Vitamin D Metabolites and Sex Steroid Indices in Postmenopausal Women with and without Low Bone Mass

Abstract

While the independent roles of vitamin D and sex hormones in skeletal health are well established, the associations of vitamin D and its metabolites to sex hormones and their indices are less investigated. In this observational study, clinical information of 189 Saudi postmenopausal women aged ≥50 years old [N = 80 with normal bone mineral density (BMD), aged 53.3 ± 7.7 years with body mass index (BMI)= 34.1kg/m2 ± 5.8, and N = 109 with low BMD (T-score −1.0 to −2.5), aged 57.0 ± 8.2 years, BMI = 32.4kg/m2 ± 6.2] was extracted from an existing capital-wide osteoporosis registry in Riyadh, Saudi Arabia. Data included were BMD scores, serum total 25(OH)D, sex hormones, and bone turnover markers which were measured using commercially available assays. Age- and BMI-adjusted comparisons revealed significantly higher parathyroid hormone (PTH) levels as well as significantly lower testosterone and bioavailable testosterone in the low BMD group than the normal BMD group (p-values 0.04, 0.02, and 0.03, respectively). Stepwise linear regression showed that circulating testosterone levels accounted for 9.7% and 8.9% of the variances perceived in bioavailable 25(OH)D and free 25(OH)D, respectively (p < 0.01), independent of other sex hormones, sex hormone indices, and bone turnover markers. Our study suggests that androgens are significantly associated with non-conventional vitamin D metabolites and these associations may have clinical relevance in assessing risk for low BMD and osteoporosis in Arab postmenopausal women.

PTHR1 Genetic Polymorphisms Are Associated with Osteoporosis among Postmenopausal Arab Women

“…8/25/36516, and all methods were carried out in accordance with relevant guidelines and regulations. Clinical information of 600 postmenopausal women was collected from the Osteoporosis Registry Database of the Chair for Biomarkers of Chronic Disease (CBCD) at KSU, Riyadh, Saudi Arabia [ 5 , 6 , 17 ]. Participants were recruited from the outpatient clinics of the departments of orthopaedics at King Khalid University Hospital (KKUH), King Fahad Medical City (KFMC), and King Salman Hospital, Riyadh, Saudi Arabia.…”

Declining serum bone turnover markers are associated with the short-term positive change of lumbar spine bone mineral density in postmenopausal women

“… 29 25(OH)D is the main form of vitamin D stored in the body and can be measured to reflect its overall level. Al-Daghri et al 30 pointed out that the correlation between 25(OH)D and sex steroid indices may be an important mechanism affecting BMD in postmenopausal women. In this study, although there was no significant difference in the baseline and 1-year 25(OH)D levels between the two groups, the 1-year 25(OH)D level in Group 2 was significantly higher than the baseline level, confirming that 25(OH)D may play a positive role in the improvement of BMD.…”

“… 42 A decline in vertebral BMD in rodent models supports the conclusion that bone metabolic disorders are caused by magnesium deficiency. 43 Unlike Magnesium studies, some research has suggested that there are no differences in Calcium and Phosphorus levels between people with different BMD levels; 26 , 30 it is speculated that this may be because levels of mineral salts tend to be normal in patients with primary osteoporosis. 26 In our study, there were some differences in Calcium, Phosphorus, and Magnesium levels across the times and groups.…”

Electroactive Biomaterials for Facilitating Bone Defect Repair under Pathological Conditions

“…There are currently three main proposed underlying causative mechanisms of osteoporosis: i) age‐related decline in hormonal levels, particularly estrogen deficiency in older post‐menopausal women; [ 39–42 ] ii) age‐related decrease in the proliferative potential, plasticity, and number of endogenous mesenchymal stem cells; [ 43,44 ] and iii) vitamin D deficiency in older patients. [ 45,46 ]…”

“…Another causative mechanism of increased bone resorption with aging is vitamin D deficiency in older patients. [ 45,46 ] The resulting secondary hyperparathyroidism caused by vitamin D deficiency has been reported to increase bone resorption via osteoclast activation. [ 45,46 ]…”