The natural history of somatosensory and autonomic nerve dysfunction in relation to glycaemic control during the first 5 years after diagnosis of Type 1 (insulin-dependent) diabetes mellitus

Abstract
The natural evolution of neural dysfunction was studied prospectively over 5 years following diagnosis of Type 1 (insulin-dependent) diabetes in 32 patients aged 12–36 years. Motor and sensory nerve conduction velocities, heart rate variation at rest and during deep breathing, and pupillary function were measured at diagnosis and after 3,12, 24,48, and 60 months. Thermal and vibration sensation thresholds were determined after 24, 48, and 60 months of diabetes. Mean HbA1 levels of months 3–60 within the normal range of 1 of months 3–60≥8.3% (10.0±0.3%) was found in 19 patients (Group 2). Mean nerve conduction was significantly diminished in Group 2 as compared with Group 1 in at least 4 out of 6 nerves tested during months 12–60 (ppppp<0.05). These findings suggest that the evolution of subclinical and symptomatic neuropathy during the first 5 years after diagnosis of Type 1 diabetes may be predicted by poor glycaemic control and prevented by near-normoglycaemia.