Zinc supplementation improves bone density in patients with thalassemia: a double-blind, randomized, placebo-controlled trial.
BACKGROUND
Patients with thalassemia major (Thal) frequently have low plasma zinc, which has been associated with low bone mass.


OBJECTIVE
The objective was to determine the effect of zinc supplementation on bone mass in patients with Thal.


METHODS
Forty-two subjects (21 females aged 10-30 y) with Thal and low bone mass were randomly assigned to receive 25 mg Zn/d or placebo. Bone mineral content (BMC) and areal bone mineral density (aBMD) were assessed by using dual-energy X-ray absorptiometry, and fasting blood was collected for the measurement of plasma zinc at 0, 12, and 18 mo.


RESULTS
Thirty-two subjects, 81% of whom were transfusion dependent, completed the study (mean ± SD: 17.1 ± 5.2 y). Plasma zinc was ≤70 μg/dL in 11 subjects at baseline and increased significantly with zinc supplementation (P = 0.014). Use of intention-to-treat analysis and linear models for longitudinal data, adjusted for baseline and pubertal stage, showed that the zinc group had significantly greater increases in whole-body BMC (adjusted mean ± SE: 63 ± 15 g; P = 0.02), and aBMD (0.023 ± 0.006 g/cm(2); P = 0.04) than did the placebo group after 18 mo. Furthermore, adjusted spine and hip aBMD z scores each decreased by 0.3 SDs (both P = 0.04) in the placebo compared with the zinc group over the 18-mo study.


CONCLUSIONS
In young patients with Thal, zinc supplementation resulted in greater gains in total-body bone mass than did placebo. Zinc was well tolerated and is worthy of investigation in larger trials in Thal patients across a range of ages and disease severity. This trial was registered at clinicaltrials.gov as NCT00459732.
Departments of Hematology at the Children's Hospital & Research Center, Oakland, CA and the Children's Hospital Oakland Research Institute, Oakland, CA.
Ellen B
EB
Fung
Janet L
JL
Kwiatkowski
James N
JN
Huang
Ginny
G
Gildengorin
Janet C
JC
King
Elliott P
EP
Vichinsky
D000293:Adolescent; D000328:Adult; D015519:Bone Density / Q000187:drug effects*; D002648:Child; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D010919:Placebos; D055815:Young Adult; D015032:Zinc / Q000008:administration & dosage* / Q000097:blood; D017086:beta-Thalassemia / Q000188:drug therapy* / Q000503:physiopathology
D010919:Placebos; D015032:Zinc