Salivary calcium concentration as a screening tool for postmenopausal osteoporosis

Aim Measurements of salivary calcium level may be a useful screening tool for osteoporosis in postmenopausal women. The purpose of this study was to clarify whether this measure is valid compared with dual‐energy X ‐ray (Bone Mineral Density) screening tools in osteoporosis. Methods A case‐control study was carried out in 40 postmenopausal women with osteoporosis ( T ‐score ≤ −2.5) and 40 women without osteoporosis ( T ‐score > −1 bone mineral density). Salivary samples were collected and calcium concentrations were measured and expressed as mg/d L . Receiver operating characteristic curve analyses was used to determine the optimal cut‐off thresholds for salivary calcium in healthy postmenopausal women. Results The cut‐off point for salivary calcium was 6.1 mg/d L . The sensitivity and specificity, respectively, for identifying women with osteoporosis, were 67.5 (95% CI 52.33–82.67) and 60% (95% CI 44.62–75.38). The area under curve ( AUC ) was 0.678 (95% CI 0.56–0.79), the positive predictive value ( PPV ) was 62.79 (95% CI 47.74–77.84) and negative predictive value ( NPV ) was 64.86% (95% CI 49.27–80.46). The positive likelihood ratio was 1.688 and the negative likelihood ratio was 0.542. Conclusions Salivary calcium concentration discriminates between women with and without osteoporosis and constitutes a useful tool for screening for osteoporosis.