Effect of Glycemic Control on Growth Velocity in Children With IDDM

Abstract

Objective To determine the effect of glycemic control on growth velocity in children with insulin-dependent diabetes mellitus. Research Design and Methods One hundred twenty-two children with insulin-dependent diabetes mellitus were studied over a 5-yr period. Every 4 mo, glycemic control was assessed by measuring total glycosylated hemoglobin (GHb), pubertal status was determined by physical examination, and height was measured with a stadiometer. Height measurements were normalized for age and sex by converting them to Ζ scores (the number of SD above or below the mean for age and sex). Alterations in growth velocity were determined by the change in Ζ scores (ΔΖ) between visits (i.e., no change in tau score = normal growth velocity; decrease in Ζ score = growth deceleration; and increase in Ζ score = growth acceleration). Results A linear relationship was seen between GHb levels and the change in Ζ scores (r = −0.117, P = 0.001). GHb values < 8% were associated with growth acceleration (ΔΖ = +0.10 ± 0.03), and the greatest growth deceleration occurred when GHb was > 16% (ΔΖ =−-0.07 ± 0.03). The level of GHb at which growth suppression occurred (mean ΔΖ became negative) was dependent on pubertal status: Tanner stage 1 ≤ 10%, Tanner stages 2 and 3 ≤ 8%, Tanner stages 4 and 5 ≤ 16%. Conclusions Linear growth velocity in children with insulin-dependent diabetes mellitus is heavily related to metabolic control. Children who are prepubertal or in the early stages of puberty are the most vulnerable to growth suppression. Once puberty is well established, growth suppression does not occur until marked hyperglycemia (GHb > 16%) exists.