(my emphasis) Establishing this cause and effect relationship is what Yaggi did in the study published in the Nov. 10 issue of The New England Journal of Medicine.Henry Yaggi and Vahid Mohsenin in Lancet Neurology 2004; 3:333-342 wrote:
DOI:10.1016/S1474-4422(04)00766-5
Obstructive sleep apnoea and stroke
Henry Yaggi and Vahid Mohsenin
Summary
Many patients with stroke have concomitant sleep apnoea, which can affect recovery potential. Although stroke can lead to the development of sleep-disordered breathing, the current evidence suggests that sleep-disordered breathing may function as a risk factor for stroke. In this review, we focus on the association between obstructive sleep apnoea and stroke reviewing both the epidemiological data with respect to causation and the biological data, which explores pathogenesis. There is convincing evidence to believe that sleep apnoea is a modifiable risk factor for stroke; however, prospective studies are needed to establish the cause-and-effect relationship.
My empahsis. Marin's study was referenced by Yaggi in the aforementioned 2005 NEJM, and that's how I found it.Jose M Marin , Santiago J Carrizo , Eugenio Vicente and Alvar GN Agusti in The Lancet 2005; 365:1046-1053 wrote:
DOI:10.1016/S0140-6736(05)71141-7
Long-term cardiovascular outcomes in men with obstructive sleep apnoea-hypopnoea with or without treatment with continuous positive airway pressure: an observational study
Summary
Background
The effect of obstructive sleep apnoea-hypopnoea as a cardiovascular risk factor and the potential protective effect of its treatment with continuous positive airway pressure (CPAP) is unclear. We did an observational study to compare incidence of fatal and non-fatal cardiovascular events in simple snorers, patients with untreated obstructive sleep apnoea-hypopnoea, patients treated with CPAP, and healthy men recruited from the general population.
Methods
We recruited men with obstructive sleep apnoea-hypopnoea or simple snorers from a sleep clinic, and a population-based sample of healthy men, matched for age and body-mass index with the patients with untreated severe obstructive sleep apnoea-hypopnoea. The presence and severity of the disorder was determined with full polysomnography, and the apnoea-hypopnoea index (AHI) was calculated as the average number of apnoeas and hypopnoeas per hour of sleep. Participants were followed-up at least once per year for a mean of 10·1 years (SD 1·6) and CPAP compliance was checked with the built-in meter. Endpoints were fatal cardiovascular events (death from myocardial infarction or stroke) and non-fatal cardiovascular events (non-fatal myocardial infarction, non-fatal stroke, coronary artery bypass surgery, and percutaneous transluminal coronary angiography).
Findings
264 healthy men, 377 simple snorers, 403 with untreated mild-moderate obstructive sleep apnoea-hypopnoea, 235 with untreated severe disease, and 372 with the disease and treated with CPAP were included in the analysis. Patients with untreated severe disease had a higher incidence of fatal cardiovascular events (1·06 per 100 person-years) and non-fatal cardiovascular events (2·13 per 100 person-years) than did untreated patients with mild-moderate disease (0·55, p=0·02 and 0·89, p<0·0001), simple snorers (0·34, p=0·0006 and 0·58, p<0·0001), patients treated with CPAP (0·35, p=0·0008 and 0·64, p<0·0001), and healthy participants (0·3, p=0·0012 and 0·45, p<0·0001). Multivariate analysis, adjusted for potential confounders, showed that untreated severe obstructive sleep apnoea-hypopnoea significantly increased the risk of fatal (odds ratio 2·87, 95%CI 1·17–7·51) and non-fatal (3·17, 1·12–7·51) cardiovascular events compared with healthy participants.
Interpretation
In men, severe obstructive sleep apnoea-hypopnoea significantly increases the risk of fatal and non-fatal cardiovascular events. CPAP treatment reduces this risk.
http://www.thelancet.co.uk - anyone can register to read the abstracts.
O.
