Vitamin D and parathyroid hormone in relation to bone mineral density in postmenopausal women

Abstract

Background/Aim. Despite vitamin D insufficiency being widely reported, in Serbia the epidemiological data lack information regarding vitamin D status in the sera of postmenopausal women. The aim of this study was to establish the prevalence of inadequate serum 25-hydroxyvitamin D [25(OH)D] concentrations in postmenopausal Serbian women with seasonal variations of 25(OH)D, in relation to parathyroid hormone (PTH) and bone mineral density (BMD). Methods. A total of 95 postmenopausal women, mean age 65.1 ? 9.08 years, were examined. Measurements of 25(OH)D and PTH were performed both in the winter and the summer period, using electrochemiluminiscence immunoassays. BMD (g/cm2) was measured by the dualenergy x-Ray absortimetry (DXA) method on the spine and hip areas. Results. A decreased value of vitamin D (< 75 nmol/L) in 88.4% of postmenopausal women and an elevated level of PTH (> 65 pg/mL) in 25.3% of the cases were found. Elevated PTH varied individually, but was mostly increased if 25(OH)D was equal or lower than 37.6 nmol/L. 25(OH)D insufficiency was found in winter in 94.5% and in summer in 80% of the cases (p < 0.01). The mean of the PTH was higher (p < 0.05) in winter than in summer. A significant negative correlation between 25(OH)D and PTH (p < 0.001) was proved. Correlation between 25(OH)D and PTH with BMD at lumbar spine was established in the whole group, but at the femoral neck in women aged over 65 years (p < 0.05). Conclusion. Our results showed a high prevalence of vitamin D insufficiency (88.4%) among postmenopausal women. The levels of 25(OH)D and PTH changed significantly according to the season.Uvod/Cilj. Iako u svetu postoje brojne studije o insuficijenciji vitamina D, u Srbiji nema dovoljno epidemioloskih podataka o statusu vitamina D u serumu postmenopauzalnih zena. Cilj ovog istrazivanja bio je da se ispita ucestalost snizenih koncentracija 25-hidroksi vitamina D [(25OHD)] u serumu postmenopauzalnih zena u Srbiji, sezonska varijacija 25(OH)D i povezanost sa nivoom paratireoidnog hormona (PTH) i sa mineralnom kostanom gustinom (BMD). Metode. Ispitano je 95 postmenopauzalnih zena, prosecne starosti 65,1 ? 9,08 godina. Za odredjivanje 25(OH)D i PTH u zimskom i letnjem periodu korisceni su imunoloski testovi zasnovani na metodi elektrohemiluminiscencije. Mineralna kostana gustina (g/cm2) merena je metodom DXA u predelu kicme i kuka. Rezultati. Snizene vrednosti vitamina D (< 75 nmol/L) ustanovljene su kod 88,4% postmenopauzalnih zena, a povisene vrednosti PTH (> 65 pg/mL) kod 25,3%. Povecanje PTH variralo je individualno, ali je bilo najcesce kada je 25(OH)D bio jednak ili nizi od 37,6 nmol/L. Insuficijencija 25(OH)D u zimskom perodu nadjena je kod 94,5%, a u letnjem kod 80% (p < 0,01) ispitanika. Srednja vrednost PTH bila je visa (p < 0,05) u zimskom nego u letnjem periodu. Znacajna negativna korelacija je dobijena izmedju 25(OH)D i PTH (p < 0,001). Takodje, 25(OH)D i PTH znacajno su korelisali sa BMD u predelu kicme u celoj grupi, a sa vratom femura kod zena starijih od 65 godina (p < 0,05). Zakljucak. Rezultati ukazuju na visoku zastupljenost insuficijencije vitamina D (88,4%) kod postmenopauzalnih zena. Vrednosti 25(OH)D i PTH statisticki se znacajno menjaju u zavisnosti od godisnjeg doba.