Sleep apnea is more common among obese people, and bariatric surgery is an effective way of helping obese people lose weight; however, it does not result in a significant improvement in obstructive sleep apnea (OSA), researchers from Monash University, Australia, wrote in the Journal of the American Medical Association.
Team leaders, associate Professor John Dixon, and Professor Matthew Naughton, carried out a randomized trial which compared the impact of surgery and supervised medication on obstructive sleep apnea in severely obese patients.
They found that the benefits of bariatric surgery, as far as obstructive sleep apnea was concerned, were “negligible”.
The authors explained that obstructive sleep apnea affects nearly 5% of Australia’s adult population. The person stops breathing for a length of time in their sleep – this period of no breathing during sleep is called an “apnea”. Severely obese people are more likely to have OSA because of the floppiness and/or heaviness around their faces and neck – OSA is caused by an obstruction to the upper airway.
Not only is sleep apnea undesirable and with some health consequences, it can also lead to some dangerous and potentially fatal diseases. In May 2012, scientists from the University of Wisconsin School of Medicine and Public Health warned that patients who suffer from sleep apnea are more likely to die from cancer. Another study said that OSA, which can deprive the brain of much needed oxygen, can increase the risk of developing dementia.
Professor Dixon and Naughton recruited volunteers for their study from various sleep centers. The participants had been recently diagnosed with moderate to severe OSA. They were all very obese, with a BMI (body mass index) of between 35 and 55. The researchers followed up the participants every four to six weeks for a period of two years.
Those who had undergone laparoscopic adjustable gastric banding (LAGB) lost an average of 20% of total body weight after two years. The participants in the “conventional group”, the ones who received advice and help with diet, exercise and behavioral programs, lost nearly 3% of their total bodyweight over the same period.
Despite a significant difference in weight loss between bariatric surgery and non-surgical intervention, Dixon explained that after carefully monitoring the two groups using polysomnography, there were “no significant improvements in obstructive sleep apnea”.
Prof Dixon said:
“Both groups experienced a reduction in OSA severity, but the difference between the surgical group and the conventional group was surprisingly small, given the weight loss disparity, and the majority still needed their CPAP machines during sleep.
Our research confirmed that weight loss is associated with reduction in OSA, but it’s a complex relationship. The effects vary greatly between individuals. It seems that the largest improvement in OSA, is associated with mild to moderate, rather than extreme weight loss.”
The researchers said health care professionals should be cautious when advising their obese patients with OSA, because telling them their symptoms will improve if they lose weight may be a myth. It is important that OSA therapies not be discontinued until a proper assessment is made of the patient. Prior studies have found that other surgeries do not help resolve sleep apnea symptoms either. Australian researchers reported in the BMJ in 2008 that upper airway surgery does not benefit OSA patients. However, patients with goiter who undergo thyroid surgery may have improved symptoms.
The authors concluded:
“Among a group of obese patients with OSA, the use of bariatric surgery compared with conventional weight loss therapy did not result in a statistically greater reduction in AHI despite major differences in weight loss.”
Obstructive Sleep Apnea, or OSA is a sleep disorder. The patient stops breathing during sleep for at least ten seconds. OSA occurs because the throat muscles relax, causing the soft tissue in the back of the throat to collapse and close, thus blocking the airways.
The episodes of not breathing are called apneas, which means “without breath”. In the United Kingdom, Ireland, Australasia, the word is spelled apnoea.
In OSA, breathing stops because of a physical obstruction to airflow, despite the patient’s effort to breathe. The person will commonly wake up after an apnea, but does not usually know he/she had not been breathing, and goes back to sleep. The patient’s sleeping partner, parents, siblings, or other people who share the same bedroom/dormitory are usually the first ones to notice the problem.
In obstructive sleep apnea, tissue at the back of the throat blocks the airways and the person cannot breathe
The majority of people with OSA snore, but not all of them.
According to the National Institutes of Health (NIH), USA, about 20% of all American adults have some degree of OSA. UK health authorities say about 3.5% of British males and 1.5% of females have some kind of sleep apnea. OSA is more common among people aged 40 or more years; however, it can affect people of any age, even children.
Very obese people have a high risk of developing OSA because of the extra fat that presses against the throat muscles.
Written by Christian Nordqvist