Clinical Study Serum 25-OH Vitamin D in relation to Bone Mineral Density and Bone Turnover Nicola Napoli, 1 Rocky Strollo, 1 Delia Sprini, 2 Ernesto Maddaloni, 1 Giovam Battista Rini, 2 and Enrico Carmina 3 1 Endocrinology and Diabetes, Universit´ a Campus Bio-Medico di Roma, Via Alvaro del Portillo 21, 00128 Rome, Italy 2 Dipartimento di Medicina Interna e Specialistica (DIMIS), Universit` a di Palermo, Via del Vespro 129, 90127 Palermo, Italy 3 Endocrine Unit, Department of Medical and Biological Sciences, Universit´ a di Palermo, Via delle Croci 47, 90139 Palermo, Italy Correspondence should be addressed to Enrico Carmina; enrico.carmina@ae-society.org Received 5 January 2014; Accepted 22 June 2014; Published 7 July 2014 Academic Editor: Reina Armamento-Villareal Copyright © 2014 Nicola Napoli et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. It is unclear which vitamin D status is optimal for bone health. In this study, we aimed to assess cutofs of 25-hydroxyvitamin D (25OHD) derived by the literature (20, 25, or 30ng/mL) in relation to bone turnover and bone mineral density (BMD). Serum 25OHD, PTH, osteocalcin, bone alkaline phosphatase, and C-telopeptide were measured in 274 consecutive postmenopausal women. BMD of the lumbar spine (L1–L4) and of femoral neck were also evaluated. 50 patients had normal BMD, while 124 had osteopenia and 100 had osteoporosis. 37.6%, 56.2%, and 70.8% subjects had serum 25OHD lower than 20, 25, or 30ng/mL, respectively. No diferences in bone turnover markers were found when comparing patients with low 25OHD deined according to the diferent cutofs. However, a cutof of 25 ng/mL appeared to diferentiate better than a cutof of 30 ng/mL in those subjects with reduced femoral neck BMD. he PTH plateau occurred at 25OHD levels of 26–30ng/mL. In conclusion, vitamin D deiciency is common in Sicilian postmenopausal women and it may be associated with low BMD and increased bone turnover markers. Further studies are needed to better deine the right cutof for normal vitamin D levels in postmenopausal women. 1. Introduction Vitamin D deiciency causes defects of bone mineralization and low vitamin D status has been detected in patients with hip fractures [1–3]. While in the past it was thought that vitamin D deiciency afects mostly northern countries [4, 5] and where there is a restricted exposure to sunlight or in elderly patients [6, 7], other studies have shown that vitamin D deiciency may be common also in subtropical countries [3, 8, 9] or southern Europe [10] including Italy [11]. In a large clinical trial on raloxifene, it was found that a vitamin D dei- ciency is common in southern Europe (8.3% of the patients) [10]. In the same study, 24.3% of the postmenopausal women had low-normal vitamin D status, in a range that could be considered partial vitamin D deiciency [10]. Several studies have shown a negative correlation between BMI and vitamin D at any ages and in diferent clinical conditions. herefore, the increasing prevalence of obesity and metabolic syndrome, which are associated with decreased bioavailability of dietary and cutaneously synthesized vitamin D, is an additional factor contributing to the widespread of vitamin D deiciency [12]. It should be noted that vitamin D deiciency is associated with muscle impairment and it is one of the contributing factors of a clinical condition known as “sarcobesity.” However, there is no consensus on which levels of serum 25-hydroxyvitamin D (25OHD) should be considered abnormal [13–15]. In this study, we aimed to assess whether diferent cutofs of 25OHD-deiciency are associated with altered bone turnover or bone mineral density (BMD) in a homogeneous population of postmenopausal women living in Sicily. Sicily is the most southern part of Italy; it is surrounded by the Mediterranean Sea and characterized by sun exposure for 2/3 of the year. 2. Experimental Subjects and Methods 2.1. Study Subjects. We enrolled 274 consecutive postmen- opausal women, aged 48–65 years (mean age 57.7 ± 0.4), Hindawi Publishing Corporation International Journal of Endocrinology Volume 2014, Article ID 487463, 5 pages http://dx.doi.org/10.1155/2014/487463