Endocrine Abstracts

Background: There are limited data in paediatric population on the association between vitamin D deficiency/treatment and glucose/insulin metabolism.

Objective and hypotheses: This study aimed to investigate the effect of vitamin D therapy on glucose homeostasis, insulin resistance and bone turnover, in children with vitamin D deficiency.

Method: 22 children aged 3 months to 10 years (nine males) who were diagnosed with vitamin D deficiency were recruited from August 2011 to October 2013. Treatment consisted of 6 weeks of 5000 IU units cholecalciferol orally once a day. At baseline and completion of treatment serum 25 hydroxyvitamin D (25OHD), parathyroid hormone (PTH), alkaline phosphatase (ALP), serum collagen type 1 cross-linked C-telopeptide (CTX), HbA1c, sex hormone binding globulin (SHBG), fasting insulin, fasting blood glucose, and homeostasis model assessment index-estimated insulin resistance (HOMA-IR) were measured.

Results: After treatment, 25OHD had increased to a median of 126 from 28 nmol/l (P=0.00). PTH decreased from a median of 5.5 to 4.1 pmol/l (P=0.001). ALP also decreased significantly, median 236 to 195 u/l (P=0.03). There was a non-significant reduction in CTX from a median of 1.98 to 1.76 ng/ml (P=0.4) and SHBG from a median of 121 to 116 nmol/l (P=0.3). There was no change in fasting glucose (median 4.3 and 4.4 mmol/l, P=0.8) or HbA1c (median 33.5 and 34 mmol/l, P=0.5), There was a trend towards a reduction in both insulin levels and insulin resistance, with the median insulin falling from 11.1 to 8.1 μIU/ml and HOMA-IR falling from 1.84 to1.59, however this was not statistically significant (P=0.7 and 0.9 respectively). There was a weak negative correlation between vitamin D deficiency and elevated PTH at the base line (r_s, −0.19) and insulin level after treatment (r_s, −0.22).

Conclusion: There is no clear evidence of an abnormality of insulin sensitivity with no significant change on vitamin D replacement.