Objectives: The aim of the study was to examine the association of corticosteroid exposure and other skeletal risk factors with bone mineral density (BMD) and fractures following pediatric liver transplantation (LT) at a large single center.
Patients and Methods: Lumbar spine BMD, measured using dual-energy x-ray absorptiometry (DXA), was corrected for bone age in 52 ambulatory children ages 4 to 18 years, at least 1 year post-LT. Potential risk factors for skeletal health such as corticosteroid exposure, dietary and lifestyle factors, and growth and fracture occurrence, were related to BMD using univariate and multivariate regression analyses.
Results: The prevalence of low BMD (z score <−2) and post-LT fractures was 3 of 52 (5.8%) and 11 of 52 (21%), respectively. Univariate analysis revealed age >10 years at LT and body mass index (BMI) <85th percentile at time of DXA were significantly associated with BMD (both P = 0.02). BMD did not correlate with corticosteroid dosage in the first year post-LT, the year before DXA or cumulative lifetime exposure. A cholestatic primary LT indication, acute rejection episodes, and fractures post-LT were not associated with BMD. Extracurricular physical activity, vitamin D, and calcium intake were not associated with BMD or fractures. Multivariate linear regression revealed increased time post-LT (P = 0.04) and higher BMI z score at time of DXA (P = 0.02) as the strongest independent variables associated with greater BMD.
Conclusions: Neither corticosteroid exposure nor a cholestatic primary indication for LT influenced BMD, which was largely normal in this ambulatory group. Children and adolescents undergoing LT after the age of 10 years and those with low BMI post-LT may be at greatest risk of poor skeletal health later in life, and thus a potential target patient population to benefit from preventive interventions.
*SickKids Transplant Centre, the Hospital for Sick Children, University of Toronto
†Osteoporosis Research Program, Women's College Ambulatory Care Center
‡Bloorview Research Institute, Bloorview Kids Rehab
§Paediatric Outcomes Research Team, the Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
Address correspondence and reprint requests to Vicky L. Ng, MD, FRCPC, Division of Gastroenterology and Nutrition, The Hospital for Sick Children; 555 University Ave, Toronto, ON, Canada (e-mail: firstname.lastname@example.org).
Received 5 January, 2011
Accepted 12 May, 2011
The study was funded by a SEED grant from the Hospital for Sick Children, Toronto, Ontario, Canada. S.N. was supported in part by the Eric Burnard Fellowship, Royal Australasian College of Physicians.
This study was presented in part at the American Transplant Congress 2005 Seattle (Am J Transplant 2005;5(suppl 11):337), and at the International Pediatric Transplantation Association Fellow's Symposium, Hannover, Germany 2010.
The authors report no conflicts of interest.