Evaluating the effects of asthma therapy on childhood growth: what can be learnt from the published literature?

The difficulties of assessing the effects of asthma therapy on childhood growth were explored in the first part of this review. In this part of the review growth studies with inhaled corticosteroids were selected that included a control group, measured height by stadiometry and were of > or = 1 yr duration. The studies were classified as type 1 (placebo control), type 2 (nonsteroidal therapy control), type 3 (comparator inhaled corticosteroid control) or type 4 ("real-life" studies with dose adjustment). The design attributes of these studies were then compared with the recommendations described in the first part of this review. Of the 18 studies identified, 17 were susceptible to one or more important confounding factors. Nevertheless, the outcomes of all 18 studies were mostly consistent. At recommended doses, beclomethasone dipropionate and budesonide demonstrated a small degree of growth suppression over 1-2 yrs (study types 1 and 2), but there was little evidence of such an effect with fluticasone propionate. Studies comparing different inhaled corticosteroids at recommended doses indicated more rapid growth with fluticasone propionate than with beclomethasone dipropionate or budesonide. However, none of the inhaled corticosteroids appeared to affect final height. In conclusion, the results from the majority of published growth studies with inhaled corticosteroids must be interpreted with a degree of caution owing to their potential susceptibility to important confounding factors. Further well-designed studies are needed to establish whether different inhaled corticosteroids have different effects on growth in the long term.