Carboxylated Osteocalcin and Adiponectin Correlate with Glycated Hemoglobin and 25(OH) Vitamin D Levels in Saudi Females with Type 2 Diabetes Mellitus Following Ingestion of Vitamin D Supplements
Suhad M. Bahijri *
Department of Clinical Biochemistry, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia. and Saudi Diabetes Study Research Group, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia.
Safaa Qusti
Biochemistry Department, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia.
Fatemah Khormi
Biochemistry Department, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia.
Khalid Al-Shali
Saudi Diabetes Study Research Group, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia. and Department of Internal Medicine, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia.
Hanan Jambi
Saudi Diabetes Study Research Group, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia. and Department of Nutrition, Faculty of Home Economics, King Abdulaziz University, Jeddah, Saudi Arabia.
Enayat Hashem
Department of Clinical Biochemistry, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia. and Saudi Diabetes Study Research Group, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia.
*Author to whom correspondence should be addressed.
Abstract
Background: Type 2 diabetes (T2D) is one of the fastest growing public health problems worldwide. Evidence linking vitamin D (VTD) status and T2D was reported. However, its role, and whether it acts directly or through stimulating synthesis of osteocalcin is still unclear. Vitamin D deficiency is common amongst Saudi adults. However, vitamin D supplement is not part of usual management regimen for diabetic patients.
Objectives: To study: 1-The effect of self- administered minimum dose of vitamin D supplements on glycemic control, insulin sensitivity, and lipids profile in T2DM females, 2-The relationship between serum levels of VTD and different forms of osteocalcin (OC), and the active circulating form of adiponectin.
Subjects and Methods: Sixty T2DM females were recruited to form two groups matched in age and body mass index (BMI). Group A (GA) was the vitamin supplemented group, with a minimum of 3 months intake of cholecalciferol (400IU/day), while Group B (GB) was the control group receiving no supplements. Fasting blood samples were drawn for the measurements of glucose, lipids profile, insulin, glycated hemoglobin (HbA1c), 25(OH) vitamin D, total OC, carboxylated OC (cOC), uncarboxylated OC (ucOC), and High molecular weight adiponectin (HMWApn).
Results: Means of 25(OH) vitamin D, triglycerides, total OC, cOC and HMWApn were all significantly higher in Group A compared to corresponding means in Group B, while mean HbA1c was significantly lower (P< 0.05 in all cases). VTD correlated positively with total and cOC in both groups. However, it correlated positively with HMWApn, and negatively with HbA1c in Group A only. No correlation between VTD and ucOC was found. cOC correlated highly positively with HMWApn, and negatively with HbA1c in both groups.
Conclusion: VTD supplemented subjects showed better glycemic control, possibly indirectly by stimulating the synthesis of osteocalcin, and hence adiponectin. Caboxylated OC is most likely the active form. Therefore, vitamin K status must be monitored.
Keywords: Vitamin D, glycemic control, osteocalcin, carboxylated osteocalcin, adiponectin