Circadian Disruption And Cardiovascular Risk In Young Adults With Hypertension

This study is designed to investigate the relationship between circadian organization, sleep-wake patterns, and cardiovascular characteristics in young adults with established essential arterial hypertension. The study is based on the hypothesis that circadian disruption may be associated with an adverse cardiovascular phenotype, particularly alterations in the 24-hour blood pressure profile and early markers of cardiovascular remodeling.

Circadian organization will be assessed using prolonged ambulatory wrist actigraphy. A predefined research index will integrate five complementary indicators of circadian rhythmicity and sleep-wake regularity. The index is intended to provide an operational and reproducible classification of the degree of circadian disruption within the study population rather than to establish a clinical diagnosis of a circadian rhythm sleep-wake disorder.

Cardiovascular assessment will include ambulatory blood pressure monitoring, echocardiographic assessment of cardiac structure and function, heart-rate variability, and selected metabolic and inflammatory biomarkers. Psychological and sleep-related factors will also be assessed in order to explore the potential contribution of perceived stress and insomnia symptoms to the relationship between circadian organization and cardiovascular characteristics.

The primary analytical approach will compare participants classified as having a positive Circadian Disruption Index with those classified as negative. Multivariable statistical models will subsequently be used to determine whether the observed association between circadian disruption and cardiovascular parameters persists after adjustment for relevant demographic, anthropometric, hypertension-related, treatment-related, and sleep-related factors.

An additional exploratory objective is to evaluate whether a combination of cardiovascular, metabolic, behavioral, and psychological characteristics can identify participants with a higher probability of circadian disruption. This exploratory analysis may contribute to the development of a preliminary cardiovascular-circadian risk metric that could subsequently be evaluated and validated in independent cohorts.

The study is observational and does not assign participants to a therapeutic intervention. The research classification of circadian disruption should not be interpreted as a diagnosis of a circadian rhythm sleep-wake disorder, and the findings will be interpreted in the context of the overall clinical characteristics of the participants.

Inclusion criteria

• Adults aged 18 to 45 years.
• Established diagnosis of essential arterial hypertension.
• Stable antihypertensive treatment for at least 4 weeks before enrollment, when pharmacological treatment is prescribed.
• Ability and willingness to undergo 14 consecutive days of wrist actigraphy using the CamNtech MotionWatch 8.
• Ability and willingness to undergo 24-hour ambulatory blood pressure monitoring.
• Ability to provide written informed consent.

Exclusion criteria

• Shift work or night-duty work.
• Known secondary hypertension.
• Previously diagnosed circadian rhythm sleep-wake disorder.
• Known obstructive sleep apnea or other clinically significant sleep-related breathing disorder.
• Known clinically significant cardiovascular disease other than uncomplicated essential arterial hypertension.
• Diabetes mellitus.
• Chronic kidney disease with clinically significant renal impairment.
• Active thyroid disease or other clinically significant endocrine disorder that may affect blood pressure or circadian rhythm.
• Current treatment with medications known to substantially alter sleep-wake rhythm or circadian timing.
• Regular use of hypnotic or sedative medication that could substantially affect actigraphic sleep assessment.
• Pregnancy.
• Inability to comply with study procedures or insufficient actigraphy/ABPM recording quality.
• Any acute illness or unstable medical condition that, in the investigator's opinion, could substantially influence the study outcomes.