Bone mineral density in subjects with mild asthma randomised to treatment with inhaled corticosteroids or non-corticosteroid treatment for two years

Background-Inhaled corticosteroids are clearly beneficial for patients with asthma of moderate severity, but the risks and benefits of using them in p atients with milder asthma are less clear. We have compared the change in b one mineral density over 2 years in adults with mild asthma randomised to r eceive an inhaled corticosteroid or non-corticosteroid treatment. Methods-Subjects with mild asthma (mean forced expiratory volume in one sec ond (FEV1) 86% predicted, mean age 35 years, taking beta agonists only) wer e randomised to receive inhaled budesonide, inhaled beclomethasone dipropio nate, or non-corticosteroid treatment for 2 years in a prospective randomis ed open study in 19 centres in France, New Zealand, Spain, and the UK. The corticosteroid dose was adjusted according to a written selfmanagement plan . The main outcome measure-change in bone mineral density after 6, 12, and 24 months-was measured "blind". Secondary outcomes included lung function, the relation between change in bone density and inhaled steroid dose and ch ange in biochemical markers of bone metabolism. Results-Of 374 subjects randomised, 239 (64%) completed the study and were included in the analysis. The median daily doses of inhaled budesonide (n=8 7) and beclomethasone (n=74) were 389 mug and 499 mug, respectively. Subjec ts treated with an inhaled corticosteroid had better asthma control than th ose in the reference group (n=78). Change in bone mineral density did not d iffer between the three groups over the 2 years, nor did it correlate with changes in markers of bone metabolism. The mean change in bone mineral dens ity over 2 years in the budesonide, beclomethasone dipropionate, and refere nce groups was 0.1%, -0.4%, and 0.4% for the lumbar spine and -0.9%, -0.9%, and -0.4% for neck of the femur. Mean daily dose of inhaled steroid was re lated to reduction in bone mineral density at the lumbar spine but not at t he femoral neck. Conclusion-In subjects with mild asthma an inhaled corticosteroid provided better asthma control than alternative non-corticosteroid treatment with no difference in change in bone mineral density over 2 years. The relation be tween dose of inhaled corticosteroid and change in bone density at the lumb ar spine may be due to a direct effect of inhaled corticosteroids on bone. Since inhaled steroid dose is also related inversely to lung function, an e ffect of asthma severity on bone density was also possible.