Impaired nasal breathing may prevent the beneficial effect of weight loss in the treatment of OSA.

SUMMARY Background: Weight loss is considered an effective treatment for obstructive sleep apnoea (OSA) in overweight patients. Some patients, however, do not benefit from weight loss. It has been postulated that nasal obstruction may act as an independent risk factor for OSA. Objective: The aim of our study was to evaluate whether impaired nasal airflow might explain the missing effect of weight reduction on OSA. Methodology : Fifty-two overweight adult patients with mild OSA were recruited. After the 12-month lifestyle intervention, all patients who achieved ≥ 5% weight loss were divided into two groups based on whether they still had OSA or not. Change in nasal resistance measured by rhinomanometer and AHI were the main outcome variables. Results : A total of 26/52 patients achieved 5% weight reduction. Of those 26 patients, 16 were objectively cured from OSA and 10 patients did not benefit from weight loss. Nasal resistance reduced significantly more in patients who had been cured from OSA. Smoking had a negative impact on both nasal resistance and improvement of AHI. Conclusions : Impaired nasal breathing and smoking may prevent the beneficial effects of weight reduction in the treatment of OSA.