Serum ferritin levels and bone mineral density in the elderly

Background: Iron overload influences negatively on bone mineral density (BMD) but the results of studies regarding serum ferritin (SF) and BMD are conflicting. This study aimed to determine the association of SF and BMD in the elderly. Methods: All participants of the Amirkola cohort selected between 2011-2012, aged >= 60 years were classified as high or normal (<= 200ng/ml) SF. BMD at femoral neck and lumbar spine was determined by dual energy x-ray absorptiometry (DXA) and the results were expressed as BMD g/cm(2) and BMDT-score. Multiple logistic regression analysis with calculation of odds ratio (OR) and 95% confidence interval was used to estimate the association of low BMD (LBMD) defined as BMD T-score < -1 with SF. Results: 1089 subjects (women, 44.7%) were studied. High SF was observed in 366 (33.6%) and LBMD in 874 (80.2%) subjects. The two groups of SF were similar regarding biochemical parameters and demographic characteristics except MetS, overweight/obesity and diabetes which were more prevalent in high SFgroup. BMD g/cm(2) at both measurement sites was significantly higher (P=0.001 for both) and the prevalence of LBMD was significantly lower (74.1% vs 83.1%, P=0.001) in high SF group by OR=0.60 (0.44-0.81). After adjustment for all biochemical and demographic variables, the association remained significant by adjusted OR=0. 68 (0.49-0.94). Conclusions: These findings show a negative association between high SF and LBMD indicating a beneficial effect of high SF in the elderly. Regarding detrimental effect of iron overload on bone mass, these findings require further studies.