Introduction and Objectives The association between low vitamin D levels and increased severity/susceptibility to TB infection due to suppression of innate immunity is well known. In the United Kingdom, low levels of background ultraviolet B radiation limit the photoconversion of 7 dehydrocholestrol in skin to cholecalciferol (vitamin D3). In addition the majority of paediatric TB cases in the UK occur in non-Caucasian patients who by nature of their skin colour are less able to absorb the UV radiation. Current guidelines do not suggest routine checking of serum 25-dihydroxyvitamin D (25(OH)D); a reliable measure of body stores of vitamin D, in paediatric TB cases and providing Vitamin D supplementation as required. We hypothesised that all paediatric TB patients require screening for Vitamin D deficiency and that many would benefit from supplementation.
Methods This is a prospective cohort study. Between January 2009 and June 2010, all paediatric TB cases were prospectively recorded into a hospital database. Data collected include age, sex, serum concentrations of 25(OH)D, calcium (Ca), phosphate (P), alkaline phosphatase (ALP) and parathyroid hormone (PTH).
Results 45 patients (18 males) were diagnosed with TB over the 18 month period. The mean age was 7.5 years (range 5 months to 17 years). The results for Vitamin D were not available in 5 patients (3 in progress, 2 not performed). Of the 40 patients with results available, 39 (97.5%) were found to have low levels of 25 (OH)D and were commenced on supplementation. Of these, 29/40 (72.5%) had profound Vitamin D deficiency (25(OH)D levels <10 ng/ml). Of these 29 patients, 15 had high PTH levels, 2 had low Ca (no data for one patient), 4 had low P levels and 5 had elevated ALP levels. One patient had radiologically confirmed rickets.
Conclusions Our study supports the incorporation of routine Vitamin D screening into the current guidelines for the management of TB, especially as TB itself can worsen pre-existing vitamin D deficiency.