Salivary calcium concentration as a screening tool for postmenopausal osteoporosis
Correspondence: Associate Professor Maryam Rabiei, Department of Oral Medicine, Dental School, Guilan University of Medical Science, Emem Khomeini St., Rasht, Iran.
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.
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/dL. Receiver operating characteristic curve analyses was used to determine the optimal cut-off thresholds for salivary calcium in healthy postmenopausal women.
The cut-off point for salivary calcium was 6.1 mg/dL. 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.
Salivary calcium concentration discriminates between women with and without osteoporosis and constitutes a useful tool for screening for osteoporosis.