Risk Factors for Vitamin D Deficiency in Children With Osteogenesis Imperfecta

Background: The purpose of this study was to evaluate the prevalence of vitamin D deficiency and possible risk factors influencing the vitamin D serum levels in patients with osteogenesis imperfecta (OI). Methods: Charts of all children with OI seen at Shriners Hospitals for Children in Houston, TX, between November 2008 and June 2011 were reviewed for daily milk and soda consumption, multivitamin and vitamin D supplementation, time spent outside, use of sunscreen, amount of screen time, ambulatory status, height, weight, body mass index (BMI), serum 25 hydroxyvitamin D (25OHD), parathyroid hormone levels, and history of bisphosphonate treatment. Results: Of the 80 children with OI, charts of 44 children (26 female) had documentation of the variables of interest. Mean level of 25OHD was 23 ng/mL (+/- 11) (range, 7 to 58) and 35 (79.5%) patients had insufficient or deficient levels. Significant correlations with low vitamin D levels were found for older age (P<0.001), African American descent (P=0.01), BMI (P<0.001), BMI percentile (P=0.30), consumption of soda (P=0.009), and pamidronate therapy (P=0.004). Evaluated together, the studied variables accounted for a large proportion of the variability of 25OHD levels in patients with OI (P=0.004). Conclusions: To optimize bone health in children with OI, health care providers need to be aware of patients' risk factors for low vitamin D levels and educate families on the modifiable risk factors of milk and soda consumption, obesity, and vitamin D supplementation. Future research is needed to address the relationship between fractures and vitamin D levels in patients with OI and on the cause and effect relationship between bisphosphonate therapy and vitamin D.