Slight decrease in bone mineralization in cow milk-sensitive children

Abstract

Background: Patients with cow milk allergy (CMA) are potentially at risk for osteopenia because their milk-free diet usually contains a low calcium content. In our study, different parameters of bone mineralization in children with CMA were investigated.

Patients and methods: Twenty-seven CMA patients (mean age, 4.3 years; range, 3-8 years) were enrolled in the study. During a mean milk-free diet period of 11.8 months, children were fed extensively hydrolyzed or soy-based formulas. After a milk challenge test, 7 patients showed allergic symptoms, and the other 20 children had transient CMA. From the sera of all patients, the levels of sodium, potassium, chloride, calcium, phosphate, and magnesium ions, as well as alkaline phosphatase (AP), parathyroid hormone (PTH), osteocalcin, and beta-crosslaps, were determined. These values were compared with those of 20 healthy age-matched controls. Bone mineral density was measured as well.

Results: The AP and PTH concentrations were higher in CMA patients than in the control group (AP: 610.2 U/L vs. 499.7 U/L, P < 0.01; PTH: 1.56 pmol/L vs. 0.83 pmol/L, P< 0.03), but all values were in the normal range. The osteocalcin concentration was similar in both groups, and the beta-crosslaps concentration was lower in CMA patients than in controls (0.92 vs. 1.47 ng/mL, P< 0.001). The mean Z score of bone mineral density in patients with CMA was -0.6. In 10 cases, the Z score was less than the -1 SD value. On the basis of the Z score, CMA patients were divided into two groups. The PTH concentration was significantly elevated in the group with lower Z score (2.24 pmol/L vs. 1.16 pmol/L; P< 0.03).

Conclusion: The results suggest that, in children with CMA who are on a cow milk-free diet, slight disturbances of bone mineralization can be observed by osteodensitometry.