Decreased vitamin D levels in children with familial Mediterranean fever

ObjectivesTo determine the frequency of vitamin D deficiency in children with familial Mediterranean fever (FMF) and to investigate the factors associated with low vitamin D status. Design and methodsForty-four patients with FMF and 39 age- and sex-matched healthy controls were enrolled in this study. Demographic data, FMF symptoms, disease duration, time to delay for diagnosis, duration of follow-up, disease severity score, MEFV gene mutation, cumulative colchicine dose, compliance to treatment and serum C-reactive protein levels were recorded for each patient. Serum 25-hydroxyvitamin D levels were measured by an original commercial kit based on chemiluminescent microparticle immunoassay (CMIA). ResultsThe serum 25-hydroxyvitamin D levels were significantly lower in FMF patients than the healthy controls (12.93.6 and 16.3 +/- 5.5ng/mL, respectively, P=0.001). Vitamin D levels were similar in patients homozygous for M694V and other genotypes (11.8 +/- 3.7 and 13.2 +/- 3.6ng/mL, respectively, P=0.21). Stepwise multiple linear regression analysis confirmed that the cumulative colchicine dose was the strongest independent variable correlating with vitamin D levels (r(2)=0.194, P=0.001). ConclusionOur results suggest that serum 25-hydroxyvitamin D levels are decreased in children with FMF. Cumulative colchicine dose appears to negatively affect vitamin D levels. The role of colchicine on vitamin D metabolism needs to be elicited.