TY - JOUR T1 - “Syndrome Z”: the interaction of sleep apnoea, vascular risk factors and heart disease JF - Thorax JO - Thorax SP - S25 LP - S28 DO - 10.1136/thx.53.2008.S25 VL - 53 IS - suppl 3 AU - Ian Wilcox AU - Stephen G McNamara AU - Fiona L Collins AU - Ronald R Grunstein AU - Colin E Sullivan Y1 - 1998/10/01 UR - http://thorax.bmj.com/content/53/suppl_3/S25.abstract N2 - Obstructive sleep apnoea (OSA) has been linked to increased cardiovascular morbidity and mortality from both coronary heart disease and stroke,1-3 but whether this risk is due to coexistent known cardiovascular risk factors or specific effects of OSA remains to be established.In populations at risk of vascular disease, many patients who experience a cardiovascular event either do not have identifiable risk factors or have disease severity which appears to be out of proportion to their known risk factors. A lot of the variance in the incidence of vascular disease is therefore not explained by known risk factors. It is possible that OSA is a cardiovascular risk factor, previously largely unrecognised, which may account for some of the apparently unexplained variance in vascular risk.Data from the Framingham and other studies have clearly shown that at any level of systolic blood pressure there is a substantial increase in cardiovascular risk with increasing levels of plasma cholesterol, and the presence of glucose intolerance (insulin resistance) further increases this risk.4 Although obesity is a well recognised cardiovascular risk factor, the distribution of body fat is an independent risk factor with central or visceral obesity increasing cardiovascular risk. In the study by Larsen and co-workers5 increasing waist circumference (an index of central obesity) increased the risk of both coronary heart disease and stroke at all tertiles of body mass index.Since these risk factors have been shown to be independent predictors of adverse events, they will show at least additive effects in combination and possibly potentiate each other. Epidemiological and other studies have identified clustering of multiple vascular risk factors. One such cluster is a quartet of risk factors which includes systemic hypertension, insulin resistance, hyperlipidaemia, and central obesity which been defined as “syndrome X”.6 In this cluster there are … ER -