A program for healthy weight loss significantly improved mild obstructive sleep apnea, according to results of a study of overweight adults aged 18-65 years.
Obesity is a known risk factor for obstructive sleep apnea (OSA), but no randomized studies have addressed whether weight reduction improves the condition, noted Dr. Henri P.I. Tuomilehto of the University of Kuopio (Finland), and colleagues.
In the study, the researchers randomized 72 overweight adults with mild OSA to a program that included a very-low-calorie diet and supervised lifestyle modification, or to a program of routine lifestyle counseling. The intervention included instructions for a very-low-calorie diet and 14 visits with a nutritionist during a 1-year period (including face-to-face meetings and group sessions), as well as recommendations for increasing physical activity. No specific exercise program was included in the intervention.
Improvements in OSA were objectively measured using the apnea-hypopnea index (AHI), and subjectively measured using a quality of life scale and patient reports of symptom changes. All participants had a body mass index between 28 and 40 kg/m
At 1-year follow-up, the intervention group achieved significantly greater weight loss on average, compared with the controls (11 kg vs. 2 kg). The average total AHI in the intervention group was 6 events per hour, which was significantly less than the average of 9.6 events per hour in the control group (Am. J. Respir. Crit. Care Med. 2009;179:320-7).
“Changes in AHI during the 12-month follow-up were strongly associated with changes in weight and waist circumference,” the researchers wrote. A 5-kg weight loss from baseline body weight was associated with a 2.0-unit reduction in AHI, and a 5-cm reduction in waist circumference was associated with a 2.5-unit reduction in AHI.
In addition, the intervention was associated with improvements in other obesity-related cardiovascular disease risk factors.
During follow-up, two of four patients in the intervention group who were taking oral diabetes medications were able to discontinue the medications, while two of the controls started taking diabetes medications. In all, 5 of 18 intervention patients were able to discontinue their antihypertensive medications, compared with 2 of 15 patients in the control group. And 6 of 12 patients in the intervention group who were taking cholesterol medications were able to discontinue them, compared with 3 of 18 controls.
Patients in the intervention group also reported improvements in quality of life, with scores nearly twice as high as the controls at the 1-year follow-up point. Patients in the intervention group also reported greater improvement in symptoms of OSA, including snoring and daytime sleepiness, compared with controls.
Long-term lifestyle changes can improve OSA, the researchers said. “Significant improvements were also found in symptoms related to OSA, insulin resistance, lipids, and cardiorespiratory variables, such as arterial oxygen saturation, in patients belonging to the intervention group,” they wrote.
The researchers had no financial conflicts to disclose.