0278 Sex Differences in Circadian Timing and Alignment: Associations with Actigraphic and Self Reported Sleep. (12th April 2019) - McCullough, Lindsay M
Abstract: Introduction: Sex differences have been demonstrated in circadian timing and alignment. The goal of this study is to examine sex differences in the relationship between circadian timing and alignment with sleep timing and quality. Methods: In this secondary analysis, healthy adults with habitual sleep duration ≥ 6.5 hours completed 7 days of wrist actigraphy. Circadian timing, measured by dim light melatonin onset, was measured in the clinical research unit. Circadian alignment was calculated as the duration between dim light melatonin onset (DLMO) and average sleep onset time in the prior week (phase angle). Participants also completed measures of depressive symptoms and subjective sleep quality. Data were analyzed using bivariate correlations conducted separately for men and women. Results: Participants included 36 men and 61 women. Mean age 26.4 years (SD= 7.1 years). Average sleep duration was 436.2 min (SD= 55.1 min). There were no significant sex differences in sleep or circadian variables; however, there was a trend for earlier DLMO in women compared to men, (22.41 vs. 22.95, p= 0.08). For both men and women, later DLMO was associated with shorter phase alignment (r=-0.42, p=<.001), later sleep onset time (r=0.77, p=<.001), lower sleep efficiency (r=-0.37, p<.001), and higher depressive symptoms (r=0.27, p=<0.05). Among women, later DLMO was also associated with shorter sleep duration (r=-0.28, p<.05). Shorter phase alignment was associated with earlier sleep onset time among women (r=0.43, p<.01) and among men was associated with longer sleep duration (r=-0.43, p<.01). Circadian timing and alignment were not associated with subjective sleep quality in men or women. Conclusion: These data demonstrate sex differences in the relationship between circadian timing and alignment with objective measures of sleep. Support (If Any): N/A