Current Treatment Recommendations for Correcting Vitamin D Deficiency in Pediatric Patients with Cystic Fibrosis Are Inadequate

Objectives To determine the prevalence of vitamin D deficiency (25-hydroxy vitamin D [25-OHD] levels in plasma < 30 ng/mL) in pediatric patients with cystic fibrosis (CF), elucidate contributing factors for vitamin D deficiency, and determine the efficacy of ergocalciferol repletion strategies. Study design Retrospective chart review of 262 pediatric patients from January 2003 to December 2006 with linear and logistic regression analyses. Results Vitamin D deficiency prevalence declined in the years studied from 86.5% to 46.2%. Patients > 12 years old were more likely to have deficiency than patients < 5 years old (odds ratio [OR], 3.44; 95% CI, 1.73-6.84). Levels obtained in spring and summer were less likely to be deficient compared with those obatined in fall (OR, 0.24; 95% CI, 0.10-0.61; and OR, 0.25; 95% CI. 0.11-0.61; respectively). Success of treatment with 50 000 IU of ergocalciferol once, twice, or 3 times weekly was 33%, 26%, and 43%, respectively. Ergocalciferol, when compared with no treatment, did not significantly increase the proportion of patients with follow-up levels >= 30 ng/ml (chi(2) P value = .80, .34, and .22, respectively). Conclusions The prevalence of vitamin D deficiency is high. but declined with time. Age, forced expiratory volume in 1 second, and season were associated with 25-OHD levels. Despite 33% of patients responding to 50 000 IU of ergocalciferol once a week, this recommendation does not adequately treat most patients with CF who have vitamin D deficiency.