WEDNESDAY, Nov. 28 (HealthDay News) -- Obese men with a lot of deep belly fat are at greater risk for bone-thinning than other men, a new study finds.

Although bone loss, or osteoporosis, is widely believed to be a health issue affecting women, researchers found that "visceral fat," which is located deep under the muscles in the abdomen, is linked to bone loss and decreased bone strength in men.

"Most studies on osteoporosis have focused on women. Men were thought to be relatively protected against bone loss, especially obese men," Dr. Miriam Bredella, a radiologist at Massachusetts General Hospital and associate professor of radiology at Harvard Medical School in Boston, said in a news release from the Radiological Society of North America.

"It is important for men to be aware that excess belly fat is not only a risk factor for heart disease and diabetes, it is also a risk factor for bone loss," Bredella added.

In conducting the study, the researchers examined 35 men with an average age of 34 years and an average body-mass index (BMI, a measure of height and weight) of 36.5, which is considered obese. The men had a CT scan of their abdomen and thigh to measure their fat and muscle mass. They also underwent a high-resolution CT scan, known as finite element analysis (FEA), of their forearm to determine their bone strength and risk for fractures.

"FEA is a technique that is frequently used in mechanical engineering to determine the strength of materials for the design of bridges or airplanes, among other things," explained Bredella. "FEA can determine where a structure will bend or break and the amount of force necessary to make the material break. We can now use FEA to determine the strength or force necessary to make a bone break."

The study revealed that the men with more visceral and total fat in their abdomen had less bone strength than those with less abdominal fat. The researchers noted that the men's age and total BMI did not have an impact on their bone strength.

"We were not surprised by our results that abdominal and visceral fat are detrimental to bone strength in obese men," noted Bredella. "We were, however, surprised that obese men with a lot of visceral fat had significantly decreased bone strength compared to obese men with low visceral fat but similar BMI."

The study, which was scheduled for presentation Wednesday at the annual meeting of the Radiological Society of North America in Chicago, noted that greater muscle mass is associated with increased bone strength.

The researchers pointed out that genetics, diet and exercise all play a role in the amount of visceral fat stored in the body. This type of deep belly fat is also linked to an increased risk for heart disease.

More than 37 million American men aged 20 years and older are obese, according to the U.S. National Center for Health Statistics. Obesity is linked to a number of health problems, including heart disease, diabetes, asthma, joint diseases and sleep apnea.

The data and conclusions of research presented at medical meetings should be viewed as preliminary until published in a peer-reviewed journal.

Although the researchers found an association between higher levels of belly fat and decreased bone strength, they did not prove a cause-and-effect relationship.

More information

The U.S. National Library of Medicine has more about osteoporosis.