Bone mineral density in children with moderate to severe atopic dermatitis

Background Low bone mineral density (BMD) has been reported in 30.4% of adult patients with atopic dermatitis (AD). Objective The aim of this study was to determine the prevalence of low BMD in children with moderate to severe AD and to investigate the relation between BMD and corticosteroid and cyclosporine therapy. Methods Lumbar spine BMD was measured by dual-energy X-ray absorptiometry in 60 children (age 5-16 years) with moderate to severe AD. BMD (in g/cm2 ) was expressed in Z-scores, the number of SD above or below the mean value of an age- and sex-matched reference population. In children, low BMD was defined as a Z-score less than –2. Information on lifestyle parameters and bone fractures were collected by use of a standardized questionnaire. The cumulative dose of corticosteroids and cyclosporine therapy was calculated for the previous 5-year period. Results Three patients (5%) had low BMD; one patient (1.7%) had osteoporosis. The observed prevalence of low BMD in this study (6.7%; 95% confidence interval 1.8%-16.2%) does not differ from the expected prevalence of low BMD in the general population ( P = .06). Overall, use of topical corticosteroids in the previous 5 years was not associated with a decrease in BMD (Z-score). When children received additional systemic treatment (oral corticosteroids and/or cyclosporine) in the previous 5 years, BMD decreased, although the decrease was not statistically significant. Correction for lifestyle parameters did not change these associations. Limitations The number of patients studied was limited. The cumulative dose of corticosteroids and cyclosporine therapy was only registered for the previous 5 years, and relatively low amounts of topical corticosteroids were used. The definition of low BMD differs between adults (Z-score < –1) and children (Z-score < –2). Because there is no Dutch BMD reference population for children, normative BMD references were obtained from a different population (US children). Conclusions Low BMD did not occur more frequently in this population of children with moderate to severe AD compared with the general population. Use of topical corticosteroids in the previous 5 years was not associated with a decrease in BMD.