THE ADOLESCENT GROWTH SPURT IN CHILDREN WITH CYSTIC-FIBROSIS

The adolescent spurt in 230 children with cystic fibrosis (CF) treated at the Cleveland CF centre in northeastern Ohio was compared to that found in normal children from the Fels Longitudinal Growth Study in so uthwestern Ohio. The Preece-Baines Model 1 (PB1) growth equation was a pplied to longitudinal height data from both samples to describe a lar ge number of data points for each child in terms of a few biologically meaningful parameters, such as age, height, and velocity at the take- off and peak of the adolescent growth spurt. The growth spurt is delay ed by an average of 0-8 years and is about 1 cm/year slower at its pea k in CF patients compared to the normal controls. This delay should be considered when comparing clinical growth measurements of adolescent CF patients with normal standards. Peak velocity is lower than expecte d, even for late-maturing normal children, and height at take-off, pea k velocity, and adulthood is significantly reduced, especially in boys . These findings are consistent with the clinical impression that the growth spurt is delayed and attenuated in CF patients, particularly th ose with poor pulmonary function. Girls homozygous for the Delta F-508 mutation have significantly more growth retardation than those with o ther CF mutations.