SUMMARY

Aims  To evaluate serum levels of vascular endothelial growth factor (VEGF) in a large group of children, adolescents and young adults with Type 1 diabetes mellitus to investigate whether increased VEGF concentrations are associated with long‐term glycaemic control and microvascular complications.

Methods  The study involved 196 patients with Type 1 diabetes mellitus (age range 2–24 years, onset of diabetes before the age of 12 years, duration of disease longer than 2 years), without clinical and laboratory signs of microvascular complications; they were divided into three groups (group 1 –n = 37, age < 6 years; group 2 –n = 71, age 6–12 years; group 3 –n = 88–age > 12 years). Fifty‐three adolescents and young adults (age 16.1–29.7) with different grades of diabetic retinopathy and microalbuminuria were also selected (group 4). A total of 223 healthy controls were matched for age and sex with each group of patients with diabetes mellitus.

Results  VEGF serum levels were significantly increased in pre‐school and pre‐pubertal children with diabetes as well as in pubertal patients compared to controls. VEGF concentrations were markedly increased in adolescents and young adults with microvascular complications compared with both healthy controls and diabetic patients without retinopathy or nephropathy. Multivariate analysis showed that elevation of VEGF in serum was an independent correlate of complications. One‐year mean HbA_1c values were significantly correlated with VEGF concentrations (r = 0.372; P < 0.01). Children with HbA_1c levels greater than 10% had significantly higher VEGF concentrations when compared with matched patients whose HbA_lc levels were lower than 10%. In poorly controlled diabetic children (HbA_1c > 10%), long‐term (2 years) improvement of glycaemic control (aiming at HbA_1c < 7%) resulted in a significant reduction of VEGF levels.

Conclusions  VEGF serum concentrations are increased in prepubertal and pubertal children with diabetes. Glycaemic control influences VEGF serum levels. Severity of microvascular complications is associated with marked increase of VEGF concentrations in the serum of these patients.