Glycaemic control and body mass index in late-adolescents and young adults with Type 1 diabetes mellitus: a population-based study

Aims Studies of children with diabetes up to the age of 15 years report deteriorating glycaemic control in the early teenage years. The aim was to investigate glycaemia and body mass index in older teenagers and young adults. Method A Scottish, regional, population-based, cross-sectional study of 255 young people (117 female, 138 male) with Type 1 diabetes, aged 15-25 years (mean +/- SD 19.8 +/- 2.8 years, diabetes duration: 8.8 +/- 5.4 years) registered on a diabetes database. Glycaemic control, body mass index (BMI) and insulin regimens were assessed in three age groups [group 1 (n = 96) 15-18 years; group 2 (n = 74) 18.1-22 years; and group 3 (n = 85) 22.1-25 years]. Results Subjects in the oldest age group had a significantly lower mean HbA(1c) than those in the youngest age group (8.8 +/- 1.7 vs. 9.9 +/- 1.9%; P < 0.001). Mean BMI was higher in group 3 (25.2 +/- 3.4 kg/m(2)) compared with group 1 (23.9 +/- 3.1 kg/m(2); P < 0.001). HbA(1c) levels were higher in the younger subjects and women. Lower HbA(1c) levels were associated with a higher BMI (r = -0.324, P < 0.001) in men only. Overall, 74% took three or more injections a day, of whom 60% were on basal/bolus therapy. The proportion on basal/bolus insulin therapy increased with age and duration of diabetes. Conclusion Compared with adolescents, young adults with Type 1 diabetes have better glycaemic control and higher BMI. This was associated with lower insulin requirements.