Effects of inhaled corticosteroid on bone turnover in children with bronchial asthma

Long-term usage of systemic steroids is associated with multiple side effects. One of the major morbidities is due to its effect on bone metabolism leading to bone loss and resulting in skeletal fractures. This study was conducted to determine the effects of inhaled steroids on bone mineral density (BMD) and biochemical bone markers. Twenty-four children with frequent episodic or mild persistent asthma who satisfied the clinical criteria for starting on inhaled corticosteroids (ICS) were enrolled into the study. The BMD scan was done using dual energy X-ray absorptiometry, prior to starting ICS therapy and 6 months later. Biochemical markers of bone metabolism, (i) serum osteocalcin as a bone formation marker, and (ii) urinary deoxypyridinoline (Upd) as a bone resorption marker, were taken prior to ICS treatment and at 2 monthly intervals. The biochemical markers were all taken in the morning. Twenty-four, age- and sex-matched children with mild episodic asthma, not requiring ICS, were used as controls for the BMD measurements. The BMD scan was done upon enrollment into the study and 6 months later. Twenty-four children on ICS and 24 controls completed the study. The subjects were on a mean dose of beclomethasone dipropionate (BDP) 0.4 mg/day. One subject needed a short course of Prednisolone in the early treatment period. None of the controls needed oral steroid therapy. One child in the control group sustained a greenstick fracture after an accidental fall. The mean rate of change of BMD was 1.8% +/- 12.3 in the subjects on BDP. This was lower than the 6.1% +/- 10.6 among the control subjects. However, this difference did not reach statistical significance (P = 0.16). There was a significant increase in serum osteocalcin level after 6 months of BDP treatment from 66.83 +/- 22.71 ng/mL to 81.61 +/- 24.66 ng/mL (P < 0.005). There was a decline in Upd from 36.2 +/- 47.1 nmol/mmol creatinine to 21.4 +/- 6.92 nmol/mmol creatinine. However, this did not reach statistical significance. There was no difference in the statural gain between the subjects on ICS and their controls. This study showed that 6 months of ICS therapy (mean dose 0.4 mg/day) had no significant adverse effect on bone metabolism in asthmatic children.