A study conducted in southern Thailand has found a higher incidence of non-recurrent ischaemic stroke among Muslims during the Ramadan period (when Muslims observe a ‘fasting window’ from sunrise to sunset) compared with the rest of the year.
The retrospective 5-year observational study compared the incidence of ischaemic stroke between Muslims and non‑Muslims living in the same geographical region in southern Thailand who shared similar environmental exposures. It included 1,304 patients (Muslims, n=898; non-Muslims, n=406; average age, 63.0 and 64.5 years, respectively; male, 71.2 and 70.2 percent, respectively) admitted to the Stroke Unit at Yala Regional Hospital between 5 December 2013 and 10 September 2018 (Hijri years [AH] 1435–1439) who experienced their first ischaemic stroke confirmed through clinical assessment and brain CT. [Singapore Med J 2026;67:170-175]
The study was divided into three periods according to AH months: baseline (months 1–4), pre‑Ramadan (months 5–8) and Ramadan (months 9–12). This broader classification (rather than limiting assessments to 1 month before and after Ramadan fasting) was intended to minimize noise from monthly seasonal environmental variations influencing stroke incidence. Poisson regression was performed to explore the association between the time periods and incidence rates (IR) of ischaemic stroke per 100,000 population.
Across all three periods combined, Muslims had a higher mean IR than non-Muslims (10.7 vs 4.9; p=0.016). This difference was likely driven by the significantly higher incidence among Muslims during Ramadan (mean IR, 13.5 vs 5.4; p=0.032). No significant differences were observed between the groups at baseline or during the pre-Ramadan periods.
Among Muslims, the IR ratio (IRR) during Ramadan was higher compared with baseline (1.07 vs 1.00; p=0.049), while no significant change was seen in the pre-Ramadan period (0.97; p=0.576). Among non-Muslims, IRRs remained stable across all periods. These findings indicate a likelihood of Ramadan-related behaviour or physiological changes influencing stroke risk among Muslims, but not the non-Muslim population in the same environment.
Smoking, a well-established strong risk factor for stroke, was found to be more prevalent among Muslims than non-Muslims in this cohort (43.6 vs 30.9 percent; p=0.004). The authors also noted a tendency for chain smoking after sunset during the fasting month, as well as excessive smoking after the Ramadan fasting month – behaviours that may contribute to the observed increase in stroke incidence. These findings are consistent with those of a similar long-term study in 2012–2016 among Bedouin Arabs, as well as a Jordanian study documenting excessive smoking following fasting‑related abstinence, indicating a need for further research on the effects of smoking behaviour during Ramadan on health and stroke risk. [J Am Heart Assoc 2018;7:e008018; Clin Pract Epidemiol Ment Health 2021;17:114-120]
In addition to smoking, the authors highlighted several factors requiring further investigation: poorer adherence to medications during Ramadan; detrimental effects of fasting on plasma glucose levels and volume depletion in individuals with diabetes; and their combined influence on stroke risk. Other possible factors, such as changes in body weight, body composition, metabolic parameters, haemodynamics and inflammatory markers before and after Ramadan, which have been extensively studied, may have also contributed to the increased incidence.
While the current study demonstrated an association between Ramadan fasting and increased stroke incidence, the authors noted that it does not establish causality or elucidate the underlying pathogenesis. They urged healthcare systems to examine the pathogenic mechanisms and factors contributing to the increased incidence of ischaemic stroke during Ramadan to mitigate the risk of this morbidity.