25(OH)D	Calcifediol, 25-hydroxycholecalciferol monohydrate, prohormone of the vitamin D system
CI	Confidence interval, the lower and upper limits of significance
IBS	Irritable bowel syndrome, a common gastrointestinal condition affecting 7–12% of the general population [1], characterized by fluctuating severity of symptoms, including abdominal discomfort, pain, bloating, and alternating bowel habits
IBS-QoL	Irritable bowel syndrome quality of life [36]
IBS-SSS	Irritable Bowel Severity Scoring System [35]
IU	International unit
MD	Mean difference
N/A	Not available
p	Probability
PRISMA	Preferred Reporting Items for Systematic Reviews and Meta-Analyses [33]
RCT	Randomized controlled trial
SD	Standard deviation
WOS	Web of Science