Risk factors for reduced bone mineral density measurements in milk allergic patients.

BACKGROUND: Earlier studies noted that young adults with IgE-mediated cow's milk allergy (IgE-CMA) have significantly lower bone mineral density (BMD) than age- and gender-matched controls. We sought to identify additional risk factors contributing to the low BMD in IgE-CMA patients.

METHODS: Post-pubertal (defined by Tanner stage V) IgE-CMA patients (n=78, 16-30-years-old females; 17.5-30-years-old males) were evaluated prospectively for BMD using a DXA scan, serum values of bone turnover factor, and dietary and lifestyle questionnaires. Patients receiving >2 short courses of systemic steroid treatments were excluded.

RESULTS: Abnormal BMD measurements (T or Z-scores < -1.0) of the lumbar vertebrae, femoral neck or hip were noted in 60 patients while normal BMD values were present in 18 patients, despite similarly decreased calcium intakes between the groups (p=0.92). Patients with abnormal BMD were more likely to be asthmatic (p=0.014), have a lower weight z-score (p=0.007), have decreased percent caloric intake derived from fat and increased carbohydrate intake (p=0.01 and p=0.03, respectively), in comparison to normal BMD group. Serum values of bone turnover were similar between the groups. On multivariate regression analysis only asthma significantly (p= 0.006) increased risk for osteopenia and osteoporosis (OR (95 CI) 38.5 (2.8-500). Fitting continuous z-scores into a regression model, both asthma and weight z-score were significant (adjusted r2 =0.272). Asthma was significantly overrepresented in osteopenic and osteoporotic subpopulations while decreased weight only in patients with osteoporosis.

CONCLUSIONS: In the context of a low calcium intake, asthma and weight are independent risk factors for decreased BMD in IgE-CMA patients. This article is protected by copyright. All rights reserved.