Advisory Committee Chair
S Justin Thomas
Advisory Committee Members
Date of Award
Degree Name by School
Master of Arts (MA) College of Arts and Sciences
Obstructive sleep apnea (OSA) is a common form of sleep disordered breathing that leads to poor daytime functioning. It is strongly associated with hypertension (HTN) and apneic events in individuals with OSA can drive blood pressure (BP) surges at night. Treating OSA with continuous positive airway pressure (CPAP) has led to reductions in day- and nighttime BP and treatment of HTN has also been reported to have beneficial effects on OSA severity. Dietary sodium has long been implicated in HTN and dietary sodium restriction improves BP levels. Recently, dietary sodium restriction was found to reduce OSA severity in men with severe OSA. While CPAP is effective in treating OSA, adherence is low; therefore, additional therapies may be needed. The goal of the current study was to determine the effect of dietary sodium restriction on OSA severity in adults with nocturnal HTN. Secondary data analysis was performed on 59 participants with nocturnal HTN who were recruited from the Coronary Artery Risk Development in Young Adults (CARDIA) study. Participants were enrolled into a randomized crossover feeding trial, which consisted of a high (6.0 g) and low sodium (1.5 g) diet period separated by a four-week washout period. They completed pre- and post-diet assessments, including clinic BP, 24-hour ambulatory BP, home sleep test (HST) and 24-hour urine collection. Change iii in OSA severity (apnea/hypopnea index, AHI) was examined according to both the intent-to-treat (ITT) and per protocol (PP) principles. No significant diet effect was observed in the ITT analysis. A sensitivity analysis was performed to examine the influence of HST evaluation duration; however, results were consistent with the initial findings. There was also no significant diet effect observed in participants when stratified by sex or race. Effect of dietary sodium restriction on OSA severity could not be assessed in the reduced sample of only adherent participants according to the PP principle due to a significant carryover effect. The current study suggests that dietary sodium restriction may not be an effective OSA treatment in adults with nocturnal HTN. Limitations, implications, and future directions are discussed.
Gloston, Gabrielle, "Intent-to-Treat Versus Per Protocol Analysis of a Crossover Feeding Trial: Effect of Dietary Sodium on Obstructive Sleep Apnea" (2023). All ETDs from UAB. 396.