Background: Impaired growth and delayed puberty are common in pediatric Crohn's disease (CD). Bone age (BA) is important for interpretation of statural growth. Our aims were to 1) determine the distribution of BA-Z scores; 2) identify clinical factors associated with BA-Z scores; and 3) compare anthropometric Z scores based on chronological age (CA) (CA-Z) versus BA-Z in pediatric CD.
Methods: CD patients ≤CA 15 in females and 17 years in males were enrolled in a cross-sectional study. BA was determined with left hand/ wrist x-ray. In all, 49 patients (65% male; 84% Caucasian; mean CA 13 years) examined between January 2007 and July 2009 qualified for the study.
Results: Mean BA-Z score was −1.40 ± 1.50 (standard deviation). 41% had BA-Z score < −2.0. Mean BA-Z scores were lower in females (P = 0.02), Caucasians (P = 0.006), Tanner stage 1-3 children (P = 0.004), and patients with colonic disease (P = 0.0006), past corticosteroid exposure (P = 0.01), current azathioprine/6-mercaptopurine treatment (P = 0.003), or lower height (P = 0.006), weight (P < 0.001), or body mass index (BMI) (P = 0.01) CA-Z scores. Mean height, weight, and BMI BA-Z scores were 0.73 units (P < 0.0001), 0.51 units (P < 0.0001), and 0.23 units (P < 0.0001) greater than mean height, weight, and BMI CA-Z scores.
Conclusions: Low BA occurs frequently in CD. Determination of BA should become the standard of care in pediatric CD patients, allowing clinically meaningful interpretation of growth in the context of skeletal maturation, leading to improved treatment recommendations, as growth is a dynamic marker of disease status. Prospective longitudinal studies are required to clarify determinants of BA and patterns of BA advancement in CD.