Eur Respir J 2009; 33:797-803 Copyright ©ERS Journals Ltd 2009 doi: 10.1183/09031936.00023208
Association between C-reactive protein and unrecognised sleep-disordered breathing in the elderly1 Service de Physiologie Clinique et de l'Exercice, CHU Nord, and 3 Faculté de Médecine Jacques Lisfranc, Université Jean Monnet, PRES de Lyon, Saint-Etienne, France, 2 Division of Primary Care Medicine, Dept of Community Medicine and Primary Care, University Hospitals, Geneva, Switzerland. CORRESPONDENCE: F. Roche, Service de Physiologie Clinique et de l'Exercice EFCR, CHU Nord - Niveau 6, F-42055 Saint-Etienne Cedex 2, France. Fax: 33 477828447. E-mail: Frederic.Roche{at}univ-st-etienne.fr Keywords: C-reactive protein, elderly, hypoxaemia, inflammation, sleep apnoea
Received: February 13, 2008
Elevated levels of C-reactive protein (CRP) have been reported in patients with sleep-disordered breathing (SDB) and may represent an inflammatory marker of cardiovascular risk. However, the association of CRP with SBD in presumed healthy elderly subjects is unknown.
In total, 851 (58.5% females) 68-yr-old subjects, who were free of any known cardiac or sleep disorders, were prospectively examined. Subjects underwent unattended polygraphy, and the apnoea/hypopnoea index (AHI) and oxyhaemoglobin desaturation index (ODI) were assessed. Elevated levels of CRP were found on the morning after the sleep study in patients with more severe SDB. A significant correlation was found between CRP levels, time spent at night with arterial oxygen saturation <90% and ODI. No association was found between CRP levels and AHI. After adjustments for body mass index, smoking status, hypertension, diabetes and dyslipidaemia, a significant association remained between CRP levels and ODI >10 events·h–1.
CRP levels were frequently increased in a large sample of elderly subjects free of major cardiovascular disease. CRP levels were not correlated with the AHI and the indices of sleep fragmentation; the ODI >10 events·h–1 was the strongest predictor of raised CRP level.
The present results suggest that, in the elderly, intermittent hypoxaemia may underlie inflammatory processes leading to cardiovascular morbidity.
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||