The study was approved by the Ethical Committee of Ataturk University Faculty of Medicine and written informed consent was obtained from the parents of all participants. This longitudinal study was conducted between March 2007 and February 2008. The study group consisted of otherwise healthy children aged 2-24 months whose body weight and height values were between 3rd and 97th percentiles, and who were diagnosed as VDDR. Clinical rickets was diagnosed in children who showed two or more of the following findings: craniotabes (in infants over 2 months), bilateral widened wrists, frontal bossing, bowing of the legs, pathologic fractures, hypocalcemic tetany, hypocalcemic convulsions, and Harrison’s sulcus. Infants with familial forms of rickets and those with secondary VDD due to kidney, liver and gastrointestinal system diseases were excluded from the study.
The anthropometric indices of the patients were recorded before and after therapy. Weight was measured using an electronic scale (Seca Model 770, Hamburg, Germany). Length (±0.1 cm) was measured using a body-length measurer by a paediatrician. Body mass index (BMI) was calculated as body weight (kg)/square of length (m2). Radiological and laboratory investigations were carried out in all cases diagnosed as VDDR. Radiological evidence of rickets by radiography of the left wrist included two or more of the following signs: generalized osteopenia, fraying and cupping of the distal ends of the radius or ulna. To confirm the diagnosis of VDDR biochemically, serum calcium (Ca), phosphorus (P), alkaline phosphatase (ALP), serum intact parathyroid hormone (iPTH), and 25-hydroxyvitamin D (25(OH)D) were measured in all patients. VDD was defined as a serum 25(OH)D level less than 10 ng/ml (9
All patients were treated with an intramuscular single dose (300.000 IU) of vitamin D3, and 50 mg/kg/day of elementary calcium lactate administered orally for ten days. The patients were invited to the clinic one month after the initiation of therapy. Serum Ca, P, ALP, iPTH, and 25(OH)D were re-measured and radiography of the left wrists were re-evaluated. If the serum Ca, P, and 25(OH)D concentrations increased while serum iPTH and ALP concentrations decreased compared to pre-treatment values, and if a calcification zone along the metaphyseal-diaphyseal border was detected radiologically, the patient was considered to be healed.
Measurement of serum adiponectin levels, and biochemical and hormonal parameters
Blood samples were obtained before and after treatment. Biochemical tests were studied immediately. For hormone measurements, serum samples were transferred into Eppendorf tubes and stored at -20 oC until assayed. Adiponectin was measured by ELISA using the kits and protocol from ORGENIUM Laboratories, Inc. (AviBion Human Adiponectin (Acrp30) ELISA Kit, Helsinki, Finland). Serum Ca, P, and ALP levels were measured using the calorimetric method. Serum iPTH was determined with chemiluminescence enzyme immunoassay method using the iPTH kit (IMMULITE 2000 Intact PTH Kit, DPC Co., USA). Serum 25(OH)D level was determined by competitive binding RIA (Gamma-B, 25(OH)D RIA, Immunodiagnostic Systems, UK).
All the calculations were made by using SPSS (version 15.0, Chicago, IL, USA) for Windows. The Wilcoxon-Smirnov test was used for the significance level of the differences between longitudinal patterns. Correlations between two variables were tested by Pearson’s correlation coefficient. The results were expressed as mean±SD; p<0.05 was considered statistically significant.