Abstract Body (Do not enter title and authors here): Aim: To determine whether vitamin D (VD) status moderates the association between insufficient sleep duration (ISD) and hypertension (HTN) and whether these associations differ by sex among a diverse sample of U.S. adults.

Methods: A cross-sectional analysis of 2021–2023 NHANES data included adults (18–80 years). Demographics and ISD were self-reported, while vitamin D status from biosamples was analyzed as continuous (nmol/L) and categorical (Sufficient, Insufficient, Deficient). Hypertension (HTN) was defined as SBP ≥130 mmHg or DBP ≥80 mmHg. Weighted multivariable logistic regression models estimated overall and subgroup (age-, sex-, and race-specific) associations, adjusted for age, sex, race/ethnicity, smoking, alcohol use, and BMI. Each subgroup model adjusted for the remaining covariates.

Results: This study included 6039 adults (mean age: 47.8 (SE=0.6); mean BMI: 29.5 kg/m² (SE=0.3); 51.3% female, 60.2% non-Hispanic White, 16.8% Hispanic/Latino, 10.8% non-Hispanic Black, and 12.2% other or multiple races). Nearly 24.4% of the sample had HTN, 20.5% had ISD, 20.2% were deficient in Vit D, and 30.2% had insufficient Vit D levels. Additionally, 61% of participants were either married or living with a partner, 36.6% smoked at least 100 cigarettes in their lifetime, 8.8% consumed at least 1 alcoholic beverage every day in the last 12 months, and 34.5% had a college degree or higher. After adjustment for demographics and health behaviors, non-Hispanic Asian adults with ISD vs. without ISD were almost twice as likely to have HTN [aOR=1.98; 95% CI: 0.66, 5.93; p=0.20], followed by mixed-race adults [aOR=1.10; 95% CI: 0.56,2.15; p=0.77], and non-Hispanic Black adult [aOR=1.05; 95% CI: 0.63, 1.74; p=0.83]. Young adults in the 18-to-39-year age group had the strongest association between ISD and HTN [aOR=1.06; 95% CI: 0.65, 1.74; p=0.80] compared to those in older age groups. There was a borderline interaction between ISD and Vit D in relation to HTN (p=0.058).

Conclusion: Though non-significant, this nationally representative study suggests potential age/race-specific ISD and HTN Associations in adults, with vitamin D deficiency possibly influencing this relationship. Longitudinal studies with larger samples are needed to clarify ISD and HTN Causality.