Effects of CPAP on Diet, Physical Activity, and Cardiovascular Risk
Condition: Sleep Apnea Syndromes
MeSH terms: Sleep Apnea Syndromes
Study type: Interventional

Summary: 
      Obstructive sleep apnea (OSA) is characterized by recurrent episodes of partial or complete
      loss of airflow during sleep, due to narrowing or closure of the upper airway. The resulting
      hypoxia has many cardiometabolic consequences, and leads to a disruption of sleep quality
      including reductions in the expression of rapid eye movement (REM) sleep and slow wave sleep
      (SWS). Patients also frequently experience excessive daytime sleepiness (EDS), which, when
      present with OSA, defines the clinical entity OSA syndrome (OSAS). Obesity is the leading
      risk factor for the development of OSA. Interestingly, it has been suggested that the
      disorder itself may contribute to further weight gain, presenting a vicious cycle wherein OSA
      and obesity perpetuate each other. OSAS may promote weight gain by placing patients in a
      state of positive energy balance characterized by low levels of physical activity and
      disrupted patterns of appetite-regulating hormones. Continuous positive airway pressure
      (CPAP), the gold-standard treatment of OSAS, may improve energy balance in these patients,
      although this has not yet been adequately studied. The current proposal will investigate the
      effects of 2 months of CPAP on energy balance and cardiovascular risk in obese patients with
      OSA. Patients will be instructed to use CPAP at home each night throughout the 2-month
      treatment phases. At baseline and at the conclusion of the 2-month treatment phase, the
      investigators will measure levels of free-living physical activity, sleepiness, sleep
      quality, body composition, cardiovascular risk factors, appetite-regulating hormones, hunger,
      and ad libitum food intake. There will also be a control group with OSA individuals studied
      at baseline and again after 2 months with no CPAP use. It is hypothesized that CPAP compared
      to no treatment treatment will result in improvements in energy balance, including increased
      physical activity, reductions in abnormally high levels of circulating leptin levels, and
      reductions in hunger, food intake, and cardiovascular risk factors. These improvements are
      hypothesized to be associated with increases in the expression of REM sleep and SWS, and
      reduced EDS as a result of CPAP.
    

Detailed description: 
      This study investigates the effects of 2 mo of continuous positive airway pressure (CPAP) on
      physical activity, energy intake (EI), and cardiovascular risk factors in overweight/obese
      patients with obstructive sleep apnea (OSA).

      Patients will be instructed to use CPAP at home each night throughout the 2 mo treatment
      phase. Before and after the 2 mo treatment phase, patients will undergo a 1-d in-lab testing
      period at the Clinical Research Resource (CRR) at Columbia University Medical Center. Upon
      completion of the laboratory phase 1, patients will return home for a 2 mo treatment period,
      followed by the second tracking period including laboratory visit 2.

      Before and at the conclusion of the 2 mo treatment phase, patients will enter the laboratory
      at the Columbia University Medical Center for a 1-d period. Patients will arrive at ~0800 h
      and will remain in the laboratory for the following 24 h. Blood will be sampled in the
      fasting state in the morning, and will be assayed for select appetite-regulating hormones
      (leptin, ghrelin, adiponectin, glucagon-like peptide-1). We will also assess body
      composition. During the laboratory day, ad libitum EI will be measured for each treatment
      phase. Breakfast, lunch, snack, and dinner will be served at the standard times, but each
      meal item will be served in excess such that patients will be able to eat as much or as
      little of each food as they choose. Additional snack choices will also be freely available
      during the wake episode.

      There will also be a control group of individuals with OSA who do not use CPAP who are
      studied at baseline and again after a 2 month period in procedures similar to those
      undergoing treatment.
    

Intervention name(s): CPAP
Intervention type(s): Device
Intervention description(s): use of CPAP each night for 2 months
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Intervention model description: treatment group: individuals with OSA using CPAP control group: individuals with OSA not using CPAP
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Sleep Apnea, Obstructive; Energy Balance; Food Intake; Energy Expenditure; Sleep; Obesity