NOCTURNAL HYPOGLYCEMIA AND SLEEP DISTURBANCES IN YOUNG TEENAGERS WITHINSULIN-DEPENDENT DIABETES-MELLITUS

Objective-To determine the effect of nocturnal hypoglycaemia on sleep architecture in adolescents with insulin dependent diabetes mellitus ( IDDM). Design-20 adolescents with IDDM (mean age 12.8 years, mean glyc ated haemoglobin (HbA(1c)) 8.9%) were studied on one night. Plasma glu cose was measured every 30 minutes and cortisol and growth hormone lev els every 60 minutes. Sleep was recorded using standard polysomnograph ic montages, and sleep architecture was analysed for total sleep time, stages 1-4, rapid eye movement, fragmentation, and arousals. Results- Six subjects (30%) became hypoglycaemic (five subjects < 2.5 mmol/l), with one being symptomatic. There were no differences in age, HbA(1c), duration of diabetes, or insulin regimen between hypoglycaemic and no n-hypoglycaemic subjects. Hypoglycaemia was not predicted by glucose m easurements before bed. There was no detectable rise in plasma cortiso l or growth hormone concentrations during hypoglycaemia. Sleep archite cture was not disturbed by nocturnal hypoglycaemia with no differences found in sleep stages, fragmentation, or arousals. Conclusions-Noctur nal hypoglycaemia is a common and usually asymptomatic complication of treatment in adolescents with IDDM. Moderate hypoglycaemia has not be en shown to affect sleep architecture adversely. These findings are co nsistent with, and may explain, the observation that severe hypoglycae mia, with consequent seizure activity, is more common at night than du ring the day. Counter-regulatory hormone responses to nocturnal hypogl ycaemia may be less marked than with similar degrees of diurnal hypogl ycaemia.