Objective: We studied retrospectively the statural growth and bone maturation of 32 children with primary hypothyroidism in order to relate their final heights to their chronological ages, height deficits and bone ages at the beginning of treatment. Patients were grouped according to age when treatment was started: Group 1 (G1) (n = 17): (15 girls, 1 boy) 3.09 +/- 0.8 yr; Group 2 (G2) (n = 9): (7 girls, 2 boys) 9.1 +/- 1.2 yr, and Group 3 (G3) (n = 6): (5 girls, 1 boy) 13.58 +/- 1.13 yr. At diagnosis G1 and G2 were prepubertal and G3 children were in puberty. In 10 patients of G1, 7 of G2 and 6 (all) of G3 final height was compared with target height.
Results: (SDS) Initial height: G1: -3.74 +/- 1.2; G2: -3.94 +/- 1.32; G3 -3.65 +/- 1. Height at onset of puberty: G1: -1.06 +/- 1.1; G2: -2.5 +/- 1.4. Height menarche stage 5: G1: -0.63 +/- 1.1; G2: -1.76 +/- 1.2; G3: -2.6 +/- 1.7. Final height: (whole group) G1: -0.85 +/- 0.91; G2: -1.6 +/- 1.3; G3: -2 +/- 1.5. Final height G1 (n = 10): -1.05 +/- 0.89; G2 (n = 7) 1.2 +/- 1. Target height G1 (n = 10): -1.22 +/- 0.78; G2 (n = 7): -0.8 +/- 1.2; G3 (n = 6): -1.07 +/- 1.5. Initial bone age: G1: -4.9 +/- 0.85; G2: -7.2 +/- 2.6; G3: -4.5 +/- 1.9. Bone age (onset of puberty) G1: -0.26 +/- 1.74; G2: -2 +/- 1.7; Bone age (menarche) G1: 0.09 +/- 0.6; G2: -0.5 +/- 0.6; G3: -0.76 +/- 0.82.
Conclusion: G1 and G2, prepubertal at diagnosis, reached a normal adult height with respect to target height; G3 did not, the difference being statistically significant (p < 0.04). Puberty plays a decisive role in the incomplete catch-up growth of longstanding hypothyroid patients.