For patients with obstructive sleep apnea, initiation of continuous positive airway pressure is associated with a reduction in basal metabolic rate, according to a Doctors Lounge report.

Ryo Tachikawa, MD, PhD, from Kyoto University in Japan, and colleagues examined the mechanisms by which OSA patients gain weight after CPAP initiation. A comprehensive evaluation of energy metabolism was conducted in 63 participants with newly diagnosed OSA (51 men), CPAP initiation, and three-month follow-up. Participants underwent polysomnography, body weight, body composition, BMR, hormones, dietary intake, eating behavior, and physical activity measurements.

The researchers found that after CPAP there was a significant decrease in BMR (P < 0.001), but no change in physical activity or total caloric intake. Baseline apnea-hypopnea index, change in urine norepinephrine, and CPAP adherence were identified as significant predictors for the change in BMR in multivariate regression. Compared with non-weight gainers, weight gainers had higher leptin levels, lower ghrelin levels, and higher eating behavior scores. Increased caloric intake was a particularly significant predictor of weight gain among parameters related to energy metabolism.

“Although a reduction in BMR after CPAP predisposes to a positive energy balance, dietary intake and eating behavior had greater impacts on weight change,” the authors write. “These findings highlight the importance of lifestyle modifications combined with CPAP.”

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