Abstract Body: Introduction: Prior research has reported sex differences in sleep and cardiovascular health. Most studies focused on disturbed sleep, sleep duration, and night-to-night sleep variability; however, sex differences in circadian misalignment and its impact on obesity-related cardiovascular outcomes remain elusive.
Hypothesis: We hypothesize that male adolescents will show greater circadian misalignment and that its impact on cardiovascular outcomes will vary by sex.
Methods: We analyzed 303 adolescents from the Penn State Child Cohort (median 16y; 144 females; 21% racial/ethnic minority) who had at least 5 nights of actigraphy (ACT), in-lab dual-energy X-ray absorptiometry (DEXA) scan, and polysomnography (PSG) data. ACT-measured sleep midpoint (SM) was calculated as the intra-individual average of the 7-night midpoint (zeroed to midnight) of the sleep period. ACT-measured sleep irregularity (SI) was calculated as the intra-individual standard deviation of the 7-night sleep midpoint. Social jetlag (SJL) was calculated as the absolute difference between weekends and weekdays SM. DEXA-measured visceral adipose tissue (VAT) was the primary predictor. Systolic (SBP) and diastolic (DBP) blood pressure, measured three times in the seated position, were the primary outcomes. Multivariable-adjusted means of SM, SI, and SJL for males and females were calculated. Thereafter, multivariable linear regression models stratified by sex tested the main effects and interaction effects of SM, SI, and SJL on VAT with SBP/DBP levels, while adjusting for race/ethnicity, age, ACT-sleep duration, ACT-sleep variability and PSG-apnea/hypopnea index.
Results: Male adolescents had a SM 22 minutes later (p=0.010) than females. No significant sex differences in SI and SJL were observed. In males, a significant positive main effect was found between SM and SBP (p=0.030). In females, significant positive interactions were found between SI and VAT on SBP and DBP (p-interactions=0.002 and 0.030, respectively) and between SJL and VAT on SBP (p-interaction=0.002).
Conclusions: The role of circadian misalignment in cardiovascular health does vary by sex. Females appear more vulnerable to its impact on the association between visceral adiposity and elevated blood pressure. Future studies should examine the underlying pathways, whether circadian, biological or behavioral, that may explain the observed sex differences.
Support: AHA (23PRE1011962), NIH (R01HL136587, R01MH136472, UL1TR000127)