High ferritin warns of bone loss

Jul 10 2012

By Laura Cowen

Individuals with high levels of ferritin, an indicator of iron stores within the body, have accelerated bone loss at the proximal femur, Korean researchers report.

"These data provide the first clinical evidence that increased total body iron stores could be an independent risk factor for future deterioration of bone mass," remark Jung-Min Koh (University of Ulsan College of Medicine) and co-authors of the study.

They evaluated the association between serum ferritin concentrations and annualized changes in bone mineral density (BMD) in 940 postmenopausal women and 789 middle-aged men aged 40 years or older who had undergone comprehensive routine health examinations with an average 3 years of follow-up.

"Despite extensive experimental and animal evidence about the detrimental effects of iron and its overload on bone metabolism, there have been no clinical studies relating iron stores," the researchers note.

They report in the Journal of Bone and Mineral Research that the mean ferritin level was significantly higher in men than in women at 76.9 versus 147.3 ng/mL.

The overall mean annualized rates of bone loss, measured by dual energy X-ray absorptiometry, in the total femur, femural neck, and trochanter were 1.14%, 1.17%, and 1.51% per year, respectively, in women and 0.27%, 0.34%, and 0.41% per year, respectively, in men.

After adjustment for potential confounders including age, weight, height, baseline BMD, smoking and drinking habits, physical exercise, and presence of the metabolic syndrome, Koh and team found that the rates of bone loss in all proximal femur sites increased significantly across increasing ferritin quartiles in both men and women.

Furthermore, women with the highest levels of ferritin were a significant 5.3 times more likely to have a vertebral fracture during the follow-up period than those with the lowest levels. Men with the highest levels also had a higher fracture incidence than those with the lowest levels, but the difference was not statistically significant.

"We believe that this study has important implications in that it clinically validates previous experimental and animal data and demonstrates that the detrimental effect of increased body iron stores on bone persist even in non-pathologic conditions," Koh et al remark.

The data may also have "clinical implications for the prevention of osteoporosis through identifying a high-risk population for future bone loss, they conclude."

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