When considering bariatric surgery think about bones

November 2, 2012

Bariatric surgery, which significantly curtails the amount of food a person can eat, is the most effective treatment against obesity and is being recognized as a potentially valuable tool in the fight against diabetes related to obesity. It is being performed on increasing numbers of people worldwide, including teenagers.

Unfortunately, some types of bariatric surgery may also cause bone loss, a cause for concern, particularly when carried out on young people who have not yet reached their peak bone mass, say endocrinologists from Sydney's , who have just published a review of current literature in the journal Obesity Reviews, now online.

Authors, Dr Malgorzata Brzozowska and Associate Professor Jackie Center, say that skeletal examination and treatment should be considered part of , before and after procedures.

In the United States, 'Roux-en-Y' gastric bypass surgery, one of the most invasive of the procedures, is the most common. Much of the stomach is removed and part of the bypassed. Less radical is the 'gastric sleeve', which involves removing a large part of the stomach leaving a narrowed smaller stomach, restricting and at the same time speeding the passage of food to the gut. The least invasive, and only reversible measure, is the 'gastric band', which is an inflatable ring placed between the oesophagus and stomach, making it possible to eat only small amounts of food slowly.

"Even though we don't yet understand all the mechanisms, we can see that the more radical the procedure, the greater the bone loss long-term," said Dr Brzozowska, who undertook the review as part of her PhD.

Dr Brzozowska is the first person to do a widespread analysis of current research into the complex between fat, bone and nutritional restriction.

"In many situations significant weight loss is associated with bone loss, with or without surgery. The more invasive types of surgery appear to heighten bone turnover and the associated . This is thought to be caused not only by rapid weight loss and absorption of fewer vital nutrients like vitamin D and calcium, but possibly also by changes in hormones released by fat and the gut, and their impact on the central nervous system," she said.

In particular, the review points out, we should be aware of surgery-induced changes in hormones that can affect the central regulation of appetite and bone strength. These include the fat-derived hormones leptin and adiponectin; gut-derived hormones such as peptide YY (PYY), glucagon-like peptide 1 (GLP-1) and ghrelin; and the hypothalamic regulator of energy balance, neuropeptide Y (NPY). However, although there is quite a lot of animal data concerning these hormones and their effects, human data are scanty.

Associate Professor Jackie Center believes that the findings are very important despite the widely held assumption that obese people are protected against bone fragility and fracture.

"It has always been assumed that the heavier someone is, the denser their bones will be, because bones become strong when they carry a load. While that is true up to a certain point, the bones may not continue to become stronger in the very obese, who can also have low bone density and fracture.

"Increasing evidence suggests that in very obese people, the relationship between bone density and weight fails and that the excess fat is detrimental to bone.

"While there are many studies looking at and improvement in insulin sensitivity after bariatric surgery, very few look at what happens in bone.

"We are certainly not arguing against bariatric . There is no doubt that it is an effective weapon against obesity and -related diabetes. We just ask that doctors and patients take bone health into account.

"Bone mineral densitometry scans can be done and adequate calcium and vitamin D intake advised. For those patients at particular risk, additional monitoring may be advised and protective drugs considered."

Explore further: Bariatric surgery does not increase risk of broken bones

Related Stories

Bariatric surgery does not increase risk of broken bones

August 6, 2012
An international study, led by researchers at the Medical Research Council Lifecourse Epidemiology Unit (MRC LEU) at the University of Southampton, has found that obese patients who undergo bariatric surgery are not at an ...

Vitamin D deficiency common among adolescents evaluated for weight-loss surgery

June 25, 2012
Most adolescents preparing for weight-loss, or bariatric, surgery are deficient in vitamin D, a new study demonstrates. The results to be presented at The Endocrine Society's 94th Annual Meeting in Houston.

Weight-loss surgery provides benefit to high-risk, severely obese patients

May 3, 2012
Among surgeries for obesity, a newer, increasingly popular procedure called sleeve gastrectomy provides more weight loss to high-risk, severely obese patients than adjustable gastric banding, a new study suggests.

Recommended for you

Policy and early intervention can curb obesity rates

December 18, 2017
More information and emphasis on dietary lifestyle changes that prevent obesity, and its comorbidities, have not reduced the rise in obesity in U.S. adults and adolescents, according to a recent study in the New England Journal ...

Warning labels can help reduce soda consumption and obesity, new study suggests

December 15, 2017
Labels that warn people about the risks of drinking soda and other sugar-sweetened beverages can lower obesity and overweight prevalence, suggests a new Johns Hopkins Bloomberg School of Public Health study.

Parents modeling healthy behaviors leads to markedly better outcomes for children

December 13, 2017
When trying to help children lose weight, involving a parent in the treatment makes the entire family healthier, researchers at Washington University School of Medicine in St. Louis have shown.

'Obesity paradox' not found when measuring new cases of cardiovascular disease

December 7, 2017
Although obesity is a well-known risk factor for getting cardiovascular disease, a controversial body of research suggests that obesity may actually be associated with improved survival among people who have cardiovascular ...

Harmful effects of being overweight underestimated

December 1, 2017
The harmful effects of being overweight have been underestimated, according to a new study that analysed body mass index (BMI), health and mortality data in around 60,000 parents and their children, to establish how obesity ...

More than half of US children will have obesity as adults if current trends continue

November 29, 2017
If current trends in child obesity continue, more than 57% of today's children in the U.S. will have obesity at age 35, according to a new study from Harvard T.H. Chan School of Public Health.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

Pam Peeke MD
not rated yet Nov 08, 2012
A key component of any responsible bariatric surgery is making sure the potential patient can stick to a restricted food plan for several months before the actual operation. If a patient is successful in losing weight on a food plan, shouldn't that demonstrate to the individual that s/he is capable of sticking with a balanced diet? Shouldn't those resources, financial and therapeutic, be devoted to making the lifestyle changes necessary to successfully maintain weight loss? Many patients find, after 18 months, that they are capable of reverting to their previous ways of eating, the consequences of which run the gamut from dumping to emergency corrective surgery. One of my patients, when asked about bariatric surgery, said she would only consider having it if she could also have a lobotomy. Not only is any surgery dangerous but you have underscored the long term complications and risks which sometimes unreasonable hopes ignore.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.