Ischemic stroke remains a leading cause of mortality and long-term disability worldwide, with established risk factors including hypertension, diabetes mellitus, smoking, and dyslipidemia.¹ Annual Ramadan fasting is observed in millions of Muslims globally and has been associated with various metabolic and cardiovascular effects; however, its precise relationship with acute neurovascular risk has historically remained unclear.^2-4 To address this gap, a new five-year retrospective study published in the Singapore Medical Journal evaluated stroke patterns among populations in southern Thailand, revealing a significant increase in first-time ischemic strokes among Muslims during the Ramadan season.⁵

This holy month involves a strict abstinence from food, fluids, and smoking during daylight hours, resulting in substantial changes in dietary habits, sleep patterns, metabolism, immune function, and daily routines.⁵ Because prior literature examining fasting-induced stroke risk yielded inconsistent findings due to regional and cultural variations, researchers analyzed a localized cohort of 1,304 patients admitted to the Stroke Unit at Yala Regional Hospital, Thailand, between December 5, 2013, and September 10, 2018, spanning the Hijri years 1435 to 1439.⁵ After excluding stroke mimics using radiologist-certified brain computed tomography, the final cohort tracking first-ever ischemic strokes comprised 898 Muslim and 406 non-Muslim patients who shared similar environmental exposures.⁵ To minimize the confounding influence of seasonal variations, each Hijri year was divided into three distinct four-month blocks: a baseline period (months 1-4), a pre-Ramadan period (months 5-8), and Ramadan (months 9-12).⁵

Baseline demographic and traditional vascular risk factors, such as hypertension, diabetes mellitus, atrial fibrillation, age, and sex distribution, were broadly comparable between Muslims and non-Muslims.⁵ However, smoking prevalence was significantly higher among Muslims than non-Muslims (43.6% vs. 30.9%; p=0.004).⁵ Overall, Muslims demonstrated a significantly higher mean incidence of ischemic stroke than non-Muslims (10.7 vs. 4.9 per 100,000 population; p=0.016).⁵ This difference appeared to be primarily driven by the Ramadan period, during which stroke incidence among Muslims reached 13.5 per 100,000 population vs. 5.4 per 100,000 among non-Muslims (p=0.032).⁵ No significant differences were observed between the groups during baseline or pre-Ramadan periods.⁵

Among Muslims, the incidence of ischemic stroke during the Ramadan period was 7% higher than during the baseline period (Incidence rate ratio [IRR]=1.07; 95% CI: 1.00-1.15; p=0.049), whereas no significant change was observed among non-Muslims.⁵ Notably, while the study demonstrated an association between Ramadan and ischemic stroke incidence, the underlying mechanisms remain unclear, and causality cannot be established given the limited data on behavioral factors that may influence stroke risk during and after Ramadan.⁵

Stroke severity at presentation, as measured by the National Institutes of Health Stroke Scale (NIHSS), was similar between Muslims and non-Muslims (median NIHSS=5 for both groups; p=0.375).⁵ Among Muslims, however, stroke severity varied significantly across study periods, with median NIHSS scores of 6, 5, and 5 during the baseline, pre-Ramadan, and Ramadan periods, respectively (p=0.017).⁵

Ramadan fasting has been associated with changes in body weight, body composition, metabolic parameters, hemodynamics, and inflammatory markers.⁵ While reductions in inflammatory cytokines have been reported, potential adverse effects such as sleep deprivation, altered circadian rhythms, reduced physical activity, and volume depletion have also been observed.⁵ Inadequate fluid intake over Ramadan may contribute to dehydration, a recognized risk factor for acute stroke, while individuals with diabetes may experience greater fluctuations in plasma glucose levels during fasting.⁵ These changes may explain the higher incidence of ischemic stroke during the Ramadan period.⁵

In conclusion, this long-term observational study demonstrated a higher incidence of first ischemic stroke among Muslims during the Ramadan period compared with non-Muslims living in the same region, highlighting the need for greater attention to the underlying pathophysiological and causal factors that may contribute to this increase.⁵ Improved understanding of these mechanisms could help inform preventive strategies and reduce the burden of stroke during Ramadan.⁵