Sleep in monozygotic twin pairs discordant for obesity. Kronholm, E, Aunola S, Hyypp[umlaut]a Mt, Kaitsaari M, Koskenvuo M, Mattlar C E, R[diaeresis]onnemaa T. Research and Development, Social Insurance Institution, FIN-20720 Turku, Finland, Department of Public Health, University of Turku, Department of Medicine, University of Turku
APStracts 2:0366A, 1995.
Nocturnal motor, breathing, and cardiac activity was recorded by using the static charge sensitive bed (SCSB) and sleep habits were studied by questionnaire in 24 pairs of monozygotic (MZ) twins discordant for their body mass index (BMI); the mean intra-pair difference between co-twins was 6.7 kg/m2. Intra-pair differences in sleep characteristics between co-twins were related to intra-pair differences in physiological and anthropometric characteristics. Two questions were tested. First, do MZ twins discordant for BMI differ in sleep behavior? Second, if they do, are differences in sleep associated with non-genetic differences in the body weight and metabolism or with other environmental factors? Obese twins had higher nocturnal motor activity levels, less 'quiet sleep' and more habitual snoring than their non-obese co-twins. Differences in sleep were associated with obesity-related factors. However, habitual snoring did not explain other intra-pair differences in sleep. It was concluded, that relatively moderate obesity is associated with disruption of physiological structure of sleep as measured by the Static Charge Sensitive Bed method and this disruption seems not to be associated with snoring or breathing disturbances.

Received 9 January 1995; accepted in final form 9 August 1995.
APS Manuscript Number A24-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 24 August 1995.