Effects of Rosiglitazone on Bone in Postmenopausal Diabetic Women

• metabolic bone markers before and after the intervention,
  

• association between the changes in bone turnover parameters and plasma cytokine levels
  

Fifty-six obese, drug naive patients with type 2 diabetes mellitus were enrolled and completed the study. Twenty-six healthy subjects matched for age and body mass index (BMI) served as nondiabetic controls. All subjects were postmenopausal women with last menses at least 2 years. After the baseline measurements, all subjects were instructed to follow a weight-maintaining diet, based on ADA recommendations, and were also encouraged to walk or to jog at least 30 min daily. Subsequently, 28 of the diabetic subjects were randomly assigned to receive rosiglitazone (4 mg/day). Twenty-eight of diabetic subjects were on diet alone. The randomization procedure was based on a random sequence.

All subjects had a complete clinical examination, anthropometric measurements, and laboratory tests at baseline and at the end of the 12th week of the study. Laboratory investigations included assessment of: (i) glycemic control (HbA1c, fasting plasma glucose and insulin levels, and homeostasis model assessment (HOMA) index (22); (ii) serum bsALP and active human osteocalcin concentration (OCL) as markers of bone formation; (iii) urine deoxypyridinoline (DPD) as marker of bone resorption. Other non-specific bone markers including serum total ALP activity, urinary calcium (Ca) and phosphate (PO4) concentrations were also measured. Urine concentrations of DPD (nmol/L), Ca and PO4 (both in mmol/L) were corrected for their respective urine creatinine (Cr) concentrations in mmol/L (Urine DPD/Cr, Urine Ca/Cr and Urine PO4/Cr respectively). In addition, fasting blood samples were analyzed for plasma cytokine levels including IL-1β, IL-6 and TNF-α, and for haptoglobin levels.