Vitamin D Status and Bone Mineral Density in Children with Inflammatory Bowel Disease Compared to Those with Functional Abdominal Pain

Abstract

Low vitamin D has been implicated in reduced bone mineral density (BMD) in children with inflammatory bowel disease (IBD). Our study aimed to evaluate differences in serum 25-hydroxyvitamin D (25[OH]D) and total body less head (TBLH) BMD z-scores in children with Crohn's disease (CD), ulcerative colitis (UC), and those with abdominal pain-related functional gastrointestinal disorder (AP-FGID) as the control group. We also examined the correlation between serum 25(OH)D and TBLH BMD z-score, and factors that affect each of these parameters. A total of 105 children were included and divided into 3 groups: AP-FGID (n = 45), CD (n = 43), and UC (n = 17). Among the 3 study groups, TBLH BMD z-scores were found to be significantly different (0.5 ± 0.8 in CD vs. 0.1 ± 0.8 in UC vs. -0.1 ± 1.1 in FGID; P = 0.037), despite similar levels of serum 25(OH)D. Within each study group, correlation between serum 25(OH)D and TBLH BMD z-score was not observed. Factors found to affect the TBLH BMD z-score were sex (P = 0.018), age (P = 0.005) and serum hemoglobin (P = 0.041), while factors influencing serum 25(OH)D were sex (P = 0.018), CD with reference to AP-FGID (P = 0.020), and serum phosphorus (P = 0.018). Based on our results, vitamin D is a relatively small contributor to bone loss in pediatric IBD and clinicians should consider female sex, older age, and low hemoglobin as risk factors for low BMD in children with IBD.

Keywords: Asian; Bone Mineral Density; Children; Inflammatory Bowel Disease; Vitamin D.

Fig. 1

Correlation between serum 25(OH)D and TBLH BMD z-score in the 3 study groups. There was no significant correlation in the AP-FGID group (r = 0.151; P = 0.323), CD group (r = 0.249; P = 0.132), or the UC group (r = −0.032, P = 0.906). 25(OH)D = 25-hydroxyvitamin D, TBLH = total body less head, BMD = bone mineral density, AP-FGID = abdominal pain-related functional gastrointestinal disorder, CD = Crohn's disease, UC = ulcerative colitis.