Weight Loss Surgeries Increase Risk Osteoporosis Among Women: True or False

by Marixie Ann Obsioma, MT, undergrad MD on June 8, 2022
Last updated on June 4, 2022

Weight loss surgery and osteoporosis, is there really an association?

Weight Loss Surgeries Increase Risk Osteoporosis Among Women -True or False

The frequency of osteoporosis in patients having malabsorptive surgeries such as gastric bypass, also known as roux en y gastric, may be higher than previously assumed, necessitating increased monitoring and more targeted therapy choices for those identified with the bone mineral shortage.

Bone mineral deposition diseases can be treated with a variety of pharmacologic treatments. Osteoporosis therapy options for bariatric patients are discussed in this article, and the justification for their use by healthcare experts who specialize in this population. Serum nutritional parameter levels and bone mineral density measurements are also investigated as surveillance techniques.


Osteoporosis increases fracture risk. Bone mineral density and microstructure vary pathophysiologically. Osteoporosis is more common in women than in men. This disease’s effect on fracture risk may affect life expectancy and quality of life. Individuals who have had malabsorptive procedures like gastric bypass have a higher incidence of osteoporosis, requiring more monitoring and precise treatment choices than expected.

There are many pharmaceutical alternatives for bone-depositing diseases. Therapeutic and preventative interventions are plentiful. This article addresses osteoporosis treatment and preventive strategies for bariatric patients. Serum nutritional parameters and bone mineral density are also monitored.

Obesity has become an epidemic in the United States, with one-third of adults being overweight or obese.

If present weight trends continue, 86.3 percent of Americans will be overweight or obese by 2030, and no one will be standard eight by 2048, according to a report published in Obesity (Silver Spring).

In many cases, those with obesity who cannot shed pounds through diet and exercise opt for surgical weight loss intervention. There was a dramatic increase in bariatric procedures in the United States between 1998 and 2004. RYGB operations are expected to top 110,000 by 2011.

As much as 60% to 70% of excess weight is removed in the first two years following RYGB.

Restrictive mechanisms and malabsorptive processes may be to blame for this. Consumption and absorption of fewer calories due to the small gastric pouch capacity; decreased appetite due to decreased appetite-stimulating hormones; negative consequences of overeating, such as pain and vomiting; increased physical activity, which becomes more possible after patients lose weight; and malabsorption of nutrients as the result of bypassed anatomy all contribute to weight loss.

Proximal pouches and distal remnants of the stomach are separated during this procedure. A thin gastrojejunal anastomosis connects the upper pouch to the proximal jejunum.  A tiny section of the proximal jejunum (about 15–20 cm in length) is bypassed when food is swallowed, reducing gastric capacity to roughly 15–30cc.

In most cases, patients shed anywhere from 35 to 70% of their excess weight. Large-scale weight loss may alleviate or treat many obesity-related health problems, but skipping the remaining stomach and duodenum may reduce the absorption of nutrients, including iron and calcium and vitamins D and B12.

Malabsorptive Surgical Weight Loss Alters Calcium Homeostasis

A wide range of complicated concerns impacts the physiology of bones. As a result of their lack of physical activity, low vitamin D levels (perhaps owing to sunshine exposure), and poor food intake, morbidly obese patients usually have lower mineral bone density. Due to a decreased calcium absorption in the bypassed anatomy and a decreased intake of dairy products and suggested supplements, bariatric surgery may exacerbate excessive bone demineralization.

To maintain serum calcium levels, vitamin D deficiency will cause an increase in PTH secretion, which will cause bone resorption. Additionally, weight loss after bariatric surgery can lead to an increased risk of osteoporosis because of less stress on the central nervous system. Proton pump inhibitors (PPI) are frequently used in the bariatric population to prevent stomach ulcers, and this may be an additional mechanism for reducing gastric ulceration. These drugs have been shown to cause hypochlorhydria, which interferes with the absorption of absorbable calcium from insoluble calcium sources, such as supplements.

These many factors exacerbate osteoporosis in the surgical weight loss community. Bone mineral density in the hip, trochanter and total body of patients who underwent laparoscopic gastric bypass surgeries (LGBP) was considerably lower than that of obese controls in patients who underwent LGBP. According to the study, patients had an increase in bone resorption and a loss in bone mass within three months of surgery.

Pharmacological Treatments

Osteoporosis treatment options now include the following:

There are several antiresorptive agents, such as the bisphosphonates alendronate (Fosamax, Merck, and Co., Inc. Whitehouse Station, New Jersey), risedronate (Actonel), ibendronate (Boniva, Genentech USA Inc., South Sam Francisco, California), and zoledronic acid, that inhibits osteoclast-mediated bone loss (Reclast, Novartis Pharmaceuticals Corp., East Hanover, New Jersey). Osteoporosis can be prevented and treated with all of these. There are three oral medications: alendronate, risedronate, and ibendronate; the intravenous drug zoledronic acid is the only one.

Osteoporosis can be prevented and treated using the selective estrogen receptor modulator raloxifene (Evista), which decreases bone resorption and turnover.

Third, estrogen, which helps sustain bone loss after menopause and is approved to prevent osteoporosis, is authorized. The injection or intranasal administration of calcitonin, on the other hand, is approved for the treatment of osteoporosis but not for its prevention.

Forteo, a human parathyroid hormone injection, is only authorized to treat severe osteoporosis, regulate bone metabolism, and increase bone turnover. It is administered daily to patients who receive daily injections of Forteo (Forteo, Lilly USA, LLC, Indianapolis, Indiana).

There is no evidence to support the efficacy of bisphosphonates in the prevention of fractures in the spine and non-vertebral regions of the body. The single injectable medication, zoledronic acid, may be prohibitively expensive for some individuals.

As with estrogen, Raloxifene has the same benefits as HRT but has fewer adverse effects, including lower cholesterol and breast cancer risk. It also raises the risk of deep venous (DVT) and pulmonary embolisms (PEs) and hot flashes. For those undergoing bariatric surgery, the chances of the drug’s adverse effects may exceed the advantages.

As a therapy for osteoporosis, calcitonin primarily reduces vertebral fracture risk and is found to be the least powerful of all treatments.

As a therapy for osteoporosis, calcitonin reduces primarily vertebral fracture risk and is found to be the least powerful of all treatments.

While teriparatide reduces the incidence of vertebral and nonvertebral fractures, the monthly cost of about $700.00 for many patients may be prohibitive. The converse is also true:

Cranney et al. published a study of osteoporosis treatments in 2002. They found that the oral bisphosphonates alendronate and risedronate were the most effective in reducing the incidence of vertebral and nonvertebral fractures in osteoporotic individuals. In the nonsurgical weight loss group, oral bisphosphonates are an excellent starting point for treating osteoporosis. There is still a debate about which of these medicines is best for people who have undergone malabsorptive surgical weight loss operations.

Alendronate. There are two ways to take alendronate: once a day at 10mg or once a week at 70mg 30 minutes before the first beverage or food. 30 minutes after the medication has been administered, the patient must remain upright. Patients may experience esophagitis, esophageal and gastric ulcers, nausea, dyspepsia, muscle discomfort, and heart arrhythmias.

GI discomfort is the most prevalent complication. Alendronate’s efficacy is reduced if calcium supplements or antacids are not taken at least two hours after taking alendronate.

Black and Cummings described a study on how alendronate affects women with pre-existing vertebral fractures’ chance of breaking their hip or hip fractures in the future. The study lasted 36 months and covered 2,027 postmenopausal women. The study found a 55% reduction in fracture risk among women on alendronate compared to placebo; however, there were no significant changes in gastrointestinal symptoms among those taking alendronate and those receiving placebo.

Half of the individuals were given 70mg of alendronate weekly, whereas the other half received an equal placebo.  Three percent of participants dropped out of the study because of gastrointestinal issues, compared to just 11 percent of those who reported them. The manufacturer of Fosamax, Merck, supported this study.

Risedronate. Risedronate is a bisphosphonate that is the third generation. An oral dose is administered 30 minutes before ingesting any liquid or food. 30 minutes after the medication has been issued, the patient must remain upright.

Consequences of taking this medication include esophagitis, esophageal and stomach ulcers, nausea and vomiting, hypertension (HTN), edema of the hands and feet, dyspepsia, heartburn, depression, and musculoskeletal pains.

Abdominal pain and discomfort are the most frequent side effects. Risedronate’s efficacy is reduced if calcium supplements or antacids are not taken at least two hours after taking risedronate.

Eight randomized studies were reviewed by Cranney et al. in a Cochrane systematic review. Risedronate reduced the risk of vertebral and non-vertebral fractures clinically and statistically meaningful. Nonvertebral fractures occurred at a lower rate in those on risedronate than in those taking placebo, with 11% of the risedronate group experiencing a fracture compared to 17% of the placebo group.

According to Harris et al., 2,458 people participated in a randomized, controlled trial. The therapy options were oral risedronate 2.5 mg, oral risedronate 5 mg, or placebo. All of the subjects got 1,000 mg of calcium and, if necessary, vitamin D daily. After a year, the 2.5mg risedronate arm was deemed ineffective.

The other two sets of students had completed three years of schooling. After three years of taking 5mg risedronate daily, researchers reported a 41% reduction in vertebral fractures and a 39% reduction in nonvertebral fractures compared to placebo.

Gastrointestinal (GI) problems accounted for most research terminations due to adverse events (gastritis, dyspepsia). An EGD (esophagogastroduodenoscopy) was performed on 4.2% of patients in the risedronate group, and 85.3% had abnormal findings against 3.7% and 83% in the control group.

It’s Alendronate against Risedronate. Antiresorptive medicines were compared in a 2006 meta-analysis of randomized, controlled trials by Liberman et al. (alendronate, risedronate, ibandronate, raloxifene, HRT). There was a 34% reduction in overall risk with alendronate and a 26% reduction in the risk of vertebral and nonvertebral fractures with risedronate. Authors who worked at Merck contributed to this study.

On alendronate or risedronate after six months, 1.4% of patients had a nonvertebral fracture, while 0.6% of patients had the same problem with calcitonin. This was an observational, retrospective cohort analysis of 7,081 participants. Alendronate had a fracture rate of 2.4 percent after 12 months, while risedronate had a fracture rate of 0.9 percent. In the study, Actonel’s manufacturer employed three of the authors.

Alendronate and risedronate were determined to be ineffective in a 2005 systematic evaluation by the National Institute for Clinical Excellence (NICE).

Alendronate’s GI side effects compared to risedronate’s. Esophagitis, esophageal and gastric ulcers, and abdominal pain are some of the oral bisphosphonates’ most prevalent side effects. When administering any drug that can potentially influence gastrointestinal structures in post-gastric bypass patients adversely, the practitioner should use extreme caution. The small stomach pouch can get infected, resulting in considerable morbidity.   As a result, it is critical to select the least-irritating agent possible.

Alendronate and risedronate were examined in a 2004 Japanese study15 for their ability to irritate the mucous membranes of rats’ stomachs. While the researchers identified widespread exfoliation of epithelial cells without damaging the basement membrane in the gut after exposure to alendronate, they found no such damage after exposure to risedronate. Alendronate exposure to the gastric mucosa at doses of 60mg/kg or higher resulted in a significant delay in gastric ulcer healing. In contrast, risedronate exposure at doses as high as 100mg/kg resulted in a similar effect.

Safety of the Upper Gastrointestinal Tract

10,068 patients received oral risedronate 5mg daily for 1 to 3 years in a pooled analysis of nine clinical trials (multicenter, double-blind, placebo-controlled) to assess the prevalence of upper GI side effects associated with risedronate treatment.

A placebo was given to the control group. On average, both the risedronate and control groups had more than 1,900 patients with active GI disease at the outset, and 11.9% of risedronate participants took H2 blockers or PPIs, compared to 11.8% of control group participants. In the risedronate group, 0.7 percent of patients had upper gastrointestinal bleeding, while 0.9 percent had upper gastrointestinal bleeding in the control group.

Only 1.8 percent of the patients in both groups had esophagitis (1.8%), esophageal ulcer (0.5%), duodenal ulcer (0.3%), and Peptic ulcer (0.2%). Gastric ulcer bleeding was less common in one group than in the other (0.1 percent vs. 0.2 percent), and there were no perforations in either group.

Nonsteroidal anti-inflammatory medications (NSAIDs) and acetylsalicylic acid (aspirin) users were both somewhat more likely to experience upper gastrointestinal side effects (NSAIDs). According to the study’s findings, Risedronate was found to have no higher risk of serious upper gastrointestinal side effects when compared to a matching placebo group.

Researchers from Lanza et al. studied 515 postmenopausal women for two weeks, giving them either risedronate (5mg) or alendronate (10mg) as a daily oral dose. In the risedronate group, 4.1% of patients developed stomach ulcers, while 13.2% of patients in the alendronate group did. Risedronate individuals did not develop esophageal ulcers; however, 1.3 percent of alendronate participants developed ulcers. According to the findings, alendronate has a higher risk of stomach and esophageal ulcers while risedronate has a lower one.

Osteoporosis in male patients who have undergone gastric bypass surgery

Although osteoporosis is typically seen as a disease in women, 30% of hip fractures occur in men, and one in eight men over the age of 50 will suffer an osteoporotic fracture.

Ten years later than women, men are more likely to have hip, vertebral, or wrist fractures because of their greater peak bone mass.  According to research, osteoporosis in men is strongly linked to a man’s age, physical inactivity, and weight loss.

New osteoporosis screening guidelines for males recommend that they be screened for risk factors before the age of 65, when around 6% of men have osteoporosis, verified by a DEXA scan. DEXA scans are recommended for men with a family history of osteoporosis.

In men who have had gastric bypass surgery, few studies have looked at osteoporosis risk. Six women who had undergone bypass reversal surgery and five premenopausal women were enrolled in a small Canadian study. There were 13 postmenopausal women and seven postmenopausal women on HRT.

Before the trial, all participants had had weight loss surgery. DEXA scans evaluated bone mineral density in the lumbar spine (L2-L4) and the femoral neck. Men and postmenopausal women who were not on HRT had lower lumbar spine bone mineral density than the other groups, with the men being the most severely affected. There is no known cause for this dramatic shift in men’s appearance.

Before weight loss surgery, male gastric bypass patients should be screened for osteoporosis by having their height measured and checking their calcium, vitamin D, and testosterone levels. The death rate for men following a hip fracture is twice as high for men as for women. As a result of the Canadian study,20 one cannot conclude that male gastric bypass patients are more likely to suffer from osteoporosis than female ones.

Bone Density Analysis

DEXA scans are currently recommended for postmenopausal women over the age of 65 and males over 70 with risk factors. A one-year window for testing bone mineral density after gastric bypass surgery seems fair, given that the procedure can lead to increased bone resorption and decreased bone mass in as little as three months.


Should you be concerned about your bone health if you are considering a weight loss surgery? As per studies, yes, there can be a correlation. However, after a thorough examination of many trials, there are treatment options to prevent such side effect. One may conclude that risedronate may be the safer medicine to recommend for treating osteoporosis in gastric bypass patients. Risedronate is offered as a daily 5mg dose, a once-weekly 35mg dose, a twice-monthly 70mg dose on two consecutive days, or a once-monthly 150mg dose.

For osteoporotic fracture risk reduction, all amounts were equally efficacious with identical adverse event profiles. Depending on the patient’s schedule and preferences, daily, weekly, or monthly doses can be offered, improving adherence. To reduce the likelihood of gastrointestinal side effects, patients should be educated about how risedronate should be administered.

There have been no large-scale investigations on the safety and efficacy of oral bisphosphonates in the surgical weight reduction population. Humans’ absorption sites for these medications are unknown, but it is thought that the majority of absorption occurs in the small intestine.

After a gastric bypass, anatomical and physiological changes may have reduced absorption, although no research has looked into this. These issues should be discussed with individuals who have undergone gastric bypass and considered before beginning oral osteoporosis medication. If it is fiscally possible, intravenous zoledronic acid should be examined to administer bisphosphonates.

Patients’ nutritional status should be assessed at the outset of their recovery and frequently after their procedure. Follow-up should include labs such as calcium and vitamin D levels. They were taking calcium and vitamin D supplements after weight loss surgery is highly recommended for everyone who has had it.

As long as the patient and physician are ready and able to begin treatment, bone density testing should be done every one to two years for both men and women, regardless of their age. Regular bone density testing may not be cost-effective if the patient is unable or unwilling to adhere to a risedronate (or other osteoporosis medication) program.

As for other surgeries like laparoscopic adjustable gastric banding, the effects on bones are still subject for more research.


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