Catch-Up Growth: Testing the Hypothesis of Delayed Growth Plate Senescence in Humans

Theoretical catch-up growth curves predicted by the delayed senescence hypothesis. A, The delayed senescence hypothesis predicts that the height curve during catch-up growth (dashed line) should represent simple time-shift of normal (50 percentile, solid line) height curve. B, Therefore the delayed senescence hypothesis also predicts that, during catch-up growth, height should remain normal for a younger child (based on initial height age). Consequently, the height SDS for adjusted age should remain close to 0 (curve b). If the height SDS for adjusted age increases over time, this would indicate that the child's growth rate is rapid even for a younger child (curve a). Curve a would be inconsistent with the delayed senescence hypothesis.

Height SDS for chronological age (A) and for adjusted age (B and C) after institution of a gluten-free diet for celiac disease. A, Before initiation of the gluten-free diet, the average height SDS for chronological age (CA) was negative, indicating short stature. On the gluten-free diet, the height SDS increased, indicating catch-up growth (figure reprinted from reference 11 with permission of S. Karger AG, Basel). B, Age was adjusted for height age (HA) at diagnosis. C, Age was adjusted for bone age (BA) at diagnosis. The upper and lower curves in each panel represent 95% confidence interval of the mean. In both B and C the height SDS for adjusted age remained close to 0, indicating that growth was normal for a younger child.