Endocrine Abstracts

Clinical, epidemiological and in-vitro studies have found evidence for an association between Vitamin D and diabetes. Vitamin D receptors are found on pancreatic beta-cells, suggesting they have a role in glycaemic control. Vitamin D analogues inhibit inflammatory cytokines involved in destruction of Beta-cells. This study aimed to assess the relationship between Vitamin D and glycaemic control, as measured by HbA1C, in a Type 1 (T1) diabetic paediatric population. HbA1C values were recorded for each patient from diagnosis to recruitment and combined to determine monthly HbA1C variation in the study population. Information on monthly daylight hours in Manchester was obtained from a meteorological website (the weather channel) and cross-correlated with monthly HbA1C. 25(OH)D3 was measured at recruitment. 53 patients (28 male) were recruited (mean age 12.5 yrs, range 3.7–19.3). There was an inverse relationship between monthly HbA1C and daylight hours (r=−0.5). When evaluating this cross correlation in time series analysis, lagging the daylight hours behind the HbA1C series was associated with a positive correlation (r=+0.109). 84% of patients were 25(OH)D3 deficient (14.9 ng/ml, range 7.7–26.6) including all of the South-Asian children (n=11). There was a significant (P<0.01) negative relationship between HbA1C at recruitment and 25(OH)D3 level in Caucasian children, and a negative trend in South Asians. 25(OH)D3 level was found to predict 14.9% of the HbA1C value in Caucasian children. In this paediatric diabetic population, we have shown that daylight hours (as a surrogate for UVB radiation) and hence 25(OH)D3 impact on HbA1C values 3 months later. We have also shown that 25(OH)D3 deficiency is very common in these children and that Vitamin D levels are inversely related to HbA1C. Given the prevalence of deficiency and the potential benefit to glycaemic control, we suggest that measurement of Vitamin D and treatment of deficiency should form part of routine care in T1 diabetic children.

Declaration of interest: There is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.

Funding: No specific grant from any funding agency in the public, commercial or not-for-profit sector.