Association of elevated circulating iron with bone mineral density and bone turnover markers in postmenopausal Saudi women with and without osteoporosis
Afnan Ghaleb, Saba Abdi, Sobhy Yakout, Syed D. Hussain, Shaun Sabico, Omar S. Al-Attas, Nasser M. Al-DaghriAbstract
Objectives
To explore the associations of serum iron indices with bone mineral density (BMD) and bone turnover markers (BTMs) in postmenopausal Saudi women with and without osteoporosis.
Methods
This cross-sectional study included 184 postmenopausal women aged ≥45 years (75 osteoporotic and 109 controls). Anthropometric and biochemical parameters were assessed. Serum iron, transferrin, total iron-binding capacity (TIBC), and transferrin saturation (TSAT) were measured. Bone-specific alkaline phosphatase (BsALP), osteocalcin, and osteopontin were evaluated. Participants were classified based on serum iron levels (50–170 μg/dL [normal circulating iron] and >170 μg/dL [elevated circulating iron]). BMD was measured at the lumbar spine and femur by dual-energy X-ray absorptiometry (DXA).
Results
Osteoporotic women had significantly lower BMD at the spine and femur (p<0.001). Elevated circulating iron was observed in 54.3 % of participants. Serum iron weakly correlated with osteocalcin (r=0.17, p=0.02) and osteopontin (r=0.17, p=0.049) only in unadjusted analyses. All observed associations were not supported by the primary adjusted analysis.
Conclusions
The primary adjusted analysis showed no statistically significant association between elevated circulating iron and osteoporosis risk. The observed weak associations between serum iron and selected bone turnover markers should be considered exploratory. Findings do not support an independent association between elevated circulating iron and postmenopausal osteoporosis.