Differences in lung function and chest dimensions in school-age girls and boys

The present analysis was undertaken to find out whether differences in the performance of the lungs of boys and girls of the same height are explicable by differences in thoracic size. We measured forced vital capacity (FVC), peak expiratory flow (PEF) and forced expiratory flows (FEFs), when 50% and 75% of FVC had been exhaled (FEF50, FEF75), and standing height, chest width and depth and biacromial diameter in 1187 schoolchildren aged 6-18 years. Thoracic dimensions were usually greater in boys than in girls of the same height, except for the height range of 150.0-164.9 cm. For this height range, the pulmonary function variables (PEF, FEF50, FEF75 and PEF/FVC) were significantly higher in girls, and for FVC almost as high as the male values. For FEF50/FVC and FEF75/FVC, the female values were larger over the whole height range (115.0-184.9 cm), but even for these parameters the differences were greatest for the height range 150.0-164.9 cm. In conclusion, very similar growth patterns of lung function and thoracic parameters can suggest that differences in the lung function parameters of boys and girls of the same height may be explained by differences in the thorax size.