Ventilatory functions of normal children and young adults: Mexican-American, white, and black. III. Sitting height as a predictor.

We studied the ventilatory functions of 1800 normal children ranging in age 7 to 20 years. Boys and girls of black, white, and Mexican-American ethnic groups were represented adequately. The FVC and FEV1 of normal black children were fully 1 SD lower than those of white children with the same standing height. Such racial differences could not be corrected by a scaling factor, because the differences vary with sex and also with height as the children grow. Using sitting height as a predictor greatly reduced the racial differences of ventilatory functions and permitted the application of one set of prediction equations for children of all three groups.