Body mass index effect on total and undercarboxilated osteocalcin in normoglucemic adult men

Abstract

Obesity and osteoporosis, two of the main common chronic diseases are interconnected. Regarding, both pathologies come from the deregulation of a common mesenchymal precursor. Moreover, bone through osteocalcin (OCN) and fat tissue through leptin appear to contribute to glucose homeostasis. The objective of this study was to evaluate the effect of BMI on serum levels of total OCN andundercarboxilated OCN (ucOCN), in non-diabetic overweight and obese adult men who were divided according to quartiles of BMI(range 29.0 to 47 kg/m2). We determined ucOCN, OCN, leptin and insulin, in 54 adult non-diabetic men, having normal levels of glucose (80 to 110 mg/dL) and hemoglobin A1c (HbA1c 5.7%). Thepresence of overweight (OW) or obesity (OB) types I, II or III degree was determined according to BMI index. Glucose, HbA1c levels were measured by standard laboratory methods; OCN (ng/mL), ucOCN(ng/mL), leptin (ng/mL), insulin (uUI/L) levels by ELISA and 25hydroxyvitamin D (25OHD) (ng/mL) levels by a competitive protein-binding method.Results: The results (mean ± SD) are summarized in Table 1. Glucose ucOCN OCN CTX 25OHD Leptin InsulinOverweight 97±9 3.98±0.73 25.8±15.4 355±30 21.2±2.4 21±19 12.1±3.2T1 Obesity 99±8 4.49±1.09 18.8±6.7 313±101 20.7±6.9 19±11 12.4±4.1T2 Obesity 102±7 4.81±1.22 15.3±4.2 318±54 22.3±7.9 27±11 24.2±8.8T3 Obesity 106±3 4.31±0.59 8.3±4.1 344±8 16.8±2.8 41±22 23.4±4.1There was an increase in ucOCN and a decrease in CTX levels between OW and the three types of OB (P-.01). OCN levels decreased and Leptin increased with the increase in BMI (p-.01). Insulin increased in OBTII and OBTIII vs. OW and OBTI (p-.05).The lowest 25OHD levels were observed in TIII obesity.Conclusions: The present results suggested that BMI through leptin affects OCN concentration, which in turn influences insulin levels and glucose homeostasis.