Weight loss surgery increases the risk of bone fracture, researchers warn. Though bariatric surgery is known to reduce risk of heart attack and diabetes, it has detrimental effects to bone health.

In a study published in the journal Medicine, researchers from the College of Medicine at National Taiwan University in Taipei demonstrated that bariatric surgery, mainly with malabsorptive procedures, was significantly linked to an increased risk of overall fractures.

"The commonly lost nutrients are vitamin D and calcium, which are related to the development of osteoporosis and maybe there are other mechanisms associated with the development of fracture," Dr. Kuo-Chin Huang of the College of Medicine, National Taiwan University said.

Obesity is a growing predicament worldwide. In fact, according to the World Health Organization, more than 1.4 billion adults are overweight and more than half a billion are obese in 2008. Obesity is linked to an imbalance in the calories taken in and the calories burned during activities.

In the last 10 years, bariatric surgery, an operation wherein doctors reduce the size of the stomach or bypass parts of the digestive tract, increased seven-fold despite past studies suggesting that this procedure increases the risk of bone loss.

Though this type of surgery is known to reduce the risk of potentially-fatal diseases like heart attack, stroke and diabetes, its long-term survival and potential effects on health are not clearly understood. Many studies point out that weight loss surgery has negative effects on bone health such as increased bone turnover markers and decreased bone mineral density (BMD). These factors accelerate bone loss and increase bone fragility in the long run.

To land to their findings, the researchers used the National Health Insurance Research Database of Taiwan. They identified around 2,064 patients who underwent weight loss surgery between 2001 and 2009. These patients were compared to 5,027 obese people who did not undergo bariatric surgery.

Patients who had weight loss surgery had increased risk of bone fracture and bone loss

Those who underwent bariatric surgery had a 21 percent increased risk of breaking a bone or bone fracture in the next five years. At the end of the 12-year period, a total of 183 bone fractures in those surgical patients were noted.

Those patients who specifically had the malabsorptive procedures like gastric bypass had significantly higher fracture risk because of reduced absorption of important nutrients and vitamins essential for bone health. A 47 percent increased risk of having a fracture during the 12 years of follow-up was recorded compared to those who did not undergo the surgery.

Do the benefits outweigh potential risks?

"Therefore, the benefits should outweigh the potential risks if people know how to prevent or decrease the fracture risk," Huang said.

In a study published in the journal Plos Medicine, researchers from the London School of Hygiene and Tropical Medicine found that bariatric surgery reduces the risk of diabetes and heart attack. The largest comprehensive investigation of bariatric surgery in the United Kingdom which involved nearly 8,000 patients shows the health benefits of weight loss surgery for obese people.

In the United Kingdom, around 1.4 million people could benefit from this procedure. The researchers project that if all of these people would resort to bariatric surgery; it can reduce around 5,000 heart attacks and 40,000 type 2 diabetes cases for over four years.

The findings show that among those who have been diagnosed with diabetes, their condition improved and around 60 percent were taken off their medications.

"The results are really encouraging. Obviously we would love to help people lose weight in other ways, through exercise and healthy diets, but that's difficult. Diets do not always work well for everyone," study author Dr. Ian Douglas said.

"We are not saying surgery is right for everyone, but it can be really effective," he added.

In another study published in the European Journal of Preventive Cardiology, researchers found that bariatric surgery cut the risk of heart disease in morbidly obese patients. In fact, heart function returns to normal after weight loss surgery but not after lifestyle intervention.

"Obesity is a global problem that is closely linked to the development of cardiovascular disease. Morbidly obese patients are at high risk of heart attack, heart failure and diabetes," study author Dr. Magnus N. Lyngbakken, a doctoral candidate at the University of Oslo in Norway, said.

They found that in patients with morbid obesity, weight loss surgery was linked to greater reduction in high-sensitivity cardiac troponin I, an index of heart or myocardial injury than intensive lifestyle modification.

"The reduction appeared to be mediated by reductions in body weight and serum triglycerides. This suggests that weight loss following bariatric surgery may reduce cardiometabolic stress and subsequent risk of heart failure," the authors concluded in the study.

What can be done to avert bone loss?

The researchers recommend that surgical patients take supplements of vitamin D and calcium. Another effective preventive remedy is to have sun exposure and perform exercise to reduce the risk of osteoporosis.

"Lastly, they should perform some balance training to prevent falls," Huang added.

Photo: Emilio Labrador | Flickr 

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