It is now well established that obstructive sleep apnoea (OSA) is associated with an increased risk for cardiovascular disease, and that this is probably related to the fact that patients with sleep apnoea are likely to have a high prevalence of the risk factors that comprise the metabolic syndrome—namely, central adiposity, dyslipidaemia (low HDL cholesterol, raised triglycerides), high blood pressure, insulin resistance, and hyperglycaemia—even after correction for adiposity.^1–3 Type 2 diabetes is also typically associated with a similar metabolic profile, so it is not surprising that the prevalence of diabetes in obese hypertensive patients with sleep apnoea may be as high as 40%.⁴ Given that both type 2 diabetes and OSA are highly prevalent in the general population, it is important to establish the prevalence of OSA in people with type 2 diabetes as this may represent a significant population with undiagnosed sleep apnoea that may be amenable to treatment.

In this issue of Thorax West and colleagues⁵ have attempted to establish the prevalence of OSA in a community and hospital based population of men with established type 2 diabetes. Initial screening was by questionnaire to over 1600 men with diabetes, which achieved an overall response rate of 56%; this identified populations of “high risk” and “low risk” subjects based on self-reported height, weight, and sleep related …