Demographic Profiles, Clinical Characteristics, and Meteorological Context of Heat-Related Illnesses among Hajj Pilgrims in 2023.

Objective: To describe the demographic profiles, clinical characteristics, and meteorological context of heat-related illnesses among Hajj pilgrims in 2023. Methods: A retrospective cross-sectional study was conducted using data from 1,129 pilgrims diagnosed with HRIs across healthcare facilities in Mecca, Mina, and Arafat. Demographic and clinical data were extracted from the Hajj Health Information System, while temperature, humidity, wind speed, and rainfall records were obtained from the National Center for Meteorology. Results: Heat exhaustion (48.2%) and heatstroke (37.4%) were the most common diagnoses, with 24.9% of the cases requiring hospitalization. Males represented 55.4% of cases and accounted for 51.2% of hospitalizations. Pilgrims aged 55-74 years comprised 64.2% of severe cases, while Egyptians were disproportionately affected (32.2% of cases). Meteorological data revealed high temperatures reaching 44°C during the Day of Arafah, accompanied by low humidity (14%) and moderate wind speeds of approximately 7 km/h, with no rainfall (0 mm). Conclusion: The findings underscore the need for targeted interventions, including heat-adaptive rituals, real-time environmental monitoring, and age-specific cooling strategies, to protect pilgrims as climate change intensifies. This study provides a benchmark for future research on mass gatherings in warming environments.