIM
LIGHT MELATONIN ONSET (DLMO)
Pullman R 1 , Roepke SE 1 , Duffy JF 1,2
1
Division of Sleep Medicine, Brigham and Women’s Hospital, Boston,
MA, USA, 2 Division of Sleep Medicine, Harvard Medical School,
Boston, MA, USA
Introduction: Methods for assessing circadian rhythm timing typically
require lengthy procedures in highly controlled laboratory conditions,
and thus are impractical for use in patients. This study addressed whether
an accurate circadian phase assessment can be obtained from saliva
samples collected by patients in their home.
Methods: Twenty-four individuals reporting sleep timing difficulties
were recruited for the study. For 1-2 weeks, each wore an activity monitor
and recorded their sleep-wake times. On the last day, participants
were instructed to remain in dim light at home beginning 7h before their
usual bedtime and to collect hourly saliva samples until 1h after their
usual bedtime (8 samples). Participants spent 9h on the following evening
in a laboratory room with controlled dim (