Comparison of Vitamin D, B12, and Folic Acid Levels According to Attack Frequency in Familial Mediterranean Fever Cases.

Objectives: Familial Mediterranean fever (FMF) is an autoinflammatory disease more commonly observed in the Eastern Mediterranean region. Studies have shown that inflammatory processes may decrease vitamin D, vitamin B12 and folate levels, but there is no clear data on the effect of attack frequency on these levels. Our study aimed to evaluate the effect of FMF attack frequency on vitamin levels.

Methods: FMF patients aged between 4-18 years were considered as the study group, while healthy children who had vitamin levels during the same period were considered as the control group. The study group was further subgrouped according to the number of attacks. Those experiencing 2 or fewer attacks per year are classified as the attack group, while those experiencing 6 or more attacks per year are classified as the frequent attack group.

Results: A total of 494 subjects were included. The study group was composed of 333 FMF patients, 108 of them in the attack group and 225 in the frequent attack group. Control group included 161 children. The median and interquartile range (IQR: P25-75) in the frequent attack, attack, and control groups for 25(OH)D levels were 14.3 (9.57-18.9), 14.85 (10.12-21.77), and 14.95 (9.92-20.12) ng/ml, for B12 levels were 320 (238-415), 328 (250.25-439.25), and 373 (273.75-519.25) pg/ml, and for folate levels were 6 (5.13-8.12), 6.8 (5.36-8.9), and 7 (5.3-9.9) ng/ml, respectively. There is no significant difference between groups for 25(OH)D and folate (p=0.436 and p=0.25, respectively). Vitamin B12 levels are significantly lower in study group (p=0.001) but there is no difference according to attack frequency (p=0.92).

Conclusion: There is no effect of attack frequency on 25(OH)D, vitamin B12 and folate levels. The fact that vitamin B12 levels are within normal limits in patients with FMF may be explained by the adequate dietary habits of these patients.