IntroductionThere is little information on the gastrointestinal motility abnormalities and autonomic neuropathy of children with gastrointestinal symptoms and type 1 diabetes mellitus (T1DM).MethodsThe authors studied 33 consecutive patients (mean age, 15.3 years; 13 males) with T1DM (median duration, 7.7 years) attending the outpatient clinic because of chronic dyspepsia (CD; n = 14), or chronic constipation (CC; n = 19), and 48 consecutive non‐T1DM patients (mean age, 13.7 years; 18 males), who presented with similar symptoms (18 with CD; 30 with CC). Fasting serum motilin concentrations and cardiovascular autonomic function tests (CAFT) were assessed and compared with those of age‐ and gender‐matched healthy control subjects. Gastric emptying half time (GE t1/2) of a solid meal and mouth‐to‐anus transit time (MATT) were measured in patients with CD and CC, respectively.ResultsCAFT was comparable between patients with T1DM and healthy control subjects. GE t1/2 and MATT were not different between T1DM patients and non‐T1DM patients with CD and CC, respectively. However, a marginally significant positive correlation was found in the patients with T1DM between GE t1/2 and blood glucose concentrations (R = 0.54; P = 0.08). In addition, serum motilin concentrations were significantly lower in patients with T1DM compared with healthy control subjects (P < 0.0005), and in patients with T1DM and higher serum glucose concentrations compared with those with lower serum glucose concentrations (P = 0.03).ConclusionAutonomic neuropathy is not an etiological factor of gastrointestinal symptoms in children and adolescents with diabetes. Mild or moderate hyperglycemia does not affect gastrointestinal motility.