Cross-sectional study on bone density-related sonographic parameters in children with asthma: correlation to therapy with inhaled corticosteroids and disease severity

The aim of this study was to screen asthmatic children for bone density-related sonographic parameters on the calcaneal bone. Findings were correlated to therapy with inhaled corticosteroids (ICS) as well as with asthma severity (AS), concomitance and severity of atopic dermatitis (AD), and rhinitis (AR). We enrolled 173 children with AS1-3 consecutively; 44% (AS1) had not received any ICS medication; 56% (AS2 and −3) received ICS therapy for ≥6 months (medium daily dose, 286 μg fluticasone-proprionate-equivalent/maximum 500 μg); and in addition 38% (n = 65) presented with AD and 66% (n = 115) with AR. Broadband ultrasound attenuation (BUA) and speed of sound (SOS) results were compared to regional normative values of 3299 children obtained with the identical system. ICS-treated children showed a tendency toward reduced age-, weight-, and height-adjusted standard deviation scores (SDS) for SOS compared to children without ICS treatment, which tendency did not reach statistical significance and was not as consistent for BUA (mean of ICS-treated children compared to our controls: SOS-SDS, −0.29/−0.31/−0.30; BUA-SDS, −0.23/−0.17/−0.05). For ICS-treated children, the proportion of patients with BUA and SOS values below −1 SDS was statistically significant higher for age-adjusted BUA and SOS than for children without ICS medication (BUA 15.00% vs. 5.41%; SOS 32.98% vs. 17.56%). However, we cannot differentiate possible negative effects of ICS from influences of the underlying inflammatory disease because higher asthma severity was associated with greater use of ICS medication. Additionally, the higher physical activity of children with less severe asthma can have influenced quantitative ultrasound (QUS) parameters positively, compared to patients with a higher degree of exercise-induced symptoms. For differentiation of possible negative effect of ICS on ultrasonic bone quality and for evaluation of the potentials of the method, further longitudinal QUS assessment of asthmatics receiving a new ICS treatment is needed.