OBJECTIVETo observe the relationship between vitamin D status and seasons, disease activity, disease location, growth and steroid treatment in children with Crohn's disease (CD). To search for the risk factors of vitamin D deficiency in CD children. To discuss the role of vitamin D in the pathogenesis and treatments of CD.

METHODSixty CD children (63.3% male) and 121 sex- and age-matched healthy subjects were enrolled. Data including growth, clinical characteristics, time for vitamin D blood test, erythrocyte sedimentation rate, C reactive protein, serum 25(OH)D concentration and steroid treatments were collected. The relationship between vitamin D status and disease activity, disease location, growth and steroid treatments in children with CD were analized.

RESULTThe serum concentration of 25(OH)D was 57.2(22.3-246.0) nmol/L, which was significantly lower than that of controls (67.3 (57.3-78.4) nmol/L) (Z=-5.009, P=0.000). Hypovitaminosis D was most prevalent during the winter and spring (November to April, 46.8(31.8-83.4) nmol/L) rather than summer and autumn (May to October, 63.3(22.3-246.0) nmol/L, Z=-1.994, P=0.046). Univariate logistic regression demonstrated that factors increasing the risk of vitamin D deficiency in Crohn's disease were: age over 10 years (OR=4.571, 95% CI: 1.452-14.389), small intestine involved diseases (OR=5.211, 95% CI: 1.278-21.237), high C reactive protein levels (≥8 mg/L) (OR=4.500, 95% CI: 1.094-18.503) and steroid therapy (OR=4.297, 95% CI: 1.413-13.068). Among those risk factors, all but age were determined to be risks of vitamin D deficiency by further multivariate logistic regression. There was no significant correlation between vitamin D deficiency and gender, disease duration, stricture, penetration, perianal disease (fistula, ulcer or abscess), white blood cell counts, hemoglobin, platelet counts, erythrocyte sedimentation rate, serum albumin levels, pediatric Crohn's disease activity index and nutrition therapy (P>0.05).

CONCLUSIONHypovitaminosis D was prevalent in children with CD. Serum concentration of vitamin D was associated with season. Steroid treatment, small intestine involved disease and high C reactive protein (more than 8 mg/L) are risk factors of vitamin D deficiency in CD children.