Simvastatin Effect on Calcium and Silicon Plasma Levels in Postmenopausal Women with Osteoarthritis

Postmenopausal women more often suffered from knee osteoarthritis and its pathogenesis still remains unclear. Calcium and silicon are significant elements involved in bone and joint metabolism, especially in older people. Cardiovascular diseases are common worldwide and simvastatin is the most prescribed drug in such population of patients. The purpose of this study was to evaluate the effect of simvastatin administration on calcium and silicon concentration in the plasma of postmenopausal women with osteoarthritis. Sixty postmenopausal mild hypercholesterolemic women (mean age 61.4 years, range 54-68) were enrolled. Thirty patients received simvastatin (20 or 40 mg/day) for at least 1 year before being enrolled (simvastatin "+" group). Control group consists of remaining 30 women (simvastatin "-"group). Silicon and calcium concentrations were measured spectrophotometrically. Plasma simvastatin level was determined 3 h after the drug administration using HPLC-UV-Vis. Calcium but not silicon level was significantly lower in patients receiving simvastatin in comparison with non-statin group (1.91 ± 0.32 vs. 2.33 ± 0.19 mmol/l, p < 0.05). A weak but significant positive correlation between plasma silicon and simvastatin levels (r = 0.3, p < 0.05) was observed; this may be due to the fact that simvastatin contains silicon dioxide as an inactive ingredient. The mean simvastatin concentration was 9.02 ng/ml. All hypotheses were verified at the significance level of p < 0.05. A statistically significant decrease in the plasma calcium concentration of postmenopausal women, treated with simvastatin suggests that simvastatin may play a role in calcium metabolism in postmenopausal women with osteoarthritis. Positive correlation of simvastatin concentration with silicon level in the plasma suggests that both might prompt the positive effect of osteoarthritis treatment.