Abstract Details

Title Time-of-day Pattern of Stroke Onset in Women: Interim Analysis Linking Menopausal Status and Autoimmune Comorbidity to Circadian Patterns

Topic Cerebrovascular Disease and Interventional Neurology

Presentation(s) P10 - Poster Session 10 (8:00 AM-9:00 AM)

Poster/Presentation
Number 4-003

Objective To characterize timing of ischemic stroke and TIA in women and explore associations with initial severity, autoimmune status, and menopausal proxy metrics.

Background

Circadian variation in stroke onset is well established, with ischemic events most frequent in the morning. Most prior studies included predominantly men or mixed cohorts, limiting insight into sex-specific mechanisms. Hormonal transitions such as menopause, and autoimmune conditions that disproportionately affect women, may alter circadian regulation, vascular reactivity, and hemostasis, influencing stroke timing and severity. Identifying high-risk windows in women could guide tailored prevention strategies

Design/Methods Two reviewer-curated datasets (2019–2025) were merged and limited to women. Diagnoses were identified via ICD-10 codes (I63.* ischemic stroke; G45.* TIA). Time of day was categorized into four 6-hour bins (00:00–05:59; 06:00–11:59; 12:00–17:59; 18:00–23:59). NIHSS at arrival defined initial severity. Autoimmune positivity was defined as a documented autoimmune condition or positive laboratory tests around the time of stroke. Menopausal status was proxied by age ≥50 years.

Results Among 435 encounters, 227 were women; 79 had ischemic stroke or TIA. Peak 6-hour window was 12:00–17:59 (n=32). NIHSS mean was 5.3, median 2.0 (n=210). Autoimmune positivity occurred in 30/227 (13.2%) overall, 12/79 (15.2%) with stroke/TIA. Using the menopause proxy, 188/227 (82.8%) were ≥50 years; 73/188 (38.8%) had stroke/TIA. Women <50 years (n=6) had events across all time bins without a dominant peak; median NIHSS 2.5 (IQR 2.0–7.5). Women ≥50 years (n=73) had 42.5% presenting 12:00–17:59; median NIHSS 4.0 (IQR 2.0–10.0).

Conclusions Stroke/TIA in women, particularly ≥50, tends to cluster in the afternoon, with older women showing modestly higher NIHSS. Autoimmune positivity was 13–15%. Findings suggest circadian, hormonal, and immune modulation of stroke onset. The study is ongoing; this interim analysis precedes cohort expansion (2019–2025)

Authors/Disclosures
Shayan Sadegh PRESENTER	Mr. Sadegh has nothing to disclose.
Parisa Heidari, MD	Dr. Heidari has nothing to disclose.

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