Increased prevalence of fetal haemoglobin in type 1 (insulin-dependent) diabetes mellitus.

Fetal haemoglobin levels were measured in 106 patients with Type 1 (insulin-dependent) diabetes mellitus during a period of two to three years. In 15 patients (14.1%) increased fetal haemoglobin levels (greater than 0.5%), determined by high pressure liquid chromatography, were found in contrast to 3% in a healthy control group (n: 100) of equal age distribution. In children aged over 6 years, elevated fetal haemoglobin levels were measured in 13 diabetic patients (13.3%) in contrast to none of the control group. There was no correlation between fetal haemoglobin levels and duration of diabetes, diabetic control (glycated haemoglobin) and dosage of insulin (U.kg-1, day-1). The 15 patients had a younger mean age at onset of diabetes (5.6 years) than a sex and age matched control group of diabetic patients without increased fetal haemoglobin levels (7.4 years, p less than 0.05). Longitudinal assessment revealed a significant decline of fetal haemoglobin levels with age (p less than 0.005) but a further increase in fetal haemoglobin levels were found in adolescent patients (n: 2). These data indicate a possible effect of insulin-treatment on delaying transition from fetal to adult haemoglobin synthesis or on reactivation of fetal haemoglobin production.