Introduction Rapid weight gain is often observed following initiation of insulin therapy in children with type 1 diabetes mellitus (T1DM) and girls are particularly at risk of becoming overweight. The authors evaluated body composition changes in children during the first year after diagnosis and related this to markers of cardiovascular risk.

Methods Body mass index (BMI) and body composition measured by whole body dual energy x-ray absorptiometry (DEXA) were assessed in 30 patients (18 boys) with T1DM 3–10 days after diagnosis, 6 weeks later and at 1 year, and on two occasions 1 year apart in 14 controls (8 boys). Cardiovascular risk markers were assessed in T1DM subjects at 1 year.

Results T1DM subjects had lower BMI SD scores (SDS) at diagnosis than controls (mean (SD) BMI SDS −0.67 (1.34) vs 0.20 (1.14), p<0.05) and reduced percentage body fat (20.3% (4.6) vs 24.5% (7.7), p<0.05). T1DM subjects normalised their body composition at 6 weeks and this was maintained 1 year later. Girls with diabetes were thinner than boys at diagnosis (BMI SDS −1.64 (1.02) vs −0.02 (1.17), p<0.05) and at 1 year (BMI SDS −0.58(0.9) vs 0.65 (0.98), p<0.05). Girls had higher glycated haemoglobin (HbA1c) (8.8% (1.2) vs 7.8% (1.0), p<0.05), insulin dose (1.01 (0.30) vs 0.82 (0.18) U/kg/day, p=0.04), total cholesterol (4.30 (0.45) vs 3.79 (0.50) mmol/l, p<0.05) and high-density lipoprotein (2.62 (0.53) vs 2.02 (0.37) mmol/l). High sensitivity C reactive protein and fibrinogen were in the normal range and there were no differences between genders.

Discussion Insulin deficiency at diagnosis of diabetes causes a catabolic state that is predominantly lipolytic. Body composition normalises within 6 weeks of treatment, though girls remain thinner than boys both at diagnosis and 1 year thereafter, in contrast to published findings. Despite girls being prescribed a larger insulin dose, their HbA1c and cholesterol levels are higher at 1 year suggesting increased insulin resistance and cardiovascular risk.