Pubertal growth, sexual maturation, and final height in children with IDDM. Effects of age at onset and metabolic control.

OBJECTIVE: To evaluate growth and pubertal development in children with IDDM and the influence of the age at onset of IDDM and the degree of metabolic control on final height.

RESEARCH DESIGN AND METHODS: We conducted a retrospective evaluation of 62 subjects followed longitudinally both clinically and metabolically from the onset of IDDM until final height was reached.

RESULTS: Height at diagnosis was within the normal percentiles in boys (0.5 +/- 1.0 standard deviation score [SDS]) and girls (0.4 +/- 1.0 SDS), but above the genetic target height (-1.0 +/- 0.9 SDS in boys and -1.1 +/- 0.6 SDS in girls; P = 0.0001 for both comparisons). Although a lesser height gain was observed during the ensuing years, the final height reached by boys (-0.4 +/- 1.1 SDS) and girls (-0.4 +/- 0.9 SDS) was higher than the genetic target height. Blunted total pubertal growth was observed both in boys (24.5 +/- 3.6 cm) and girls (20.1 +/- 4.2 cm). The decrease in height gain was independent of the duration of IDDM, the degree of metabolic control, or the insulin requirement. The greater the height at diagnosis, with respect to the genetic target height, the lesser was the subsequent height gain to reach final adult height (r = 0.34, p < 0.01). BMI increased with age as normally occurs in healthy children, independent of the duration of disease and the degree of metabolic control. Pubertal development began and progressed normally both in boys and girls. In boys, a testicular volume of 4 ml was reached at a mean age of 12.1 +/- 0.9 years. In girls, breast enlargement occurred at a mean age of 10.4 +/- 1.2 years and the mean age of menarche was 12.8 +/- 1.4 years. Pubertal development and progression occurred independent of the age at onset of IDDM, the glycemic control, or the insulin requirement during the pubertal period.

CONCLUSIONS: Children with IDDM have normal onset of puberty and normal sexual maturation. Even though final height falls within the normal percentiles, the diminished height gain after diagnosis requires further investigation.