Sleep apnoea syndrome and 10‐year cardiovascular risk in females with type 2 diabetes: relationship with insulin secretion and insulin resistance

BACKGROUND: Obstructive sleep apnoea syndrome (OSAS) is a risk factor for type 2 diabetes mellitus (T2DM) and promotes cardiovascular events, especially in men. The prevalence of sleep apnoea and its association with microvascular and macrovascular diseases and glycaemic control are poorly documented in T2DM women. METHODS: A total of 305 T2DM women were sleep apnoea diagnosed through (hetero)anamnesis, Epworth's score, oximetry and polysomnography. Sleep apnoea[+] (n = 25) were compared with sleep apnoea[-] (n = 280) regarding cardiovascular risk factors, glucose homeostasis, micro/macrovascular complications and the United Kingdom Prospective Diabetes Study (UKPDS) 10-year risk. RESULTS: Mean (1 SD) age was 66 (12) years, diabetes duration 15 (9) years, sleep apnoea prevalence 8.2% and metabolic syndrome 86%. There were no differences in age, diabetes duration, education, smoking and blood pressure between groups. Sleep apnoea[+] had significantly higher values of body mass index, waist, relative/absolute fat, conicity, visceral fat (all p < 0.0001) and lower skeletal muscle (p = 0.0008). The sleep apnoea[+] group was more insulin resistant [homeostasis model assessment (HOMA S): 37 (20)% versus 59 (44)%; p < 0.0001] and had lesser residual insulin secretion (HOMA B × S: 20 (12)% versus 30 (19)%; p = 0.0006), increased hyperbolic product loss (p = 0.0442) and poorer glycaemic control (HbA1c 69 (12) versus 62 (13) mmol mol(-1) ; p = 0.0099). All atherogenic dyslipidaemia components and inflammatory markers were worsened in sleep apnoea[+]. Women with sleep apnoea had higher UKPDS risk of CAD: 18 (11)% versus 12 (10)% (p = 0.0136). Prevalent micro/macrovascular complications were not different between groups. CONCLUSIONS: Sleep apnoea, a frequent comorbidity of T2DM women, is associated with central fat, atherogenic dyslipidaemia, inflammation, worsening β-cell function, poorer glycaemic control and coronary artery disease risk. Sleep apnoea may increase residual vascular risk for microvascular and macrovascular events in T2DM women.