Although continuous positive airway pressure (CPAP) is the first-line treatment for obstructive sleep apnea (OSA), its cardiometabolic benefits are questionable. Our aim was to explore whether the combination of a weight-loss Mediterranean diet/lifestyle intervention with OSA standard care leads to greater cardiometabolic improvements compared with standard care alone. We randomly assigned 187 adult, overweight, polysomnography-diagnosed moderate-to-severe OSA patients to a standard care group (SCG, n = 65), a Mediterranean diet group (MDG, n = 62) or a Mediterranean lifestyle group (MLG, n = 60). All three groups were prescribed with CPAP. Additionally, the SCG only received brief written healthy lifestyle advice, while intervention arms were subjected to a six-month weight-loss behavioral intervention based on the Mediterranean diet. The MLG also received guidance for improving physical activity and sleep habits. Glucose metabolism indices, blood lipids, liver enzymes and blood pressure improved only in intervention arms, and were significantly lower compared to the SCG post-intervention (all p < 0.05). The age-, sex-, baseline- and CPAP use-adjusted relative risk (95% confidence interval) of metabolic syndrome was 0.58 (0.34-0.99) for the MDG and 0.30 (0.17-0.52) for the MLG compared to the SCG. The MLG additionally presented a lower relative risk of metabolic syndrome compared to the MDG (0.52 (0.30-0.89)). After further adjustment for body-weight change, a lower relative risk of metabolic syndrome was still evident for the MLG compared to the SCG. In conclusion, although standard care alone does not improve OSA patients' cardiometabolic profile, its combination with a weight-loss Mediterranean diet/lifestyle intervention leads to significant cardiometabolic benefits.
Keywords: Mediterranean diet; Mediterranean lifestyle; cardiometabolic profile; dietary/lifestyle intervention; metabolic syndrome; obstructive sleep apnea; weight loss.