Serum Osteocalcin, Zinc Nutritive Status and Bone Turnover in Children and Adolescents with Type1 Diabetes Mellitus

Abstract

Background: Patients with DM have various bone disorders, including osteopenia or osteoporosis. Objective: This study aimed to examine the relationship between zinc dietary intake and osteocalcin level as a biochemical marker of bone turnover in patients with type1 DM. Methods: Serum osteocalcin was assayed by ELISA and serum zinc was assayed using direct colorimetric method in 60 children and adolescents with type 1 diabetes. The results were compared with 40 healthy controls well matched in age, gender and pubertal staging. Participants recorded their dietary intake for 3 days, Zinc content was determined with the diet analysis program (version1, 1995). Results: Diabetic patients showed significantly lower serum osteocalcin compared to control (P = 0.00), while there was no significant difference between patients and control as regards serum zinc and daily dietary zinc intake (P = 0.78 and P = 0.94) respectively. There was no effect of gender on serum osteocalcin, serum zinc and daily dietary zinc intake (P = 0.92, P = 0.15 and P = 0.39) respectively. Patients with HbA1c >7.5 (poor metabolic control) showed significantly lower serum osteocalcin level compared to patients with HbA1c <7.5 (good metabolic control) (P = 0.014). Patients with positive history of boneache showed significantly lower serum zinc and daily dietary zinc intake (P = 0.03 and, P = 0.046), respectively, while there was no significant difference as regards serum osteocalcin (P = 0.37). Serum osteocalcin was positively correlated with serum zinc (P = 0.01), daily dietary zinc intake (P = 0.003) and it was negatively correlated with HbA1c (P = 0.01). Conclusion: Reduced serum osteocalcin could be used as a measure to detect early metabolic bone changes in patients with type 1 diabetes. Optimization of blood sugar together with good zinc dietary intake may help to improve osteoblasts activity and prevent bone complications.