OBJECTIVE To examine the growth of children before the onset of diabetes.

RESEARCH DESIGN AND METHODS Heights before diagnosis, expressed as SDS, of each diabetic child identified from the diabetes register and of two age- and sex-matched control subjects were obtained from records of routine examinations performed at 3.5, 6, 11, and 13 yr. The heights of their siblings, with control subjects, also were obtained.

RESULTS Diabetic children were considerably taller than control subjects before diagnosis (0–1 yr before diagnosis SDS 0.82 ± 0.26 vs. 0.16 ± 0.14, P < 0.05, n = 24; 1–2 yr before diagnosis SDS 1.02 ± 0.17 vs. 0.16 ± 0.14, P < 0.001, n = 30; 2–3 yr before diagnosis SDS 0.97 ± 0.23 vs. 0.04 ± 0.20, P < 0.005, n = 16). At more than 3 yr before diagnosis, the diabetic children were not significantly taller than control subjects (SDS 0.8 ± 0.2 vs. 0.27 ± 0.13, respectively; n = 33). The siblings of the diabetic children were no taller than control subjects.

CONCLUSIONS Diabetic children, but not their siblings, were taller than control subjects before diagnosis, suggesting growth-inducing metabolic changes may precede the onset of clinical diabetes by at least 3 yr.