Lifestyle Modification Program to Treat Obstructive Sleep Apnea Patients
Condition: Obstructive Sleep Apnea
MeSH terms: Apnea; Sleep Apnea Syndromes; Sleep Apnea, Obstructive
Study type: Interventional

Summary: 
      Obstructive sleep apnea syndrome (OSAS) is a common form of sleep-disordered breathing (SDB)
      characterized by repetitive episodes of cessation of breathing during sleep due to upper
      airway collapse. It causes sleep fragmentation, disabling daytime sleepiness, impaired
      cognitive function and poor quality of life. In addition, OSAS is associated with non-fatal
      and fatal cardiovascular consequences including sudden death, in addition to an increased
      risk of road traffic accidents. Continuous positive airway pressure (CPAP) is considered as
      the first-line treatment for OSA. Oral appliance has been shown to reduce the severity of
      sleep disordered breathing and leads to symptomatic improvement especially in mild to
      moderate OSA. The compliance with CPAP is low particularly in mild or moderate OSA patients
      and it is not a curative treatment of OSA. It has to be used in every night on a regular
      basis. Weight reduction has always been advocated in patients with OSA who are overweight and
      may lead to improvement in the severity of OSA. The existing studies about weight loss are
      limited by small sample size, short duration (<6 months), focus on very low calorie diet
      program or surgically induced weight loss program only. However, none of them have applied
      lifestyle modification program (LMP) which emphasizes on long term lifestyle and behavior
      change. Therefore, the investigators plan to conduct a randomized controlled trial among
      Chinese OSA patients by comparing the efficacy of LMP against usual clinical lifestyle advice
      alone on the improvement of OSA symptoms.
    

Detailed description: 
      Obstructive sleep apnea syndrome (OSAS) is a common form of sleep-disordered breathing (SDB)
      characterized by repetitive episodes of cessation of breathing during sleep due to upper
      airway collapse. It causes sleep fragmentation, disabling daytime sleepiness, impaired
      cognitive function and poor quality of life. In addition, OSAS is associated with non-fatal
      and fatal cardiovascular consequences including sudden death, in addition to an increased
      risk of road traffic accidents.

      OSAS is equally common among the middle-aged male Caucasian and Hong Kong (HK) Chinese
      populations with prevalence rates of at least 4%. The prevalence and severity of OSAS tend to
      increase through adult life, peaking in the late fifties to mid sixties, after which it fails
      to increase or decrease. Another group of investigators reported high prevalence rates of SDB
      in a group aged 65-95 years of 70% for men and 56% for women, at least double those reported
      for middle-aged cohorts.

      Risk factors for OSA include obesity, increasing age, being male, abnormal craniofacial
      morphology, nasal obstruction, genetic factors. OSA is associated with several cardiovascular
      consequences and social consequences e.g. motor vehicle accidents, impaired cognitive
      performance, depression. Various epidemiologic studies have shown an association between OSA
      and hypertension. In cross-sectional study, OSA was associated with increased prevalence of
      self-reported heart failure and stroke. OSA has been shown to be independently associated
      with coronary artery disease after adjustment for traditionally considered risk factors.

      Continuous positive airway pressure (CPAP) is considered as the first-line treatment for OSA.
      Oral appliance has been shown to reduce the severity of sleep disordered breathing and leads
      to symptomatic improvement especially in mild to moderate OSA. The compliance with CPAP is
      low particularly in mild or moderate OSA patients and it is not a curative treatment of OSA.
      It has to be used in every night on a regular basis. Weight reduction has always been
      advocated in patients with OSA who are overweight and may lead to improvement in the severity
      of OSA. A population-based longitudinal study showed that a 10% weight loss predicted a 26%
      decrease in apnoea-hypopnoea index (AHI), a count of the number of upper airway obstructions
      per hour of sleep.

      The existing studies about weight loss are limited by small sample size, short duration (<6
      months), focus on very low calorie diet program or surgically induced weight loss program
      only. However, none of them have applied lifestyle modification program (LMP) which
      emphasizes on long term lifestyle and behavior change. Therefore, the investigators plan to
      conduct a randomized controlled trial among Chinese OSA patients by comparing the efficacy of
      LMP against usual clinical lifestyle advice alone on the improvement of OSA symptoms.

      Aim of the study:

      The investigators aim to test the hypothesis that LMP is superior to lifestyle advice alone
      in the management of Chinese patients with OSA. The primary outcome measure is the change of
      AHI. The secondary outcome measures are changes in quality of life, symptoms related to OSA,
      glucose, and insulin metabolism parameters.

      Hypothesis:

      The investigators hypothesize that more OSA patients in a low glycemic index dietary
      intervention program than patients receiving simple lifestyle advice alone will have
      reduction in AHI.
    

Intervention name(s): Lifestyle modification; Simple lifestyle advice
Intervention type(s): Behavioral; Behavioral
Intervention description(s): During the first 4 months, subjects will come for a counseling session weekly and then monthly for the following months. During each counseling session (15 to 20 minutes), the registered dietitian will review the seven-day food diaries and offer recommendations for controlling caloric intake. A varied balanced diet with an emphasis on fruit and vegetables, and low-fat and low calorific products in appropriate portions were encouraged. The registered dietitian will also review the daily activity log sheet to check the exercise adherence and progression set by exercise instructor. Subjects will be encouraged to do 30 minutes aerobic exercise two to three times a week.; Subjects in control group will receive simple lifestyle advice from a clinician at baseline and month 6. This will be a brief discussion about the general health risk associated with OSA and importance of balanced diet. Subjects are encouraged to perform regular 30-minute exercise 2 to 3 times per week. This is to resemble routine clinical practice.
Other intervention name(s): Intervention group; Control group
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Investigator)
Primary purpose: Treatment