1 British Columbia Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
In Reply.
In view of Dr Kauffmann's suggestion, we reanalyzed our data to find whether the FEF25%-75%/FVC ratio revealed the same sex and age differences as did the FEF25%-75% percent predicted when it was used to assess the severity of asthma. The results were the same. When comparing children of nonsmoking and smoking mothers, the mean FEF25%-75%/FVC ratios were 0.81 vs 0.69 (P = .009) for boys and 0.89 vs 0.83 (P = .54) for girls.