Parathyroid hormone and optimal vitamin D status in postmenopausal women

Aim: Low serum vitamin D and calcium levels as well as high parathyroid hormone (PTH) levels are the most important risk factors in osteoporosis. The aim of our study was to estimate the optimal vitamin D status needed to prevent a rise in PTH concentrations in postmenopausal women. Materials and methods: A total of 197 postmenopausal women who were at the menopausal period for at least 1 year and who had body mass indexes (BMIs) <25 kg/m(2) were recruited between November 2011 and February 2012. Patients were evaluated by dividing them into 4 age groups (39-50 years, 51-60 years, 61-70 years, and >70 years). Results: The mean age of patients was 60.8 +/- 10.9 years. Serum 25-hydroxyvitamin D3 [25(OH) D3] levels were lower than 10 ng/mL in 94 patients (47.7%) and lower than 20 ng/mL in 167 (84.8%) patients. The mean vitamin D level was lowest in group 2 (51-60 years), but the difference was not statistically significant (P = 0.57). PTH levels were higher than 75 pg/dL in 52 patients, and 65.4% of those patients (n = 34) had vitamin D insufficiency (<10 ng/mL). Conclusion: Vitamin D insufficiency was very common in our study population (84.8%). Treatment should be aimed at achieving a 25(OH) D3 level, at which no further suppression of PTH occurs. Further studies are needed to increase awareness among physicians that with optimal vitamin D levels a rise in PTH and subsequent bone loss is prevented.