Effects of Weight Reduction Therapy on Obstructive Sleep Apnea Syndrome and Arterial Stiffness in Patients with Obesity and Metabolic Syndrome

Abstract

Obesity and metabolic syndrome (MetS) and obstructive sleep apnea (OSA), which are often accompanied by obesity, are each independently associated with cardiovascular disease (CVD). However, the influence of OSA on arterial stiffness in obese patients remains unclear. We herein examined the relationships between the severity of OSA and CVD risk factors, including the severity of MetS and arterial stiffness, in obese patients. In addition, we evaluated the effects of weight reduction therapy on OSA and arterial stiffness. Among the 60 overweight or obese Japanese outpatients enrolled, 46 (76.7%) met the MetS criteria. The apnea-hypopnea index (AHI) and cardio-ankle vascular index (CAVI), a new index of arterial stiffness, were significantly higher in the MetS patients than in the non-MetS patients, whereas there were no significant differences in body mass index, blood pressure or the low-density lipoprotein cholesterol level. A multivariate regression analysis revealed that waist circumference, the C-reactive protein level and CAVI were independently correlated with AHI. In addition, age, SBP, IRI and AHI were independently correlated with CAVI. Furthermore, weight reduction therapy, including diet and exercise, over a three-month period significantly decreased the AHI and CAVI values in parallel with a reduction in BMI. This study demonstrated that the severity of OSA is significantly correlated with the severity of MetS and arterial stiffness in obese patients. Short-term weight reduction therapy improves not only metabolic dysfunction, but also the severity of OSA and arterial stiffness, as measured according to the CAVI. Such changes may help to prevent atherosclerosis in obese patients.