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This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 93/7/880    most recent expphysiol.2007.041277v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Aittokallio, J. Articles by Aittokallio, T. PubMed PubMed Citation Articles by Aittokallio, J. Articles by Aittokallio, T. Related Collections Respiratory

¹ Sleep Research Unit, Department of Physiology³ Biomathematics Research Group, Department of Mathematics, University of Turku, Finland Departments of ² Pulmonary Diseases⁴ Clinical Physiology and Nuclear Medicine, Tampere University Hospital, Tampere, Finland Departments of ⁵ Clinical Physiology and Nuclear Medicine⁶ Pulmonary Diseases, Turku University Central Hospital, Turku, Finland ⁷ Systems Biology Unit, Institut Pasteur, Paris, France

While there are a number of studies demonstrating association between arterial oxyhaemoglobin saturation events during sleep and markers of vascular impairment, the contribution of peripheral carbon dioxide to the development of atherosclerosis is poorly understood. We used ultrasound imaging to measure carotid artery intima–media thickness (IMT), as well as flow-mediated dilatation (FMD) and nitroglycerin-mediated dilatation (NMD) of brachial artery, in 103 generally healthy 46-year-old (±2 years) women. Characteristic event patterns were extracted from their overnight recordings of arterial oxyhaemoglobin saturation , end-tidal partial pressure of carbon dioxide and transcutaneous partial pressure of carbon dioxide . Importance of the event patterns was evaluated through predictive modelling of classes of the ultrasound measurements while controlling for potential confounders. Prediction accuracy was assessed with cross-validation and reported as the area under the receiver operating characteristic curve (AUC). Overnight patterns predicted each of the ultrasound measurements with high accuracy (IMT, AUC = 0.70; FMD, AUC = 0.75; and NMD, AUC = 0.81; all with P < 0.001). Adding the or patterns into the models did not significantly increase their predictive powers (AUC = 0.72, AUC = 0.77 and AUC = 0.83, respectively). The most important patterns reflected overnight variability in . These results suggest a novel link between overnight carbon dioxide events and early signs of vascular impairment in middle-aged women. Non-invasive measurements combined with non-linear modelling techniques could be used to reveal potential markers of vascular impairment present in relatively healthy subjects.

(Received 9 November 2007; accepted after revision 18 February 2008; first published online 22 February 2008)
Corresponding author J. Aittokallio: Sleep Research Unit, University of Turku, Dentalia, Lemminkäisenkatu 2, FI-20520 Turku, Finland. Email: jemato{at}utu.fi