Drs. Giangiacomo and Gleason are quite correct in their criticism that the number of patients with vitamin D deficiency rickets is too small for statistical comparison of the concentration of serum 25-hydroxyvitamin D (25-OH-D) in mild, moderate, and severe rickets. For this reason, we did not attempt this type of statistical comparison (Student's t test). The statistical analysis which supports our conclusion is the calculation of the regression between senim 25-OH-D, ng/ml and the stage of the disease, designated by arbitrary numbers 1, 2, and 3 for mild, moderate, and severe.
