Knemometry, urine cortisol excretion, and measures of the insulin-like growth factor axis and collagen turnover in children treated with inhaled glucocorticosteroids

Correlations between knemometric (lower leg length) growth rates and urine free cortisol excretion, respectively, and serum concentrations of IGF-I, IGF binding protein-3, osteocalcin, carboxy terminal propeptide of type I collagen (PICP), carboxy terminal pryridinoline cross-linked telopeptide of type I procollagen (ICTP), and amino terminal propeptide of type III procollagen (PIIINP) were investigated in 17 asthmatic children aged 7-14 y during treatment with fluticasone propionate, 200 mu g, and beclomethasone dipropionate, 400 and 800 mu g/d, taken from dry powder inhalers. The study was a double blind, crossover trial with three active treatment periods and two wash-out periods. All periods were 15 d long. Overnight urine free cortisol/ creatinine x 10(6) did not correlate with knemometric growth rates or any of the serum markers. Significant correlations (Pearson's correlation coefficient, P) between knemometric growth rates and IGF-I (0.41; 0.006), IGFBP-3 (0.35; 0.02), PICP (0.44; 0.003), ICTP (0.35; 0.001), and PIIINP (0.46; 0.002) were found. Compared with fluticasone propionate, 200 mu g, beclomethasone dipropionate, 400 and 800 mu g, caused significant suppression of lower leg growth rate (F = 12.41; p = 0.002, and F = 23.30; p = 0.0001, respectively) and of urine free cortisol/creatinine X 10(6) (F = 10.52; p = 0.003, and F = 13.74; p = 0.001) Beclomethasone, 800 mu g, caused suppression of PICP compared with fluticasone propionate, 200 mu g (F = 8.31; p = 0.008), and beclomethasone, 400 mu g (F = 7.53; p = 0.01). Both low (F = 6.82; p = 0.02) and high (F = 23.35; p = 0.0001) doses of beclomethasone were associated with reduced concentrations of ICTP, the high dose being the most suppressive (F = 4.42; p = 0.05). Beclomethasone 400 (F = 9.75; p = 0.004) and 800 mu g (F = 23.61; p = 0.0001) resulted in reduced levels of PIIINP. Reduced short-term knemometric growth rates in children treated with inhaled glucocorticosteroids reflect suppressive effects on type I and type III collagen turnover.