Endocrine Abstracts

Objectives: This prospective study aimed at investigating (1) the prevalence of vitamin D deficiency and insufficiency in diabetic adolescents and children in a multi-ethnic cohort, and (2) any association between vitamin D status and ethnic background, glycaemic control (HbA1C), biomarkers of metabolic bone health and lipids.

Methodology: Venous blood was drawn from 199 patients with type 1 diabetes (mean age ± SD, 8.2 ± 3.7 years) and 48 patients with type 2 diabetes (mean age ± SD, 12.7 ± 2.7 years) during their outpatient appointments in a tertiary hospital. Vitamin D status was classified according to serum 25-hydroxyvitamin D (25OHD) concentrations as deficient (less than 12 ng/ml), insufficient (12-20 ng/ml) or sufficient (more than 20 ng/ml) (Munns et al, 2016). Concentrations of biomarkers were measured on Abbott Alinity (calcium, magnesium, phosphate, alkaline phosphatase, HbA1C, total cholesterol, LDL-cholesterol and HDL-cholesterol) and Beckman Access II [25OHD and parathyroid hormone (PTH)] automated analysers.

Results: Vitamin D insufficiency (25OHD from 12 to 20 ng/ml) was highly prevalent in both type 1 (42%) and type 2 (50%) diabetes patients, whereas vitamin D deficiency (25OHD <12 ng/ml) was detected in 11% of type 1 and 15% of type 2 diabetes patients respectively. Deficiency or insufficiency of vitamin D was particularly common in the Indian and Malay ethnic groups. Patients of Indian extraction had the lowest mean (± SD) serum 25OHD among all four ethnic groups: 16.1 (± 5.6) ng/ml and 14.1 (± 3.8) ng/ml in type 1 and type 2 diabetes patients respectively. Among type 1 patients, Malays had lower 25OHD than the Chinese (P<0.01) and Others (P<0.05) ethnic groups. Vitamin D deficiency was found to be associated with lower calcium (P<0.001) and higher PTH (P<0.001) concentrations compared with the sufficiency group (25OHD >20 ng/ml) in type 1 diabetes patients but not in type 2 patients. Concentrations of magnesium, phosphate, alkaline phosphatase, HbA1C, total cholesterol, HDL-cholesterol and LDL-cholesterol were not associated with 25OHD in either of the two types of diabetes patients.

Conclusions: Statistically significant differences in 25OHD concentrations were detected among the four ethnic groups. Ethnicity is a risk factor for vitamin D deficiency in both types of diabetes. Vitamin D deficiency was also associated with biomarkers of poorer metabolic bone health (lower calcium and higher PTH) in type 1 diabetes patients.

Reference: Munns et al. (2016) Hormone Research in Paediatrics 85:83–106.