Relationship between Serum Ferritin and Bone Density in Healthy Women and Relationship of Iron Overload to Bone Metabolism in Postmenopausal Women with Fragility Fractures of the Hip
|Keywords||Ferritins Iron overload Bone mineral density OsteoporosisHip fractures Osteoporosis postmenopausal|
Part ⅠRelationship between serum ferritin and bone density in healthy womenObjective To study how increased iron storage in women influenced bonemetabolism.Methods This study composed of435women from January2011to December2012,whose serum levers of ferritin (Fer) were measured and remarked. Bone mineraldensity(BMD) in femur and lumbar spine were measured by dual-energy X-rayabsorptiometry. We observed serum Fer and BMD alteration with age. Then wecategorized subjects into several groups according to the level of ferritin, andNon-conditional Logistic Regression Analysis was used to evaluate the risk of osteopenia.At last, associations between Fer and BMD in all areas were measured by multipleregression analyses and partial correlation.Results The serum Fer level was low and stable in women before the age of40,gradually increased in women aged41–49, rapidly rose in women aged50–65, and wasremaining steady high after the age of65. However, the BMD was high before the age of50, rapidly fall in women aged50–65, and kept low after the age of65. In analysis byquintiles, after adjusting confounding factors, compared with the individuals in the lowestquintile, those in the highest quintile were more than twice as likely to suffer osteopenia infemur neck and L1-L4(OR:2.82;95%CI1.25-6.38and OR:2.04;95%CI0.92-4.51). Age,weight, serum Fer and BMI were associated with BMD after using multiple regressionanalyses. Then adjusting age, weight and BMI, serum Fer also showed negative correlationwith BMD of all regions (P<0.05).Conclusion The concentration of serum Fer increased and BMD decreased with age.With increasing with the concentrations of Fer, the BMD decreased and the risk of osteopenia was higer and higer. PartⅡRelationship of iron overload to bone metabolism in postmenopausalwomen with fragility fractures of the hipObjective To study relationships between serum ferritin and bone metabolism inpatients with hip fragility fractures..Methods This cross-sectional study included76postmenopausal women with hipfracture. The mean age of the women was (73±10) years (range,55-93years) and themean duration of menstruation was (22±10) years (range,5-50years). Serumconcentrations of ferritin, transferrin, alkaline phosphatase (ALP), amino-terminalextension peptide of type Ⅰ collagen (P1NP), and C-terminal telopeptides of type Ⅰcollagen (β-CTX) and femoral and lumbar bone mineral density by dual-energy X-rayabsorptiometry were measureed. Bone metabolism was compared between normal andelevated ferritin groups with t-tests. Pearson linear, partial correlation, and multipleregression analyses examined associations between iron-and bone-related markers.Results Serum ferritin concentrations raised to (230.0±146.5)ng/ml, transferringconcentrations reduced to (1.89±0.33)g/L. P1NP concentrations raised to (60.9±31.9)ng/ml when the concentrations of serum ALP and β-CTX were in the normal range.T-scores for bone mineral density in the femoral neck (-1.97±1.06) and lumbar (-2.13±1.15)were below the normal ranges(-1.0～1.0). The subjects were divided into two groupsaccording to serum ferritin concentration, normal(serum ferritin concentrations≤150ng/ml,n=25) and elevated(serum ferritin concentrations＞150ng/ml, n=51). Patients with higher(vs. normal) ferritin concentrations had lower bone mineral density in femoral neck andlumbar (t=3.13、2.89, P <0.01), and higher P1NP, β-CTX concentrations（t=-2.38、-3.59，P <0.05）. In partial correlation analysis adjusted for confounders, serum ferritinconcentrations were correlated negatively with bone mineral density in both femoral neckand lumbar (R=-0.335、-0.295, P<0.05), and positively with P1NP and β-CTX (R= 0.467、0.414, P<0.05), but not ALP (R=0.188, P>0.05). Transferrin concentrations tendedto be correlated positively with bone mineral density in both femoral neck and lumbar (R=0.444、0.262, P<0.05) and negatively with ALP, P1NP and β-CTX(R=-0.326、-0.285、-0.278, P<0.05).Conclusion Iron overload has a high prevalence in postmenopausal women withfragility fracture. Increased iron stores, which might lead to bone loss and lower bonemineral density by enhancing the activity of bone turnover, could be an independent factorto take effects on bone metabolism on postmenopausal women.