Impact of obstructive sleep apnoea on diabetes and cardiovascular disease
Patients with obstructive sleep apnoea (OSA) have a high prevalence of insulin resistance (IR), type 2 diabetes mellitus and cardiovascular disease (CVD), indicating a strong association among the conditions. Intermittent hypoxia with fragmentation of normal sleep contributes to significant autonomic dysfunction plus proinflammatory and procoagulopathy states,1 leading to IR and CVD (Box 1). Although obesity is a common risk factor for OSA, IR and particularly CVD, current evidence suggests that OSA itself is an independent risk factor for both IR and CVD. Clinical data suggest that this effect is most likely mediated via intermittent oxygen desaturation. However, teasing out the precise role that OSA plays in IR and CVD, independent of obesity, is difficult given the confounding effects of inactivity, sleep deprivation, diet and OSA variability in terms of age of onset, duration and severity. With this in mind, this paper attempts to review the epidemiological and interventional evidence connecting OSA with IR and CVD (Box 2).