Ferritin levels in postmenopausal women do not seem to play a significant role in osteoporosis.

To the Editor: Osteoporosis and its complications are increasingly becoming worldwide public health concerns. Lower ferritin levels are a sign of iron deficiency anemia. We investigated levels of ferritin in osteoporotic postmenopausal women.

Sixty-seven postmenopausal women aged 56.51 [+ or -] 7.07 years who were living in Kahramanmaras city and admitted to our osteoporosis outpatient department were included in the study. Participants were divided into two groups according to their T scores. Based on the World Health Organization classifications, 38 had osteoporosis, and 29 did not.

Lumbar spine and hip densitometry were measured by dual-energy x-ray absorptiometry, which was calibrated daily. Ferritin was measured via the chemiluminescent method (hormone analyzer, Beckman Access, Chaska, MN).

Age, menopause age, number of births, body mass index, and serum calcium and phosphate were similar in both groups. Alkaline phosphatase levels were higher in group I than in group II, which was statistically significant (P = 0.006), but ferritin levels between the groups were not statistically different (66.19 [+ or -] 48.92 ng/mL versus 52.5 [+ or -] 39.52 ng/mL) (P > 0.05).

In pediatric thalassemic patients, iron overload (ferritin) is responsible for delayed bone age and defective mineralization. (1) It was demonstrated that iron-treated rats had negative effects on bone formation (2) and osteoporosis has been reported in patients with hemochromatosis. (3) Ferritin is known to be more specific than circulating iron as a marker of bone marrow status. In our study, levels of ferritin were higher (but not as high as in hemochromatosis) in women with osteoporosis, although this was not statistically significant. Again, ferritin was found to be inversely related to the mineral apposition rate (4), and accordingly, iron overload appeared to have a significant contribution in patients who had sustained fracture of the femoral neck. (5)

Although it is generally accepted that iron overload may give rise to less mineralization especially in thalassemic patients, ferritin levels in our study population were not found to be statistically different between the osteoporotic and control group.

Mehmet Akif Buyukbese, MD

Ercan Cetinus, MD

Ali Cetinkaya, MD

Sukru Aras, MD

Department of Internal Medicine

Faculty of Medicine

Kahramanmaras Sutcu Imam University

Kahramanmaras, Turkey

References

1. Mahachoklertwattana P, Sirikulchayanonta V, Chuansumrit A. Bone histometry in children and adolescents with beta-thalassemia disease: iron-associated focal osteomalacia. J Clin Endocrinol Metab 2003;88:3966-3972.

2. Takeuchi K, Okada S, Yukihiro S. et al The inhibitory effects of aluminum and iron on bone formation--in vivo and in vitro study. Pathophysiology 1997;4:161-168.

3. Roudier G, Hany Y, Louboutin JY, et al. Histomorphometric et manifestations articulaires de l'hemochromatose idiopathique. Rev Rheu Mall Osteoartic 1979;46:91-99.

4. Canavese C, Barole S, Gurioli L. Correlations between bone histopathology and serum biochemistry in uremic patients on chronic hemodialyses. Int J Artif Organs 1998;21:443-450.

5. Schnaid E, Mac Phail AP, Sweet MP. Fractured neck of femur in black patients: a prospective study. J Bone Joint Surg Br 2000;82:872-875.