Vitamin D abnormalities and bone turn over analysis in children with epilepsy in the Western Cape of South Africa

•The first sub-Saharan African study of vitamin D levels in children with epilepsy.•Children on enzyme-inducing ASMs have lower levels of Vitamin D2 and D3 levels.•Children on enzyme-inducing ASM should be assessed for vitamin D deficiency. Purpose: The effects of antiseizure medications (ASMs) on bone metabolism is inconsistent. Most studies are in high income settings and none from sub-Saharan Africa. Methods: A hospital based cross-sectional study in a paediatric epilepsy service with a comparison group assessed vitamin D metabolism. Results: Seventy-five children with epilepsy and 75 comparison group were recruited. Median age for children with epilepsy was 9 years (range 1–17 years) and controls 3 years (range 1–12 years). Vitamin D deficiency occurred in 11(16.2%) children with epilepsy versus 6 (8.8%) control group (p = 0.29). Vitamin D insufficiency occurred in 30 (44.1%) children with epilepsy compared to 27(39.7%) control group. Children on ASMs had lower mean vitamin D levels than the control group (p = 0.02). Children on enzyme-inducing ASMs had lower mean vitamin D levels (p = 0.08), vitaminD2 (p = 0.0018), vitaminD3 (p = 0.004), serum phosphate levels (p = 0.000), and higher mean parathyroid hormone levels (p = 0.03) compared to controls. There was no difference in dietary intake and ancestry, although the dietary content of both groups was low in vitamin D products. Conclusions: Low vitamin D levels were common in children from both groups, but statistically lower for the children on ASMs. Children on enzyme-inducing ASMs need screening for vitamin D deficiency. The literature supports extending this for all children on ASMs. This is the first study to report that children on enzyme-inducing ASMs have lower levels of Vitamin D2 and D3 levels, probably as result of increased destruction of vitamin D. Improved vitamin D intake for children in vulnerable settings is important.