Deteriorating diabetic control through adolescence-do the origins lie in childhood?

To determine whether intra-individual measures of diabetes control deteriorated through adolescence and whether HbA1c in late childhood was predictive of HbA1c after adolescence.

Retrospective analysis of sequential 3-6 monthly data including HbA1c, height, weight, and total daily insulin dosage in 118 patients with Type 1 diabetes aged between 8.00 and 17.99 years between 1983 and 1999.

In females mean body mass index (BMI) increased sharply during adolescence but there was no significant increase in males. The mean total daily dose of insulin/weight (TDDI/W) increased sharply for females through puberty. Males exhibited a constant rate of increase in mean TDDI/W from pre- to post-puberty. There was a constant increase in mean HbA1c for females, with an estimated increase from pre- to post-puberty of 0.92%. In males there was only a slight increase from pre- to peri-puberty and no change subsequently. Comparing pre-puberty (8-9.99 years) and post-puberty (15-17.99 years) in the total group, 47% of patients remained in the same mean HbA1c grouping, 37% had worsened control and 16% had improved control. Analysis of change in the absolute value of mean HbA1c showed that the majority of patients had mean HbA1c values that remained within +/- 1% (54%) or +/- 2% (82%) from pre- to post-puberty. A significant proportion showed significantly worsening control with only a minority showing improved metabolic control from pre- to post-puberty.

The likelihood of a significant improvement in HbA1c from late childhood to adolescence is remote, with the majority of patients having either constant or deteriorating metabolic control.