Vitamin D and Bone Mineral Density in Ambulatory Women Living in Buenos Aires, Argentina

Abstract

The aim of this study was to determine possible associations between bone mineral density (BMD), 25-hydroxyvitamin D (25(OH)D) and intact parathyroid hormone (PTH). In a retrospective study we examined the case notes of free-living postmenopausal women living in our city (34 degrees S). We also report a low prevalence of vitamin D deficiency (25(OH)D < 25 nmol/1, 5.6%) and of secondary hyperparathyroidism (intact PTH > 65 pg/ml, 7.5%). Age was correlated with BMD at the lumbar spine (r = -0.25, p = 0.00038) and femoral neck (r = -0.252, p = 0.0003). Body mass index (BMI) was correlated with BMD at the femoral neck (r = 0.177, p = 0.021) but not at the lumbar spine. 25(OH)D was positively correlated with BMD at the femoral neck (r = 0.149, p = 0.036) but not at the lumbar spine. PTH was positively correlated with age (r = 0.279, p = 0.012) and negatively correlated with 25(OH)D (r = -0.322, p = 0.0036). PTH was also negatively correlated with BMD at the lumbar spine (r = -0.258, p = 0.02) and the femoral neck (r = -0.282, p = 0.011). Forward stepwise multiple regression showed that BMI, age and 25(OH)D made significant contributions to BMD at the femoral neck. PTH also showed a significant contribution to BMD at both sites. In conclusion, weak correlations found between PTH and 25(OH)D and BMD suggest these biochemical variables, among other factors, contribute to lumbar spine and femoral neck BMD.

Global vitamin D status and determinants of hypovitaminosis D

“…This study showed a cut-off level of 25(OH)D of 68 nmol/L at which serum PTH began to increase [78]. Another study in ambulatory women from Buenos Aires showed differences in 25(OH)D levels in summer (63 nmol/L) and winter (53 nmol/L) [79]. Neonates and mothers from the southernmost province had lower 25(OH)D than those from Buenos Aires [80], and a proposal for a supplementation scheme for children in that province (twice single doses of 100,000 IU ergocalciferol every 3 months during autumn and winter) resulted in a safe recovery of 25(OH) D levels [81].…”

“…Therefore, both latitude and seasons influence the degree of possible solar radiation a population may receive. The literature reports strong evidence that hypovitaminosis D is greater in winter months for all age groups in Asia [25,26], Europe [69,72,82], Latin America [79], Middle East [91], North America [153], and Oceania [142]. However, in very hot countries and where the majority of women wear veils, vitamin D levels were not significantly higher and were even lower in the summer months, as these women avoided the heat and sun by staying indoors [101,105].…”

Polymorphism in vitamin D receptor is associated with bone mineral density in patients with adolescent idiopathic scoliosis

“…Furthermore, several genetic association studies have demonstrated relationships between polymorphisms of candidate genes and decreased BMD and fracture risk [14,20,30,39,40,42 [4]. Some have shown associations between serum 25(OH)D 3 status and BMD and osteoporotic fractures [10,17], and that 25(OH)D 3 inadequacies are associated with elevated risks of osteoporosis and osteoporotic fractures [18,23].…”

High prevalence of vitamin D insufficiency in healthy elderly people living at home in Argentina

“…Several studies have been performed in Argentina to determine 25OHD levels (Ladizesky et al, 1987;Oliveri et al, 1990Oliveri et al, , 1991Oliveri et al, , 1993aOliveri et al, , 1993bOliveri et al, , 1994Plantalech et al, 1997;Fradinger & Zanchetta, 2001) and in Australia at similar latitude (Need et al, 1993(Need et al, , 2000, but none were designed to assess simultaneously the vitamin D status of elderly populations living in different regions of a country that covers 3700 km from north to south, between latitude 221S and 551S.…”